If it helps Lime = Limestone Burn it in a Kiln = Quicklime Slake Quicklime in a little water = Hydrated Lime Slake Quicklime in a lot of water = Lime Putty (Lime putty can be also made from slaked hydrated lime) Hydraulic Lime = is impure limestone, Limestone with Silica and Clay Hydrated - meaning created by adding water Hydraulic - moved or activated by adding water Therefore Hydrated lime - created by adding water to quicklime Hydraulic lime - activated by the addition of water
Doesnt Hydraulic mean it cures with water and silica/ clay, like what cement does by binding water into its molecular structures, while airated meas it dries by evaporaring water into air. But i am neither a chemist nor a builder
Yeah you’re exactly right. The curing process is the same as what I was referring to when I said activated by the addition of water. I didn’t want to take the chance of everyone knowing that what I meant by saying curing
I am a lime enthusiast, having come to it after purchasing a stone-built (granite) cottage in northern Scotland that needs extensive work including the removal of slap-dash cement, internal plasterboard and the implementation of insulated (perlite/hemp) render. I have bought - and read - the English Heritage/Ashgate book on mortars renders and plasters, and have watched probably hundreds of hours of lime videos on RUclips, but I still feel like an absolute beginner. Some of those videos were excellent, but this one is _EXCEPTIONAL_ . Folks, if you are relatively new to lime then this video is your *NUMBER ONE* starting place; put everything else you have heard to one side and listen to this. Michael has covered here not just all the major points about lime but also debunked much of the confusing mythology and covered nuances that nobody else does. Tell your friends - this video is a factual and experience-led masterpiece. I am frankly shocked that at the time of writing it only has 140 likes. I had pretty much grasped the basics of lime before I watched this, but hadn't properly grasped the points about comparative free lime and the many small elements and differentiation nuances between not just quicklime and NHL, but within the NHL range and across manufacturers as well. I'll say it again, this video tutorial is _pure gold_ . I got all excited when packed earth mortar was mentioned because that's what I have; someone built my cottage in the mid/late 19thC using quarried and found granite, stabilised with a clay/grass/hair mix in the middle of the wall plus a lime/sharp sand rough mortar on the outside. It's absolutely fascinating to rake out the old joints and find 140 year-old nails and horse hair, mortar and packing not touched by anyone since the person who put it there. I'm off now to watch all the others in this series, especially around hot lime. I've invested in a forced action (paddle) mixer to make hot lime mortar instead of using NHL 2 (St Astier), but I still need to learn more about what to use in which situation, and whether there is a difference between using fresh hotlime mortar that is still warm and mortar that is cold and a week or so old. I have heard someone saying never to use hot lime that is still hot as it may still be expanding and can push a wall apart. True? Seems a bit unlikely to me as I'd expect any expansion to go outwards. My walls are half a metre or more wide, often with voids where the rubble has moved over the years, so I'm not too worried....or should I be? And should I be using hot lime for everything now, or does NHL have its place? (I need to use NHL 3.5 on the outside - I think? - because our outdoor lime season up here at 57.5°N is really short, and the winters can be harsh.) Thankyou for posting this outstanding educational resource. 👏
Hi there. Thanks for the comment. I'll be doing a video on hemp/perlite/sand insulating plaster before the year's out (hopefully). As far as NHL is concerned, in my opinion, there will always be a place for it but I think people need to become less reliant on it. The problem is, like cement, it's reliable as it's effectively a pozzolanised lime. There's no thought needed where pozzolana is concerned. Trouble is, it's so heavily loaded with it. This means a typical NHL3.5 is highly cementitious. With hot lime you can tailor the inclusion of pozzolan to suit your environment. I've used quiclime mortar with anywhere between 2% and 100% pozzolan - depending on the situation and I'm just so out of the habit of using NHL. Using it on a granite built property wouldn't bother me but I'd rather use a hot lime with pozzolan as you get expansion which means you get more volume. It also sets more quickly in comparison to NHL. We are now so acutely aware of the progressive strength gains of NHL that they're just a lot less relevant where flexural strength and capillarity are concerned. I still use them but mainly for plastering. Here I employ high free lime content NHL2s with added lime hydrate for workability. Hot mixed mortar needs to cook for a while but once it's absorbed all its moisture then it's good to go. As far as expansion is concerned: this is a good thing as it means there's a minute amount of it which translates to the possibility that it might/may fill joints better. But it really doesn't make a difference if it's applied hot or cold. Some prefer using it when there's still a good bit of heat in it but there are quite a few old wives' tails out there. The key is that it mostly allows for greater workability than an NHL which means you can fill joints fuller.
Please... would you be so kind to guide me? I replastered my straw bale home exterior walls as it was built 20 years ago. I used mix of 8 cups sand, 4 cups S hydrated lime, 1 cup Portland cement and water. Usually the standard practice is to mix dry materials and then add water. The way I did it, I was putting cement and lime into water, mixing it well and then adding sand. Everything was done quickly but got mixed very well. I finished whole house a month ago. Painted with natural pigment. It looks very nice. What will happen/will it provide longevity considering that I was not adhering to proper plaster preparation procedure? Will it start cracking, falling off or deteriorating in other ways? In other words, as a woman... i improvised with that mix like in the kitchen and did what requires less labor. Now I am scared.
I got the badge - thanks! wow - I feel like you made this video just for me - and I understand your speaking style - and love of cheap, local, easy materials. I'm in Canada and have plastered my 1890s old row house. I've learned a lot and used NHLs but reworked them and added other free lime too - and just covered old stones in the basement - and kept waiting for the magic self healing to start. I think it did a little actually. I just plater over the bits that crack - and that seems fine. FYI - yu did mention how great lime is a pulling moisture from the air! what used to be a damp cold basement is now dry and bright.
U provide continuous information and interesting facts continuously through this right to the very end. Other ppl after about 5 min are just filling the space with talk and no details. Most Excellent.
Thank you so much for taking the time to film and post this video, invaluable information. I think I'll need to watch it a few times again to absorb everything, but this really is worth its weight in gold knowledge-wise. I'm a builder and I'm going on my first lime course down to Ty Mawr next month, very much looking forward to it.
Good lad. I'm sure you'll enjoy it. There's actually a lot of work out there for builders who can work with lime. So many stick with cement. Sometimes I watch my videos and they just sound like a stream of consciousness so it says something about you if you can sift though them and clean what you need.
As promised... You know when you just know when you've stumbled upon a decent, concise, knowledgeable video, well it turns out that the vast majority of what I'd digested from this video was reiterated to me on the course last week at Ty Mawr. I'll definitely continue watching what you upload on here in future, it's proved very useful so far, so thank you again. I would definitely recommend the courses at Ty Mawr to anyone looking to further their understanding into the world of lime, I learnt a lot. Matt, Dale, Luke and Nigel were all very knowledgeable in their field. It was quick pace, but I feel a lot more confident armed with the knowledge coming from there, there's a lot to learn, but alongside this video, it made everything all that bit more familiar, which was great.
whenever i can, i reuse old lime mortar, broken up, when i rebuild flint walls or house walls, just put a couple of shovelfulls in a mix, usually 15 shovels sharp sand and 6 shovels of 3.5 lime, ( 10/4 mix) , ive tried hydrated and nhl 2, but have had failures in colder weather. some of the old mortars ive come across have been really hard, some have been blue in colour with black flecks in it, whilst others have been very light and sandy in colour, i am a flintknapper and have been doing it for 30 years now
Another insightful video. Along with Nigel, you have taught me a lot about limes. I was taught that nhls were the daddy, quicklimes are crap and putty is for ashlar. Now, after 13 years, I've changed my ways, and I'm glad I have.
I'm not a plasterer but I am involved with the trades. This was a most informative video. I was always led to believe that if cracks appear in lime mortar and that it would expand due to moisture ingress and partialy fill the crack. To learn that crystals form instead was in it's self, an eye opener. I live in a late 1800's 2 up 2 down in Norfolk and my house has had work done to it before and after I purchased it. I am in the process of unsealing the brickwork from gyps, portland cement and external splatter and trying to keep it as was. I will have to watch this more than a few times for it to all sink in. A simple, straight foward video that explains what is what and why. 👍
Thanks for sharing your experience, currently doing up our old house and finding getting good knowledge hard to find. Really enjoy the attempts I have made but be nice to develop better understanding of the mixes to use
Thank you Sir for your videos. I have learnt a lot from them. Thanks to you and Nigel Copsey I only used NHL for around a couple of weeks. And because I am also into baking my own sourdough bread I decided to stop using the NHL. Just like making my bread I want to know what is in my pointing mortar. Therefore I make hotlime mix from then on. 🙂
Currently binge watching pointing videos, as having my sandstone house repointed, left the contractor to it, came home and nearly cried. Massive lack of communication on both sides ended in all the new "cement mortar" raised repointing work having to be raked out. Great information. Very knowledgeable, exudes enthusiasm about lime. I'm completely on board with LIME!!! Probably gonna have to find the time to go it myself.
Extremely helpful Mr. Michael. I'll never point with 3.5 again. Great tip with the perlite addition to hydraulic as I just spent a fortune on Secil EcoCork. I'll be rewatching this video many a time to come to freshen up. Lots and lots in there. Thanks so much Michael I can't wait for my badge to arrive.
Well, great video very informative. Here in Melbourne Australia I’ve worked on lots of heritage listed buildings and the main architectural firm that gives council And conducts heritage overlays always advise Plasterer and or renders sand to be a nine sharps sand two hydrated lime one GP cement ratio to The same gauge. I’ve been using this for my whole career of 20 years. From experience Hasn’t fed me yet. I was interested to hear you use a 113 mix with hydrated and NHL lime. True to say that the hydrated lime gives it more body and work ability, In my Research i’ve read that no more than 10% of hydrated lime to a mix of NHL. I guess what you’re wanting to avoid is the shrinkage if you have too much hydrated line. ?? Anyway, great video you have a wealth of knowledge and you are actual tradesperson with experience. Good to hear and see. Cheers from down under.
There's never a worry about shrinkage. The only thing I can think of is that a lime hydrate will soften the mortar a bit. And that's no crime considering NHLs set bullet hard.
Hello Australia I was surprised to hear you use cement to set off your Hydrated there. It must be a climate thing. We get large rates of failure or weakening when doing this due to segregation especially with low Ievel cement mix's and the stronger mix's don't breathe.I'm guessing you lucky Aussie's don't get issues with damp. Hydraulic lime instead of cement is always an option.
great explanation, I recently tried hot lime but with powdered quicklime, now it makes sense why it didn't expand as much as I thought, still lots to learn.
Powdered still expands a great deal though. I slaked some putty in a galvanised bin recently… I thought it would take 2 bags of calbux and lots of water. It wasn’t funny! 🌋 😮
@@Terrahawks_Zelda yes I meant in comparison to kibbled quicklime when making mortar which definitely does expand more, the powder can be quite reactive when making putty or hot limewash, do be careful, I wear protection, gloves, mask and goggles, maybe overkill but I don't fancy getting lime burns or any of it in my eyes.
The amount of history and mystery involved with the use of lime, the various types, the ratio questions, the weather-related application questions etc makes it easy to see why some masons fell in love with Portland. The fact that the application of Portland over lime is problematic has not stopped a great many masons from doing just that. It makes me wonder what percent of those jobs were based on the expense of lime to the customer or the inexperience of the mason in regard to older structures.
I'm sure that all the old plasterers were doing cartwheel when sand and cement and gypsum plaster came in. I think a lot of pointing got done in cement because of price.
Thanks for the badge of completion! I learned a great deal, and yet feel at but the starting “point”.( pun intended) Thank you for sharing. I appreciate your content. Blessings fellow tradesman, and artist.🌊🌲🇺🇸☝️
Very usefull educational video.👍🏻 A suggestion for another video would be ,"all about cracks". It seems to be a big topic, especially on how to avoid them. Thank you.🙏🏻
Looking to bulid build a rock house in hot desert in Texas. Want to use a lime mortar. Can you build in hot dry conditions, what might be some things that could be done to stop the mortar from cracking.Also how does lime hold up long term in hot and dry conditions? Thinking i will use NHL but it will be expensive as it has to be shipped, could i mix an NHL 5.0 with a hydrated lime to make it like a NHL 3 and cut down in costs. Totally new to lime and stone masonry but have found ypur videos interesting.
Thank you for doing this. You have gifted a fantastic insight into the world of lime. My favourite line is : "I'm what's known as a need for cognition person" (34:38), which is exactly how I describe myself. I have been involved in a local retrofitting advice project and will be citing this video as the 'go to first' source of information on lime. We are renovating a c.1600 slate stone property in Cornwall and for the internal (exposed) walls will be rendering with an insulating mix. I will be using Saint-Astier NHL 2.0 and perlite. I'd also like to use the 'dust' (0-4mm) aggregate (granite) from the Hingston Down quarry, which is just a few miles away. What would be your recommendation for a recipe for this application? My interpretation from your video is: 1 part NHL 2.0, 1 part lime hydrate, 2 parts perlite, 1 part sand - any comments?
You might be going a bit too heavy on the perlite. I often use two sand, 1 perlite with NHL. You need hair or fibres for render. If two perlite will work then go with that. If you can afford pumice then swap out a sand for it.
Very good but can u be more specific about uses of hydrated lime. Can it be hot mixed and used as a render and also as a finish plaster. Does it need a pozlan.
I didn’t know you could use hot mixes for plastering as well. I thought it was just used for pointing or lime washing. Very interesting because as you say I’m paying a fortune for the pre mixed bags.
And they won't have the vapour permeability of lime. Add in your perlite, hemp or pumice and you'll have a superior product which can be tradtionally lime washed.
Absolutely brilliant and informative video. I was under the misguided belief that you could make lime putty by "slaking" lime hydrate and leaving to "mature" for a few days. I tried it many moons ago and the results were crap. Now I understand why. On a slightly different note, what is the purpose/benefit of adding lime hydrate to Portland cement mortar? Is it principally to improve workability or are there other benefits? Thanks again for a very detailed and informative video.
Hi Danny, the problem with making putty with lime hydrate is that you can just pour bags and bags of the stuff in your mixer with the end result being a massively lime rich lime hydrate putty. Once you try and add that to sand then you get a hugely lime rich mortar which can crack to buggery. You can certainly use it for plastering and pointing in it's powedered form but you have to guage it with your sand and lime when dry. When added to cement it works as a plasticiser but most builders don't do that now as cheap liquid plasticiser is now available in containers. I'm a great fan of lime hydrate as it's a pure lime but tend not to work with it because you can never rely on it having sufficient life left in it. And if it's left around for too long then it becomes inert.
Hi Michael. Watched all the way through, got the badge. I want to repoint some very delicate portico 1840 brickwork for a victorian london semi, scaffolding is up (for a different reason). Is it possible to do in Lime given the temps we will be expecting through January ? If it is what would you recommend ?
I work all year round. Only stop when temps are freezing during the day. Have a working day of 10 til 4. Use any lime depending on the vernacular. But not lime putty or lime hydrate.
I live in a part of Tennessee that is humid and has cold winters (sub freezing for days at a time) and hot summers, 90f plus for weeks at a time. I have a home I’m building. My exterior walls are 8” cinderblock (cmu) Whats your recommendation for exterior rendering? Quicklime is harder for me to get, can get NHL’s a bit easier… Can’t trust the suggestions I’m getting here, most of them have said to either mix Portland with hydrated lime or make putty out of hydrated lime…
What are your thoughts on rendering a cave? We used NHL 3.5 made by Cales Pascual in Spain mixed with white marble sand 0 to 2mm grade. The ground contains marble and other sedimentary rocks and fine almost dust layers of sand but also has a high salt content, it is a good strong finish so far (2 years) but does have salts coming to the surface in places especially where the ground is more prone to moisture travelling through the land.
so helpful....Michael thank you for reminding me of some of the knowledge my dad and his old crew of traditional builders passed to me.. inspiring me to do more. Do you know much about lime setups for bucket dipping bricks rather than troweling- a practice that was common locally here with handmade bricks at turn of the century??
Can you talk about lime mortar used with Accrington brick . Any experience repointing ? often existing mortar blackened with coal dust or naturally white but excessive hard very thin joints which the brick doesn't absorb much moisture from the mix .
Thank you it is a great video. I had been struggling to gather all of the informations on the web together in a neat way until I watched you. I want to ask: I plan to do rendering outside walls of a newly built house on top of hollow bricks and partly concrete in mid-winter. We have mild winters here, usually goes to 0 or 1 degree celcius at worst times. I have few bags of NHL 3.5 and synthetic fibers. Could I use 1 part of NHL 3.5 and 2 parts of lime and 2.5 parts of sharp sand as you have described on the video for this job? You had been talking about plaster mostly and I am confused about rendering. Second, for adding lime to NHL, can I use slaked lime on the site or just putty instead of lime hydrate? Or if I want to just use trass or wood ash instead of NHL bags, how should I use it exactly? Thank you in advance.
@@michaeljamesdesign Thank you for your reply. Yes, I am confused since nearly everyone has different opinions about lime on the internet. For render coats, should I add extra lime to NHL3.5? Like 1nhl:2lime:2.5 sharp sand. If so, should it be slaked lime from quicklime or putty or lime hydrate. Thank you again.
@@michaeljamesdesign Yes I saw. In the video you were talking about adding extra lime to increase the lime percentage of NHL. I thought I could apply the same idea to rendering. That's why I asked about it. I think you were talking about top coat plastering only then.
@@Hanokei Oh OK. I wouldn't add lime hydrate to NHL for outside. Only inside. When you say extra lime you must be absolutely specific about lime. Never just say lime.
Thank you so much for such a detailed download. I have a bag of St Astair 3.5 lyme in an opened bag that has sat about 5 years in a sealed polypropylene 5 gal tub in a temperature controlled, dry basement. Do you think it advisable to still use it for repointing, and do you have any videos on the different types of sand?
Would you ever suggest building a wall in front of a lime wall to create a cavity and tie into existing solid lime wall and then use normal plaster on the new wall ? Would there be any issues with doing this? I have some walls that I would like to soundproof but they are lime and solid walls..its basically a new build (converted butchers prep room built in 1890s) the walls are all over the place. They don't have damp as such but I have the space to create a cavity in front of the solid walls. My question is if I was to do something like this would I then be able to use normal plaster on the new block work wall and is it something that is possible to do without any problems as such...sorry if my question does not make sense. I've purchased a old property and would really like advice. I've been in the trade as a plumber for 22 years so I'm keen to learn more and try do the best for the property I have purchased. Thank you
Great video, much appreciated. Always love a Paul Daniel’s reference. Something I was wondering listening to the video - if you needed to replace bricks would you still use the pointing mortars as described? Or is that a different specification.
Erm, yeah, I was showing my age a bit with that one. For replacement bricks and stone you'd usually stick with the same mortar. Unless you had something lying around from previous work which you might want rid of.
Very informative video thankyou. I do have a couple of questions I am unsure of though, if you could help that would be great: What is it about a quicklime slaked to a putty which makes it better than a dry hydrate/hydrated lime wetted to putty ?, Im curious about what happens as they have both been slaked. Also, same type of question but why is a mortar made with quicklime, damp sand and water slaked and used as is (either cold or hot) better than a mortar made with sand added to the already slaked lime (I.e adding lime hydrate or putty to sand) ?
Dry hydrate is less workable and doesn't offer the same finish. For your second question you will not get a putty mortar to cure in winter whereas hot mixed mortar can be used throughout the year. Putty mortars also have less available lime because there is no expansion.
A great overview on lime use. In old construcion books and specifications one can find guidance to use freshly burnt quick lime. Was that because the quicklime would absorb moisture from the air and lose its strength? Have not seen all your videos, but would like to see something on what was done to make flexible mortars and mastics, such as for packing around windows.
Much of it was transported by barge. So on wet days you might find that in the top layer some slaking had occured. Architects used to get pissed off because they'd specified a mix but the masons would alter it to suit weather conditions. Same for lime hydrate. So cement became more popular with the designers as it meant they could specify without the need for the common sense and experience of the mason.
Great video, very useful, thank you. With regard to quicklime kibble vs quicklime powder, would the type of quicklime in use alter the ratio of it in your mortar mix? (say a 1:4 vs a 1:3 ?)
Hi Mike, thanks for putting together this video. Really helpful for us DIY-ers. Sorry to pester, but what would you prescribe using to repoint a red brick, arched cellar of an 18th century farmhouse up on a hill in Bristol? The old mortar seems to be giving way & letting quite a lot of wet through. Thanks in advance :)
As an american in America, i have come across the exact problem with lime putties. Its seeming near impossible to acquire lime to d.i.y. slake. And alot of lime putties that have been slaked and aged here is - slaked hydrated lime- lol. Its infuriating.
I feel your pain bruv. Just run some to a putty the night before and you'll be fine. But make sure, if you do, that you don't add the putty by volume. The problem with making lime putty this way is that you end up with a huge volume submersed in water because hydrate reduces down to nothing when you add water. So people end up putting the equivalent of 3 buckets of lime with 3 buckets of sand. Just take a gauge, mix it with water, lay it down overnight and incorporate with sand the next day.
@@michaeljamesdesign I’m in the USA as well and only have hydrated S-lime available. Instead of using the hydrated lime immediately I’ve been soaking it with water as long as I can (days/weeks) before use. I’m interested in finding affordable pozollans to increase its hydraulic qualities which would be useful for Tadelakt in the shower area. So far I’ve tried samples with pumice though I notice that the left over putty mix (when covered with a layer of water) still keeps well and doesn’t harden - is that a sign of the hydraulic qualities not working? How do you test for hydraulic qualities or the right amount of pozzolan to add? Appreciate any feedback you have!
@@daphnecharles2848 The problem with running pure hydrate to a putty is that it massively reduces in volume. I found that you can just add and add and add hydrate to a mixer. It just goes nowhere. The result is an extremely lime rich product. For example, an entire bag can fill one bucket. So I tend to use it only in powdered form. You can use it wet but now by volume. Additionally, water has an oxygen content which results in the lime being weakened. The easiest pozzolan to get hold of is wood ash. Like trass, this will increase the number of pores and pore sizes but large additions can be detrimental during the freeze/thaw cycle.
You have answered a lot of my questions already. I am in the process of building a stone cottage (24 inch thick walls) in northern Canada. I want to in sulate 2 of my 4 walls. I am wondering if I can build wainscoting to about 5 feet with an air gap and rigid foam board. Then render to the ceiling with hemp/perlite/sand/ lime mix you mention in the video. Have you seen walls like this before? Thanks
Thank you for sharing your expertise. I lasted the distance, but I don’t think I’m an aficionado just yet, sadly… My cottage (built 1604) near Buxton has been patched with all kinds of stuff over the years. Now it’s my turn on patching duty I’d like to make good choices! My first task is some holes in the bedroom plaster where some shelves were knocked out. I found old hay mixed into the lime plaster, which was an exciting discovery! Planning to get a chisel and try to remove the concrete that my father(?) has used to secure the shelves. I’m thinking now to avoid NHL. Need to do more research into quicklime, since I think this is the way to go, though slightly daunting. How do you store it please, if you get a sack and can’t use it all at once?
I truly appreciate the light your videos shed on the mystery of lime. While we in the northeast US don't have the really old buildings you have in the UK, we certainly have a great many built prior to the advent of Portland cement. Might I say that a great many have been repaired or repointed with Portland mixes. If one does internet research in the US we tend to get a lot of opinions that disagree. One thing that I am curious about is hydrated lime. Your videos say hydrated lime will setup if it is not so old as to have already carbonated in the bag. I wonder then, shouldn't hydrated lime be immediately moved into a plastic bucket, wetted and sealed airtight? I also wonder if NHL contains hydrated lime or quicklime. If it is hydrated lime, then why doesn't it act the same as regular hydrated lime?
Lime hydrate shrinks in volume when water is added so you can put loads into a bucket making it too rich. And you can't seal a container to make it air tight. NHL is lime kilned with impurities. It's hydraulic. Lime hydrate is an air lime.
@@michaeljamesdesign So if one added pozzolans to hydrated lime (or for the sake of conversation, even a lime putty), it would basically become NHL. Would adding pozzolans to lime putty make something comparable to NHL 2.0? It appears that quick lime is rarer than hen's teeth here in the US so we are left with a choice between lime putty and NHL and even those are hard to find in many areas. I am inclined to consider NHL 2.0 for pointing my 1910 brick home in Pennsylvania. Does that seem reasonable?
@@michaelk4935 NHLs and non-hydraulic limes are two different animals. Hydraulic means it'll set under water. Putty with pozz won't set under water. Nor will lime hydrate with pozz. Pennsylvania is cold - by all accounts. So NHL2 would depend on the situation and climate.
17:08 The Conserv website states their hot mix lime mortar made using Buxton Quicklime has a compressive strength of: 0.75 N/mm² ± (at 91 days) (which if accurate makes it less than equivalent to an NHL 1 if their was such a thing.) Not sure who carried out this test though and how reliable it is.
You know, soon after I made the comment about there not being a compressive strength figure for hot mixed mortar I remembered that there are actually figures. What we don't know is how they differ because of all the sands and pretty much everyone adds some kind of pozzolan even if it's just a colloidal sand. And there did actually used to be and NHL1 and Singleton Birch tried to roll one out but there was little demand. Gerrard Lynch has made some in his home kiln as well. Thanks for the comment and the figures, much appreciated. Keep 'em coming.
@@michaeljamesdesign No worries. Btw I’ve just been doing a load of plastering onto laths using quicklime and hair scratch and float coats. I’m finding it’s very prone to shrinking and cracking compared to when plastering onto bare brick and been having to float out the cracks every day until it carbonates which has took many days into weeks. Would an NHL have set quicker and been less prone to cracking do you think?
@@Terrahawks_Zelda A couple of times isn't really enough. I'll spray brickwork 3 or 4 times but lath needs a lot more. Do it a few times the day before then drench it and soak it before you apply. But trowelling out cracks is all part of quicklime. It'll always shrink more than NHL as it's got more lime. Hence it can be more expensive.
Please... would you be so kind to guide me? I replastered my straw bale home exterior walls as it was built 20 years ago. I used mix of 8 cups sand, 4 cups S hydrated lime, 1 cup Portland cement and water. Usually the standard practice is to mix dry materials and then add water. The way I did it, I was putting cement and lime into water, mixing it well and then adding sand. Everything was done quickly but got mixed very well. I finished whole house a month ago. Painted with natural pigment. It looks very nice. What will happen/will it provide longevity considering that I was not adhering to proper plaster preparation procedure? Will it start cracking, falling off or deteriorating in other ways? In other words, as a woman... i improvised with that mix like in the kitchen and did what requires less labor. Now I am scared. I wish I would have researched and was seeking for such advice before I started replastering my straw bale home walls. My wholehearted thanks for your time. If anyone besides the author of this video has any input, I sincerely welcome your feedback.
Hi there. I can't really help you as I don't use cement. All I can tell you is that it's bullet hard and impervious to moisture. Which means it shouldn't really be used for straw bale housing. This is probably why it's only lasted 20 years. It should last up to 10 times longer.
@@michaeljamesdesign I was told that straw bale home walls must be replastered every 15 years. Cob homes do not require such maintenance, but straw bale homes do. My main question is not about ingredients but the steps/sequence of mixing them I did. Thank you for your reply.
There were visible wear and tear ... some micro cracks around windows and at the bottom of walls which had most exposure to sun and rain. Some walls looked good while others required to be resealed.
Nice talk, enjoyed listening to it in it's entirety! Do you have experience and/or opinions on gauged quicklime with NHL hot mixed mortars? Can't seem to find much information on it, other than text references that it's apparently practiced commonly in Scotland among conservation specialists. I have experimented with a bit of pointing on an old brick garden wall and found 1 quicklime : 1 NHL : 5 sand (mix of different sized sharp sand + yellow sand for color) to be a nice compromise in terms of early setting and workability. Will find out soon enough whether it will withstand the winter here in Belgium. Also looks lovely when finished of using a stick and subsequently brushed when it's going off.
1:5 is a very weak mix - don't know how long that'll last. Gauging NHL into quicklime is a bad practise. It actually slows down the set - so if I were going to do it then it would be during summer only. Tried it in winter when I was out of pozzolan and it wasn't a good result on a number levels. Best to just bang in some decent pozzolan and stop adulterating the mix with that NHL.
@@michaeljamesdesign Interesting, I haven't found sources that state gauging as being bad practice. Also it's not actually 1:5, more like 1:2.5 binder : sand ratio. Of course not the same in terms of free lime content compared to 1 quicklime : 3 sand, but still about 60% free lime in the end (used NHL 3.5). This ratio is actually similar to what's suggested by David Wiggins in one of his presentations, and I've even found a reference from Nigel Cospey himself referring to 1 quicklime : 1 NHL : 6 sand as being close to historic lime to aggregate proportions. From my experience over the past spring and summer it didn't have issues with slow setting, except in a very damp corner but that's kind of expected.
@@michaeljamesdesign Because I'm still curious whether you or anyone else has some practical thoughts on the subject. Again there's very little info out there, and it's mostly references to some practitioners with no practical examples or experimental evidence. Wasn't trying to be dismissive, just sharing my thoughts here. I should indeed try to get my hands on some decent pozzolan but it's hard to find anything here on the mainland Europe, even getting powdered quicklime is hard and kibble is simply impossible unless you're willing to get a literal truckload :)
Hi Michael. Going to start building a boundary wall(rubble pennant stone) using st astier 3.5 Would the mix below be suitable please in a pretty exposed location. Lime..3.5..........1 Hydrated...........0.5 Sand.................4 or could you please advise.
Nigel Copsey. Secil's NHL has been found to contain some gypsum. EU standards don't demand much as far as detailed specifications are concerned so even the addition of inert chalk will pass as lime. It's all smoke and mirrors with NHL. So it's not a question of 'higher' gypsum, it's a question of it's inclusion. Put simply, it should not be there.
When you mix NHL with lime hydrate do you add water to the hydrate beforehand so as to make a "putty", or do you mix it all at once? Thanks for your videos.
It's OK, there's no need to put the word putty in quotation marks. I understand what you mean. No, you just chuck it in. Remember, it's mainly for extra workability when plastering - not pointing. Unless extra workability is a requirement.
Hi, i am trying to replace some of my lime plaster walls from the 40s. I cannot find quicklime. All I can easily get is called hydrated lime at an agriculture store. Can this be made to a lime putty by mixing with water in paint buckets? I believe paint buckets are pretty air tight. Thanks.
I have found some quicklime I can get. I believe I should make it into a slurry with water and leave it to slake for three months. Then I will have lime putty? Also will paint type buckets with lids work? Thanks again.
@@standleyt Yes you can slake the quicklime to a putty if you like and leave it for 6 months to mature for top coat plastering. But it's not something I do. I'm not expert concerning bucket lids. So I can't be very much help with that question. I'm sure there are plenty of tubs with lids on ebay.
Thank you for this video - it comes at exactly the right time! (That is, as I am trying to understand the various lime products available here in Austria.) Just one question, if I may: Why does mixing lime hydrate with more water not produce "real" lime putty? Or did you just mean that it still needs to sit for several months to mature?
The chemical formula is different. Lime hydrate is calcium hydroxide but lime putty (which is fully slaked) is calcium oxide. Lime hydrate is not as good as lime putty. The finish ain't the same. It's also a different white. Very white. Which means mortars are very very light indeed. Looks different to other limes. FYI: Otterbein is made in Deutschland.
@@michaeljamesdesign Forgive me if wrong in saying the expansion and heat you create with kibbled lime is a benifit you like having rather than hydrated bag lime?
@@295walk I've just slaked half a bag of quicklime I've had lying around for a couple of years. It was second hand when I got it so it's probably about two and a half years old. And it's fine. You could never to that with lime hydrate.
This was my question, as well. Twice in the course of the video Mr. James mentioned the unsuitability of lime hydrate--but it wasn't until his reply to this comment that he actually explained the reason, or at least partially explained it. With all due respect, that's a flaw in the presentation! Especially considering that a lot of us live in areas where lime hydrate is the only lime to be had.
@@gungadin164 I'd say it's less suitable for me but I'm not the blueprint for everyone else. Hydrate was very popular hundreds of years ago and it's a useable product today. And as far as flaws are concerned: I could pick holes in this monologue all day long
@@michaeljamesdesign I read a paper that studies the properties of lime-mortars in relation to the type of slaking that was used. The paper concluded that air-slaked lime yields the mortar with the best qualities. That conclusion took me by surprise. I work with powdered quicklime exclusively and I find that slaking is not always a super straightforward nor consistent procedure. Sometimes I add a certain amount of water and it heats up immediately. When I add the same amount of water to lime from a bag that had been open for a few weeks, the reaction is much slower. It takes 5 minutes before the water warms. Another thing I noticed, I always make milk of lime which I add to my earth mortars, is that if my water boils during slaking, the lime will clumps together. Apparently slaking above 100°C creates crystals and reduces the plasticity and surface area of the lime particles. Industrial slakers are recommended to run between 80° and 90°C. The close the lime is slaked to boiling, the higher the quality of the slake. But over 100°C and there are diminishing returns. I prefer to make milk of lime and not exceed 100°C also because there won't be any toxic fumes, which is an important consideration for as I often have to mix indoors. Just some of my observations!
@@DeWarmePlakker I find the same with lime which is getting a bit older. But usually it's got to be a couple of years old before the slake time increases. I made some lime wash a while ago and it set sold after I was stirring for about 5 minutes. I think the amount of moisture in sand might have something to do with how much water we use. The brand of lime is important too. Calbux is immediate and instantly hot, but Otterbein and Lincolnshire chalk lime take longer.
@@michaeljamesdesign I use Supervical from Carmeuse here in Belgium. I'm quite lucky it's an agricultural product because I don't think I would've found any quicklime in Belgium at all!
@@michaeljamesdesign it was a fascinating and amusing piece. This lecture and Nige's presentation in the Holy Land (parts 1&2) are, I believe, the most informative audio-visual references currently available to mankind, in terms of Lime and its correct use - precious resources indeed! Merry Christmas to both you and Nige!
This is full of information to those who are knowledgeable already. I am not in the slightest suggesting Michael James does not have huge experience and knowledge but as with many books as far as I can see its so subjective. It is using the terminology of centuries past, we might as well be referring to bushels , quarts and grains etc. Its like listening to a shaman discussing mixing frogs, newts and snakes to make magic potions. What is needed to bring the use of "lime" mortars , putty or what have you into the modern world is some absolute information. Some chemistry, some mesh sizes, grams and Kilogrammes in a table. End of talking about natural hydraulic lime , lime putty etc. w/o the chemistry and production mix definitions. Its like trying to understand Hungarian... for many .... maybe its just me?
Much of what we have had to go on to help us understand the way lime was used historically has all been bushels, sacks, pints and gallons. Aged recipes refer to aluminum sulphate as alum and it's expected of those who work with limes and colour-washes to know about traditional terminology. It's to be understood that a pint of ale can be used as a mordant and that a high clay content sand can be used to help set a lime mortar. How much you use is up to you because lime is all about feeling your way. It's like learning braille or swimming. You can only science it to some degree because it's a very inexact trade. But it's like all traditional trades and crafts, they all stem from knowledge gained many years ago and you learn by taste, smell, feel and sight. What works for one person in a particular environment might be a big mistake in another. What does work though is research. There's a lot of doctoral research which has provided evidence enabling us to understand historic mixed. Particularly in places like Israel - see Nigel Copsey. It's all out there and isn't too difficult to find - if you're prepared to do your spade work. If you joined the Building Limes Forum or searched for academic articles written by Dr G. Lynch then you'd certainly be able to understand lime plastering from a mesh size perspective.
@@michaeljamesdesign Thank you for your reply, I'll look for those links you mention. One aspect of all topics with extensive arcane language and terminology is that for experts it is so difficult to "unlearn" and see something from the position of the totally ignorant novice. This is where a good sciency reference book would help. It may exist but I've not found it. This does actually apply to ordinary cement mortar mixing too.
@@ianwhisson8064 You'll never get a good sciency reference book for lime in the same way you won't get one for roofing. But you can buy Dr G Lynch's books on Gauged Brickwork. You can also can buy N. Copsey's book on hot mixed mortars on Amazon. That's written off the back of a Masters dissertation. You can assemble a small library and that'll give you a start in the trade. Same for plumbing and electrics but if you're really intersted then go and do a practical course. What you're trying to do is the equivalent of trying to master the English language fluently after having only learnt English grammar. Learning just doesn't work like that.
I’m in an ongoing process of slaking a load of lime putty with quicklime for top coat plaster. I know they say ideally it wants to mature for at least 4 months before use. I’m going to hold off using it as long as possible but if I have to use some of it fresh will it still be ok? How does the maturation improve it exactly? Is it purely workability or will the end product be affected?
@@Terrahawks_Zelda there aren't any lumps to mature in powder so you can probably use it after a few weeks. The longer you leave it the more the lime breaks down.
Also you never finished your recipe for a “really good plastering mortar” because you got distracted by talking about how expensive and perfect pumice was, would you share that with me please? With and without the pumice/hemp?
@@flextacular6098 I believe I was talking about thermal plaster with the addition of hemp and pumice and that I'd happily use pumice as an aggregate instead of sand but can't afford it.
So many questions. I own a company that specializes in historic masonry restoration in Virginia. Would you be up for communicating by email? I don’t think this format lends itself to the detailed questions I’m dying to ask.
I’m also full of an eternity of questions up here in Canada , living and working as a stonemason in an historic town full of 150plus year old stone buildings.
@@leemills1357 This is the kind of subject your supplier should be telling you. It's made with argillaceous rock so this will always influnece colour in the direction of grey. Respectfully, you really should be in dialogue with your retailer. What do they say?
I got the badge and would get th t-shirt f sure, the times my partner walks in while im cooking or sipping some green wine and she says "you watching this guy again..!?" Hellas.. Very useful content thank you, we are reviving an old house in SE Portugal, most of the stone work is schist with lime rendering and pointing, at least what survived the last round of renovations that include whole walls in cement render.. Question: all of the original render/pointing has been done with a medium brown lime, coarse/ish sand, no hair, but it's brown or latte color. across the boarder in Spain I have been able to source hydrated lime that is latte colored, but it's a CL70, is this dogshit? we are just using it for plastering to mix & make the Secil lime warmer really, but Secil is the only stuff we can get our hands on.. there is some Keracoll stuff too that is 3.5 but comes as a ready mix and it's 20£ bag.. "breathability miracle" they sell it as.. The local builders use only NHL5 mixed with cement to tell clients it has lime.. it's sad to watch..
The brown lime plaster may even be earth/lime. There's still some around. CL70 is fine but you'll have to be careful slaking it as it's usually got a slow burn to it so you can easily drown it. Never buy premixed NHL because that's the dog shit stuff. NHL5 mixed with cement is just really bad. They don't need any cement whatsoever. "This guy" 😂😇 Ha ha!!
I watched the entire video, thank you for the information. I live on the east coast of the US in New York and am a mason. In my area we have some brick homes built with lime mortar. Typically the brick are very soft and easily affected by freeze thaw cycles. We are also very limited on what is available for NHL, forget about lime putty or hot lime. I found a place about 4 hours drive away that is selling NHL 2, 3.5, 5, I have a customer that wants there brick home repaired using their original brick and lime mortar could you suggest what I should use? I realize you haven’t seen the house and the question might not be answerable. Thank you for what you do.
@@michaeljamesdesignThe summer gets up to 95 degrees Fahrenheit, wet mostly, winters go to 20 below zero Fahrenheit at max now, used to be colder and more snow.
Oh dear, my bad. Did I really say that. I should've said something like 'Once this lime putty has been allowed to mature for a while you'll have mature lime putty'.
Been doing this, historic masonry restoration, for going on ten years. And, it went from almost no info and research and/or availability for materials in the USA. And, it has exploded in the research department, still mostly overseas, of course, but availability has gotten a little better.... it's still a little hard convincing officials on anything other than portland cement here. It's bogus.
You guys must have access to quicklime out there though as it's used by farmers to condition soil. www.mlc.com/products/quicklime/ It's probably miles away from you but anyone who can get quicklime in 25kg bags or even buy it in bulk bags and containerise it has a viable business.
@michaeljamesdesign negative goodsir. They used pulverized garden lime. Aka. Crushed limestone. Non hydraulic and non-reactive. Quicklime is considered hazardous. And, was nearly impossible to order anything over around 1kg from an industrial supply storehouse. Until a new restoration importer opened up shop last year allowing us access to quantity weight of kibble (quicklime) and even 30 yr aged lime putty from Italy! Woohoo. Guess im back to buying kilos again, only never thought it would be of the masonry kind.... guess prison didn't teach me anything the last time.... lmao
@@IannoneBuilding There us one more possibility and that's to do what we used to do which is to build a small kiln in your yard and burn some limestone. Nigel Copsey has had some success with home kilning.
@michaeljamesdesign ive actually attempted to fire limestone four times. On the last time, I reached the nearly 2800 degree mark for an hour and was so excited.... but, I noticed when I finally unloaded my lime a strange sulfur smell and knew something was wrong... but, i tested it anyways... taking a small amount and adding a drop of water... no reaction. I thought what the hell now!?! Then, I had a random thought of that sulfur smell... and, I quickly googled the formula for gypsum.... and, wouldn't you know, the fine 100% all natural high purity calcium chalk I used, was not actually chalk, but gypsum! I was devastated because firing large quantities of the fine powdered garden lime proved troublesome as to obtain the temp supplemental air is required (for a small campfire sized pit), and with powder, poof, gone like a fart in the wind. Second attempt, I welded a contraption that solved the blowing away issue, but instead ended up with so much ash, charcoal, and foreign matter in the end product it was useless.... and, the metal surround reduced the amount of heat exposure to the lime. Attempt three, adjusted my contraption, solved the debris problem, but couldn't get high enough temp for long enough due to wet wood. And then I switched to chalk because It was much easier to handle, lacked the problem of blowing away and even if debris got in, the chalk pieces were easy enough to remove. Just a little post fire sorting party. Lol. 🥳. And, I the stage was set, had dry wood, charcoal for the bottom, and an open enclosure. The flame was white, the chalk was glowing, which made me smile as you know when you've got the good stuff when your limestone glows luminescent usually. So, i was excited as a pig in shit, even recorded the whole process post-glow. So, you get 20 mins of me explaining and with a child like Gettiness. And, then, no sizzle... cue insane cussing rant of epic proportions at 5am, in suburbia, and....that video was erased from existence out of utter shame and devastation. Lmao. So, it's a work in progress, plan on trying again when I can get my hands on enough free limestone or "real" chalk!
Very interesting. I did watch the entire video, however, I did get confused with all the different lime terminology. I would appreciate, shorter videos then re- watch this one.
Very vague. Quick lime is Calcium Oxide. Hydrated lime Ca(OH)2 is lime putty. NHL has impurities which cause the lime to harden much more rapidly than pure lime and comes in different grades. You can turn hydraulic into non hydraulic by adding a pozzolan powder.
If it helps
Lime = Limestone
Burn it in a Kiln = Quicklime
Slake Quicklime in a little water = Hydrated Lime
Slake Quicklime in a lot of water =
Lime Putty (Lime putty can be also made from slaked hydrated lime)
Hydraulic Lime = is impure limestone, Limestone with Silica and Clay
Hydrated - meaning created by adding water
Hydraulic - moved or activated by adding water
Therefore Hydrated lime - created by adding water to quicklime
Hydraulic lime - activated by the addition of water
Doesnt Hydraulic mean it cures with water and silica/ clay, like what cement does by binding water into its molecular structures, while airated meas it dries by evaporaring water into air. But i am neither a chemist nor a builder
Yeah you’re exactly right. The curing process is the same as what I was referring to when I said activated by the addition of water. I didn’t want to take the chance of everyone knowing that what I meant by saying curing
@@krisg6365
Hammer
What i have since everyone uses different names.
CEB Earth Blocks Roman Concrete
Lime Earth Blocks Project
Quick Lime = Calcium Oxide CaO = Living Lime = Burnt Lime
Hydrated Lime = Slaked Lime = Fat Lime = Type S Lime = Hydrated Lime powder = Ca(OH)2 = Calcium Hydroxide = ?Dolomitic Hydrated Lime? = Best Egypt Hydrated Powder
Quick Lime / Calcium Oxide/ CaO + Water = Hydrated Lime/ Slaked Lime / Fat Lime / Type S Lime / Ca(OH)2 / Calcium Hydroxide etc
Quick lime expands and gets hot 🔥 can bind better. Keeps from cracking quick lime ( roman)
Idea: fat lime slacked lime added with a little quick lime
I have been looking for a video like this for over a year! Thank you from California!
I am a lime enthusiast, having come to it after purchasing a stone-built (granite) cottage in northern Scotland that needs extensive work including the removal of slap-dash cement, internal plasterboard and the implementation of insulated (perlite/hemp) render. I have bought - and read - the English Heritage/Ashgate book on mortars renders and plasters, and have watched probably hundreds of hours of lime videos on RUclips, but I still feel like an absolute beginner. Some of those videos were excellent, but this one is _EXCEPTIONAL_ .
Folks, if you are relatively new to lime then this video is your *NUMBER ONE* starting place; put everything else you have heard to one side and listen to this. Michael has covered here not just all the major points about lime but also debunked much of the confusing mythology and covered nuances that nobody else does. Tell your friends - this video is a factual and experience-led masterpiece. I am frankly shocked that at the time of writing it only has 140 likes.
I had pretty much grasped the basics of lime before I watched this, but hadn't properly grasped the points about comparative free lime and the many small elements and differentiation nuances between not just quicklime and NHL, but within the NHL range and across manufacturers as well. I'll say it again, this video tutorial is _pure gold_ . I got all excited when packed earth mortar was mentioned because that's what I have; someone built my cottage in the mid/late 19thC using quarried and found granite, stabilised with a clay/grass/hair mix in the middle of the wall plus a lime/sharp sand rough mortar on the outside. It's absolutely fascinating to rake out the old joints and find 140 year-old nails and horse hair, mortar and packing not touched by anyone since the person who put it there.
I'm off now to watch all the others in this series, especially around hot lime. I've invested in a forced action (paddle) mixer to make hot lime mortar instead of using NHL 2 (St Astier), but I still need to learn more about what to use in which situation, and whether there is a difference between using fresh hotlime mortar that is still warm and mortar that is cold and a week or so old. I have heard someone saying never to use hot lime that is still hot as it may still be expanding and can push a wall apart. True? Seems a bit unlikely to me as I'd expect any expansion to go outwards. My walls are half a metre or more wide, often with voids where the rubble has moved over the years, so I'm not too worried....or should I be?
And should I be using hot lime for everything now, or does NHL have its place? (I need to use NHL 3.5 on the outside - I think? - because our outdoor lime season up here at 57.5°N is really short, and the winters can be harsh.)
Thankyou for posting this outstanding educational resource. 👏
Hi there. Thanks for the comment. I'll be doing a video on hemp/perlite/sand insulating plaster before the year's out (hopefully). As far as NHL is concerned, in my opinion, there will always be a place for it but I think people need to become less reliant on it. The problem is, like cement, it's reliable as it's effectively a pozzolanised lime. There's no thought needed where pozzolana is concerned. Trouble is, it's so heavily loaded with it. This means a typical NHL3.5 is highly cementitious. With hot lime you can tailor the inclusion of pozzolan to suit your environment. I've used quiclime mortar with anywhere between 2% and 100% pozzolan - depending on the situation and I'm just so out of the habit of using NHL. Using it on a granite built property wouldn't bother me but I'd rather use a hot lime with pozzolan as you get expansion which means you get more volume. It also sets more quickly in comparison to NHL. We are now so acutely aware of the progressive strength gains of NHL that they're just a lot less relevant where flexural strength and capillarity are concerned. I still use them but mainly for plastering. Here I employ high free lime content NHL2s with added lime hydrate for workability. Hot mixed mortar needs to cook for a while but once it's absorbed all its moisture then it's good to go. As far as expansion is concerned: this is a good thing as it means there's a minute amount of it which translates to the possibility that it might/may fill joints better. But it really doesn't make a difference if it's applied hot or cold. Some prefer using it when there's still a good bit of heat in it but there are quite a few old wives' tails out there. The key is that it mostly allows for greater workability than an NHL which means you can fill joints fuller.
@@michaeljamesdesign Many thanks for the detailed reply - that's immensely helpful.
Kind regards.
Please... would you be so kind to guide me?
I replastered my straw bale home exterior walls as it was built 20 years ago. I used mix of 8 cups sand, 4 cups S hydrated lime, 1 cup Portland cement and water.
Usually the standard practice is to mix dry materials and then add water.
The way I did it, I was putting cement and lime into water, mixing it well and then adding sand. Everything was done quickly but got mixed very well. I finished whole house a month ago. Painted with natural pigment. It looks very nice.
What will happen/will it provide longevity considering that I was not adhering to proper plaster preparation procedure?
Will it start cracking, falling off or deteriorating in other ways?
In other words, as a woman... i improvised with that mix like in the kitchen and did what requires less labor. Now I am scared.
Best explanation on the subject yet. Thank you.
How very interesting.
Thanks for taking the time to explain everything so thoroughly.
I got the badge - thanks! wow - I feel like you made this video just for me - and I understand your speaking style - and love of cheap, local, easy materials. I'm in Canada and have plastered my 1890s old row house. I've learned a lot and used NHLs but reworked them and added other free lime too - and just covered old stones in the basement - and kept waiting for the magic self healing to start. I think it did a little actually. I just plater over the bits that crack - and that seems fine. FYI - yu did mention how great lime is a pulling moisture from the air! what used to be a damp cold basement is now dry and bright.
Hats off to you sir. Excellent information
Brilliant video, full of useful info. Thank you and thanks for the badge 😉
U provide continuous information and interesting facts continuously through this right to the very end. Other ppl after about 5 min are just filling the space with talk and no details.
Most Excellent.
Thank you so much for taking the time to film and post this video, invaluable information. I think I'll need to watch it a few times again to absorb everything, but this really is worth its weight in gold knowledge-wise. I'm a builder and I'm going on my first lime course down to Ty Mawr next month, very much looking forward to it.
Good lad. I'm sure you'll enjoy it. There's actually a lot of work out there for builders who can work with lime. So many stick with cement. Sometimes I watch my videos and they just sound like a stream of consciousness so it says something about you if you can sift though them and clean what you need.
Oh, and let me know how you get on. It'll be good for those who read the comments if they're thinking of doing the same course.
@@michaeljamesdesign I'll be sure to report back, thanks again for the reply 👍🏼
As promised...
You know when you just know when you've stumbled upon a decent, concise, knowledgeable video, well it turns out that the vast majority of what I'd digested from this video was reiterated to me on the course last week at Ty Mawr. I'll definitely continue watching what you upload on here in future, it's proved very useful so far, so thank you again.
I would definitely recommend the courses at Ty Mawr to anyone looking to further their understanding into the world of lime, I learnt a lot. Matt, Dale, Luke and Nigel were all very knowledgeable in their field. It was quick pace, but I feel a lot more confident armed with the knowledge coming from there, there's a lot to learn, but alongside this video, it made everything all that bit more familiar, which was great.
@@michaeljamesdesign I loved the stream of consciousness. you actually remind me of me - not a lad either.
whenever i can, i reuse old lime mortar, broken up, when i rebuild flint walls or house walls, just put a couple of shovelfulls in a mix, usually 15 shovels sharp sand and 6 shovels of 3.5 lime, ( 10/4 mix) , ive tried hydrated and nhl 2, but have had failures in colder weather. some of the old mortars ive come across have been really hard, some have been blue in colour with black flecks in it, whilst others have been very light and sandy in colour, i am a flintknapper and have been doing it for 30 years now
Another insightful video. Along with Nigel, you have taught me a lot about limes. I was taught that nhls were the daddy, quicklimes are crap and putty is for ashlar. Now, after 13 years, I've changed my ways, and I'm glad I have.
I was taught the same mate. But the scales slowly fall from one's eyes over time.
I'm not a plasterer but I am involved with the trades. This was a most informative video. I was always led to believe that if cracks appear in lime mortar and that it would expand due to moisture ingress and partialy fill the crack. To learn that crystals form instead was in it's self, an eye opener. I live in a late 1800's 2 up 2 down in Norfolk and my house has had work done to it before and after I purchased it. I am in the process of unsealing the brickwork from gyps, portland cement and external splatter and trying to keep it as was. I will have to watch this more than a few times for it to all sink in. A simple, straight foward video that explains what is what and why. 👍
"External splatter" 😂😂😂
Thanks for sharing your experience, currently doing up our old house and finding getting good knowledge hard to find. Really enjoy the attempts I have made but be nice to develop better understanding of the mixes to use
I found that fascinating. Thankyou.
Thank you Sir for your videos. I have learnt a lot from them. Thanks to you and Nigel Copsey I only used NHL for around a couple of weeks. And because I am also into baking my own sourdough bread I decided to stop using the NHL. Just like making my bread I want to know what is in my pointing mortar. Therefore I make hotlime mix from then on. 🙂
It’s the way to go
Thank you very much, best video about the topic I have found so far. I do plastering with lime putty (6 weeks old, works like a charm) and chalk 1:1.
Do you get any cracking?
Currently binge watching pointing videos, as having my sandstone house repointed, left the contractor to it, came home and nearly cried. Massive lack of communication on both sides ended in all the new "cement mortar" raised repointing work having to be raked out.
Great information. Very knowledgeable, exudes enthusiasm about lime.
I'm completely on board with LIME!!!
Probably gonna have to find the time to go it myself.
It's not rocket science and it sounds like you'll probably do a better job
Extremely helpful Mr. Michael. I'll never point with 3.5 again. Great tip with the perlite addition to hydraulic as I just spent a fortune on Secil EcoCork. I'll be rewatching this video many a time to come to freshen up. Lots and lots in there. Thanks so much Michael I can't wait for my badge to arrive.
Erm, yea, about that badge.......
Well, great video very informative.
Here in Melbourne Australia I’ve worked on lots of heritage listed buildings and the main architectural firm that gives council And conducts heritage overlays always advise Plasterer and or renders sand to be a nine sharps sand two hydrated lime one GP
cement ratio to The same gauge. I’ve been using this for my whole career of 20 years. From experience Hasn’t fed me yet.
I was interested to hear you use a 113 mix with hydrated and NHL lime. True to say that the hydrated lime gives it more body and work ability, In my Research i’ve read that no more than 10% of hydrated lime to a mix of NHL.
I guess what you’re wanting to avoid is the shrinkage if you have too much hydrated line. ??
Anyway, great video you have a wealth of knowledge and you are actual tradesperson with experience. Good to hear and see.
Cheers from down under.
There's never a worry about shrinkage. The only thing I can think of is that a lime hydrate will soften the mortar a bit. And that's no crime considering NHLs set bullet hard.
Hello Australia I was surprised to hear you use cement to set off your Hydrated there. It must be a climate thing. We get large rates of failure or weakening when doing this due to segregation especially with low Ievel cement mix's and the stronger mix's don't breathe.I'm guessing you lucky Aussie's don't get issues with damp. Hydraulic lime instead of cement is always an option.
great explanation, I recently tried hot lime but with powdered quicklime, now it makes sense why it didn't expand as much as I thought, still lots to learn.
Powdered still expands a great deal though. I slaked some putty in a galvanised bin recently… I thought it would take 2 bags of calbux and lots of water. It wasn’t funny! 🌋 😮
@@Terrahawks_Zelda yes I meant in comparison to kibbled quicklime when making mortar which definitely does expand more, the powder can be quite reactive when making putty or hot limewash, do be careful, I wear protection, gloves, mask and goggles, maybe overkill but I don't fancy getting lime burns or any of it in my eyes.
@@tyremanguitars I don’t think it is overkill, I’ve had some very dicey experiences when slaking quicklime.
Great breakdown would welcome a day in your company.
Need to watch that again to take it all in!
It's just one big waffle concerning lime really.
Very useful information
The amount of history and mystery involved with the use of lime, the various types, the ratio questions, the weather-related application questions etc makes it easy to see why some masons fell in love with Portland. The fact that the application of Portland over lime is problematic has not stopped a great many masons from doing just that. It makes me wonder what percent of those jobs were based on the expense of lime to the customer or the inexperience of the mason in regard to older structures.
I'm sure that all the old plasterers were doing cartwheel when sand and cement and gypsum plaster came in. I think a lot of pointing got done in cement because of price.
Thanks for the badge of completion! I learned a great deal, and yet feel at but the starting “point”.( pun intended) Thank you for sharing. I appreciate your content. Blessings fellow tradesman, and artist.🌊🌲🇺🇸☝️
Very usefull educational video.👍🏻
A suggestion for another video would be ,"all about cracks".
It seems to be a big topic, especially on how to avoid them.
Thank you.🙏🏻
Great video, thanks for sharing.
You're most welcome, thanks for commenting.
Great video content michael
Any advice on pointing and sealing around new timber sash windows 3.5 ? Love the vidios
Very good video, clear and easy.
Looking to bulid build a rock house in hot desert in Texas. Want to use a lime mortar. Can you build in hot dry conditions, what might be some things that could be done to stop the mortar from cracking.Also how does lime hold up long term in hot and dry conditions? Thinking i will use NHL but it will be expensive as it has to be shipped, could i mix an NHL 5.0 with a hydrated lime to make it like a NHL 3 and cut down in costs. Totally new to lime and stone masonry but have found ypur videos interesting.
Thank you for doing this. You have gifted a fantastic insight into the world of lime. My favourite line is : "I'm what's known as a
need for cognition person" (34:38), which is exactly how I describe myself. I have been involved in a local retrofitting advice project and will be citing this video as the 'go to first' source of information on lime. We are renovating a c.1600 slate stone property in Cornwall and for the internal (exposed) walls will be rendering with an insulating mix. I will be using Saint-Astier NHL 2.0 and perlite. I'd also like to use the 'dust' (0-4mm) aggregate (granite) from the Hingston Down quarry, which is just a few miles away. What would be your recommendation for a recipe for this application? My interpretation from your video is: 1 part NHL 2.0, 1 part lime hydrate, 2 parts perlite, 1 part sand - any comments?
You might be going a bit too heavy on the perlite. I often use two sand, 1 perlite with NHL. You need hair or fibres for render. If two perlite will work then go with that. If you can afford pumice then swap out a sand for it.
Very good but can u be more specific about uses of hydrated lime. Can it be hot mixed and used as a render and also as a finish plaster. Does it need a pozlan.
Hydrate has already been partly slaked so there will be no thermal reaction. And yes, use pozz.
What's the practical difference between lime putty from quicklime and slaked lime + water "lime putty"?
Hot mixed mortar goes off quicker and can be used all year round. Putty goes off much more slowly and can only used when it's above 10 degrees.
I didn’t know you could use hot mixes for plastering as well. I thought it was just used for pointing or lime washing. Very interesting because as you say I’m paying a fortune for the pre mixed bags.
And they won't have the vapour permeability of lime. Add in your perlite, hemp or pumice and you'll have a superior product which can be tradtionally lime washed.
@@michaeljamesdesignThe lime wash acts as a poultice to pull even more moisture out,correct?
@@ianwhitehead3086 Yes. And it'll do it to anything. Including dead bodies.
Absolutely brilliant and informative video. I was under the misguided belief that you could make lime putty by "slaking" lime hydrate and leaving to "mature" for a few days. I tried it many moons ago and the results were crap. Now I understand why. On a slightly different note, what is the purpose/benefit of adding lime hydrate to Portland cement mortar? Is it principally to improve workability or are there other benefits? Thanks again for a very detailed and informative video.
Hi Danny, the problem with making putty with lime hydrate is that you can just pour bags and bags of the stuff in your mixer with the end result being a massively lime rich lime hydrate putty. Once you try and add that to sand then you get a hugely lime rich mortar which can crack to buggery. You can certainly use it for plastering and pointing in it's powedered form but you have to guage it with your sand and lime when dry. When added to cement it works as a plasticiser but most builders don't do that now as cheap liquid plasticiser is now available in containers. I'm a great fan of lime hydrate as it's a pure lime but tend not to work with it because you can never rely on it having sufficient life left in it. And if it's left around for too long then it becomes inert.
@michaeljamesdesign Thank you very much for your reply, much appreciated 👍
Hi Michael. Watched all the way through, got the badge. I want to repoint some very delicate portico 1840 brickwork for a victorian london semi, scaffolding is up (for a different reason). Is it possible to do in Lime given the temps we will be expecting through January ? If it is what would you recommend ?
I work all year round. Only stop when temps are freezing during the day. Have a working day of 10 til 4. Use any lime depending on the vernacular. But not lime putty or lime hydrate.
I live in a part of Tennessee that is humid and has cold winters (sub freezing for days at a time) and hot summers, 90f plus for weeks at a time.
I have a home I’m building. My exterior walls are 8” cinderblock (cmu)
Whats your recommendation for exterior rendering? Quicklime is harder for me to get, can get NHL’s a bit easier…
Can’t trust the suggestions I’m getting here, most of them have said to either mix Portland with hydrated lime or make putty out of hydrated lime…
What are your thoughts on rendering a cave? We used NHL 3.5 made by Cales Pascual in Spain mixed with white marble sand 0 to 2mm grade. The ground contains marble and other sedimentary rocks and fine almost dust layers of sand but also has a high salt content, it is a good strong finish so far (2 years) but does have salts coming to the surface in places especially where the ground is more prone to moisture travelling through the land.
Sounds great!
so helpful....Michael thank you for reminding me of some of the knowledge my dad and his old crew of traditional builders passed to me.. inspiring me to do more. Do you know much about lime setups for bucket dipping bricks rather than troweling- a practice that was common locally here with handmade bricks at turn of the century??
Indeed. Dip 'em before you put 'em down.
Can you talk about lime mortar used with Accrington brick . Any experience repointing ? often existing mortar blackened with coal dust or naturally white but excessive hard very thin joints which the brick doesn't absorb much moisture from the mix .
I've got Accrington bricks did you figure this out yet?
Thanks mate great explanation 😊
Thank you it is a great video. I had been struggling to gather all of the informations on the web together in a neat way until I watched you.
I want to ask:
I plan to do rendering outside walls of a newly built house on top of hollow bricks and partly concrete in mid-winter. We have mild winters here, usually goes to 0 or 1 degree celcius at worst times. I have few bags of NHL 3.5 and synthetic fibers. Could I use 1 part of NHL 3.5 and 2 parts of lime and 2.5 parts of sharp sand as you have described on the video for this job? You had been talking about plaster mostly and I am confused about rendering. Second, for adding lime to NHL, can I use slaked lime on the site or just putty instead of lime hydrate? Or if I want to just use trass or wood ash instead of NHL bags, how should I use it exactly?
Thank you in advance.
You're still confused. For render coats and under top coat plaster you can use NHL3.5 with sand. but not at this time of year
@@michaeljamesdesign Thank you for your reply. Yes, I am confused since nearly everyone has different opinions about lime on the internet.
For render coats, should I add extra lime to NHL3.5? Like 1nhl:2lime:2.5 sharp sand. If so, should it be slaked lime from quicklime or putty or lime hydrate.
Thank you again.
@@Hanokei Did you see that I replied and suggested NHL3.5 with sand?
@@michaeljamesdesign Yes I saw. In the video you were talking about adding extra lime to increase the lime percentage of NHL. I thought I could apply the same idea to rendering. That's why I asked about it. I think you were talking about top coat plastering only then.
@@Hanokei Oh OK. I wouldn't add lime hydrate to NHL for outside. Only inside. When you say extra lime you must be absolutely specific about lime. Never just say lime.
Thank you so much for such a detailed download. I have a bag of St Astair 3.5 lyme in an opened bag that has sat about 5 years in a sealed polypropylene 5 gal tub in a temperature controlled, dry basement. Do you think it advisable to still use it for repointing, and do you have any videos on the different types of sand?
If it's still powdery then it's fine. No videos on sand yet.
Some "Brown" lime is just lime mortair with bit of iron oxide. So "brown" mens is contaminated during baking stage by rust (black and red oxides).
Absolut best explanation 😊 Thank you
Thanks Random Restore. Very kind of you to say.
Awesome video. Can you use agriculture lime? Which I am told is calcium carbonate.
Would like to know how to make venetian plaster?
Thanks again
Doing it properly is an art. Takes years. Mike Wye has a cheap and quick version but for proper traditional tadelact you really need to go to Italy.
please tell me, what would be best mix for stone house being built in the United States in climate zone 6 ?
There's a climate zone 6?
Thanks for the information!
Can you use bagged hydrated lime for brick laying/pointing?
You can. But not if it's old or has been exposed to air.
So much knowledge in one video. A master speaks.
Ha!
Would you ever suggest building a wall in front of a lime wall to create a cavity and tie into existing solid lime wall and then use normal plaster on the new wall ? Would there be any issues with doing this? I have some walls that I would like to soundproof but they are lime and solid walls..its basically a new build (converted butchers prep room built in 1890s) the walls are all over the place. They don't have damp as such but I have the space to create a cavity in front of the solid walls. My question is if I was to do something like this would I then be able to use normal plaster on the new block work wall and is it something that is possible to do without any problems as such...sorry if my question does not make sense. I've purchased a old property and would really like advice. I've been in the trade as a plumber for 22 years so I'm keen to learn more and try do the best for the property I have purchased. Thank you
Might be best to speak to someone who can give you a detailed pre-emptive condensation report.
Great video, much appreciated. Always love a Paul Daniel’s reference.
Something I was wondering listening to the video - if you needed to replace bricks would you still use the pointing mortars as described? Or is that a different specification.
Erm, yeah, I was showing my age a bit with that one. For replacement bricks and stone you'd usually stick with the same mortar. Unless you had something lying around from previous work which you might want rid of.
Hi Michael could you tell me what the pozzolan was you mentioned could not catch correct word thanks
Trass
Very informative video thankyou. I do have a couple of questions I am unsure of though, if you could help that would be great:
What is it about a quicklime slaked to a putty which makes it better than a dry hydrate/hydrated lime wetted to putty ?, Im curious about what happens as they have both been slaked.
Also, same type of question but why is a mortar made with quicklime, damp sand and water slaked and used as is (either cold or hot) better than a mortar made with sand added to the already slaked lime (I.e adding lime hydrate or putty to sand) ?
Dry hydrate is less workable and doesn't offer the same finish. For your second question you will not get a putty mortar to cure in winter whereas hot mixed mortar can be used throughout the year. Putty mortars also have less available lime because there is no expansion.
Thanks very much for responding, great to get an answer to this 👍
Hi! can i render concrete walls with lime and sand only mortar? will it hold? needs some special preparation? any advice would be helpful, thank you!
You can but there wouldn't really be much point.
A great overview on lime use. In old construcion books and specifications one can find guidance to use freshly burnt quick lime. Was that because the quicklime would absorb moisture from the air and lose its strength? Have not seen all your videos, but would like to see something on what was done to make flexible mortars and mastics, such as for packing around windows.
Much of it was transported by barge. So on wet days you might find that in the top layer some slaking had occured. Architects used to get pissed off because they'd specified a mix but the masons would alter it to suit weather conditions. Same for lime hydrate. So cement became more popular with the designers as it meant they could specify without the need for the common sense and experience of the mason.
Great video, very useful, thank you.
With regard to quicklime kibble vs quicklime powder, would the type of quicklime in use alter the ratio of it in your mortar mix? (say a 1:4 vs a 1:3 ?)
Yes. More lime with kibble or lump.
Hi Mike, thanks for putting together this video. Really helpful for us DIY-ers. Sorry to pester, but what would you prescribe using to repoint a red brick, arched cellar of an 18th century farmhouse up on a hill in Bristol? The old mortar seems to be giving way & letting quite a lot of wet through. Thanks in advance :)
As it's a cellar then I assume it's below ground so an NHL3.5 mixed 1:2.
@@michaeljamesdesign sorry for not mentioning originally, yes it is. Thanks for the response. Really appreciated
As an american in America, i have come across the exact problem with lime putties. Its seeming near impossible to acquire lime to d.i.y. slake. And alot of lime putties that have been slaked and aged here is - slaked hydrated lime- lol. Its infuriating.
I feel your pain bruv. Just run some to a putty the night before and you'll be fine. But make sure, if you do, that you don't add the putty by volume. The problem with making lime putty this way is that you end up with a huge volume submersed in water because hydrate reduces down to nothing when you add water. So people end up putting the equivalent of 3 buckets of lime with 3 buckets of sand. Just take a gauge, mix it with water, lay it down overnight and incorporate with sand the next day.
@@michaeljamesdesign I’m in the USA as well and only have hydrated S-lime available. Instead of using the hydrated lime immediately I’ve been soaking it with water as long as I can (days/weeks) before use. I’m interested in finding affordable pozollans to increase its hydraulic qualities which would be useful for Tadelakt in the shower area. So far I’ve tried samples with pumice though I notice that the left over putty mix (when covered with a layer of water) still keeps well and doesn’t harden - is that a sign of the hydraulic qualities not working? How do you test for hydraulic qualities or the right amount of pozzolan to add? Appreciate any feedback you have!
@@daphnecharles2848 The problem with running pure hydrate to a putty is that it massively reduces in volume. I found that you can just add and add and add hydrate to a mixer. It just goes nowhere. The result is an extremely lime rich product. For example, an entire bag can fill one bucket. So I tend to use it only in powdered form. You can use it wet but now by volume. Additionally, water has an oxygen content which results in the lime being weakened. The easiest pozzolan to get hold of is wood ash. Like trass, this will increase the number of pores and pore sizes but large additions can be detrimental during the freeze/thaw cycle.
You have answered a lot of my questions already. I am in the process of building a stone cottage (24 inch thick walls) in northern Canada. I want to in sulate 2 of my 4 walls. I am wondering if I can build wainscoting to about 5 feet with an air gap and rigid foam board. Then render to the ceiling with hemp/perlite/sand/ lime mix you mention in the video. Have you seen walls like this before? Thanks
Thank you for all your efforts, and No BS.
Very informative and much appreciated.
Michael.
Dublin.
Thank you for sharing your expertise. I lasted the distance, but I don’t think I’m an aficionado just yet, sadly… My cottage (built 1604) near Buxton has been patched with all kinds of stuff over the years. Now it’s my turn on patching duty I’d like to make good choices! My first task is some holes in the bedroom plaster where some shelves were knocked out. I found old hay mixed into the lime plaster, which was an exciting discovery! Planning to get a chisel and try to remove the concrete that my father(?) has used to secure the shelves. I’m thinking now to avoid NHL. Need to do more research into quicklime, since I think this is the way to go, though slightly daunting. How do you store it please, if you get a sack and can’t use it all at once?
You can get it in tubs from Womersleys or cornish lime.
I truly appreciate the light your videos shed on the mystery of lime. While we in the northeast US don't have the really old buildings you have in the UK, we certainly have a great many built prior to the advent of Portland cement. Might I say that a great many have been repaired or repointed with Portland mixes. If one does internet research in the US we tend to get a lot of opinions that disagree. One thing that I am curious about is hydrated lime. Your videos say hydrated lime will setup if it is not so old as to have already carbonated in the bag. I wonder then, shouldn't hydrated lime be immediately moved into a plastic bucket, wetted and sealed airtight? I also wonder if NHL contains hydrated lime or quicklime. If it is hydrated lime, then why doesn't it act the same as regular hydrated lime?
Lime hydrate shrinks in volume when water is added so you can put loads into a bucket making it too rich. And you can't seal a container to make it air tight. NHL is lime kilned with impurities. It's hydraulic. Lime hydrate is an air lime.
@@michaeljamesdesign So if one added pozzolans to hydrated lime (or for the sake of conversation, even a lime putty), it would basically become NHL. Would adding pozzolans to lime putty make something comparable to NHL 2.0? It appears that quick lime is rarer than hen's teeth here in the US so we are left with a choice between lime putty and NHL and even those are hard to find in many areas. I am inclined to consider NHL 2.0 for pointing my 1910 brick home in Pennsylvania. Does that seem reasonable?
@@michaelk4935 NHLs and non-hydraulic limes are two different animals. Hydraulic means it'll set under water. Putty with pozz won't set under water. Nor will lime hydrate with pozz. Pennsylvania is cold - by all accounts. So NHL2 would depend on the situation and climate.
17:08 The Conserv website states their hot mix lime mortar made using Buxton Quicklime has a compressive strength of: 0.75 N/mm² ± (at 91 days) (which if accurate makes it less than equivalent to an NHL 1 if their was such a thing.) Not sure who carried out this test though and how reliable it is.
You know, soon after I made the comment about there not being a compressive strength figure for hot mixed mortar I remembered that there are actually figures. What we don't know is how they differ because of all the sands and pretty much everyone adds some kind of pozzolan even if it's just a colloidal sand. And there did actually used to be and NHL1 and Singleton Birch tried to roll one out but there was little demand. Gerrard Lynch has made some in his home kiln as well. Thanks for the comment and the figures, much appreciated. Keep 'em coming.
@@michaeljamesdesign No worries. Btw I’ve just been doing a load of plastering onto laths using quicklime and hair scratch and float coats. I’m finding it’s very prone to shrinking and cracking compared to when plastering onto bare brick and been having to float out the cracks every day until it carbonates which has took many days into weeks. Would an NHL have set quicker and been less prone to cracking do you think?
@@Terrahawks_Zelda How long did you spend wetting the lath?
@@michaeljamesdesign I sprayed the lath 2-3 times periodically before starting.
@@Terrahawks_Zelda A couple of times isn't really enough. I'll spray brickwork 3 or 4 times but lath needs a lot more. Do it a few times the day before then drench it and soak it before you apply. But trowelling out cracks is all part of quicklime. It'll always shrink more than NHL as it's got more lime. Hence it can be more expensive.
I remember watching my father render a strawbale house he built 20+ years ago. He would batch up quicklime and make it into render
Sounds like a good man.
May I ask how long you have been involved with the lime trade/building trades and where you were trained pleased
17 years in the lime, 21 working with mortar. Self taught apart from a bit of help here and there. It's not something you can go to college to learn.
Please... would you be so kind to guide me?
I replastered my straw bale home exterior walls as it was built 20 years ago. I used mix of 8 cups sand, 4 cups S hydrated lime, 1 cup Portland cement and water.
Usually the standard practice is to mix dry materials and then add water.
The way I did it, I was putting cement and lime into water, mixing it well and then adding sand. Everything was done quickly but got mixed very well. I finished whole house a month ago. Painted with natural pigment. It looks very nice.
What will happen/will it provide longevity considering that I was not adhering to proper plaster preparation procedure?
Will it start cracking, falling off or deteriorating in other ways?
In other words, as a woman... i improvised with that mix like in the kitchen and did what requires less labor. Now I am scared. I wish I would have researched and was seeking for such advice before I started replastering my straw bale home walls.
My wholehearted thanks for your time. If anyone besides the author of this video has any input, I sincerely welcome your feedback.
Hi there. I can't really help you as I don't use cement. All I can tell you is that it's bullet hard and impervious to moisture. Which means it shouldn't really be used for straw bale housing. This is probably why it's only lasted 20 years. It should last up to 10 times longer.
@@michaeljamesdesign
I was told that straw bale home walls must be replastered every 15 years. Cob homes do not require such maintenance, but straw bale homes do.
My main question is not about ingredients but the steps/sequence of mixing them I did.
Thank you for your reply.
@@oldworldwildona550 Why would they need plastering every 15 years?
There were visible wear and tear ... some micro cracks around windows and at the bottom of walls which had most exposure to sun and rain. Some walls looked good while others required to be resealed.
@@oldworldwildona550 The cracks were likely caused by the fact that the cement made the render brittle. You need a flexible mortar. No cement.
I loved the whole video 🔅
Nice talk, enjoyed listening to it in it's entirety! Do you have experience and/or opinions on gauged quicklime with NHL hot mixed mortars? Can't seem to find much information on it, other than text references that it's apparently practiced commonly in Scotland among conservation specialists.
I have experimented with a bit of pointing on an old brick garden wall and found 1 quicklime : 1 NHL : 5 sand (mix of different sized sharp sand + yellow sand for color) to be a nice compromise in terms of early setting and workability. Will find out soon enough whether it will withstand the winter here in Belgium. Also looks lovely when finished of using a stick and subsequently brushed when it's going off.
1:5 is a very weak mix - don't know how long that'll last. Gauging NHL into quicklime is a bad practise. It actually slows down the set - so if I were going to do it then it would be during summer only. Tried it in winter when I was out of pozzolan and it wasn't a good result on a number levels. Best to just bang in some decent pozzolan and stop adulterating the mix with that NHL.
@@michaeljamesdesign Interesting, I haven't found sources that state gauging as being bad practice. Also it's not actually 1:5, more like 1:2.5 binder : sand ratio. Of course not the same in terms of free lime content compared to 1 quicklime : 3 sand, but still about 60% free lime in the end (used NHL 3.5). This ratio is actually similar to what's suggested by David Wiggins in one of his presentations, and I've even found a reference from Nigel Cospey himself referring to 1 quicklime : 1 NHL : 6 sand as being close to historic lime to aggregate proportions.
From my experience over the past spring and summer it didn't have issues with slow setting, except in a very damp corner but that's kind of expected.
@@victorchamberland2232 Why ask my advice then? Why ask the road you already know?
@@michaeljamesdesign Because I'm still curious whether you or anyone else has some practical thoughts on the subject. Again there's very little info out there, and it's mostly references to some practitioners with no practical examples or experimental evidence. Wasn't trying to be dismissive, just sharing my thoughts here.
I should indeed try to get my hands on some decent pozzolan but it's hard to find anything here on the mainland Europe, even getting powdered quicklime is hard and kibble is simply impossible unless you're willing to get a literal truckload :)
w@@victorchamberland2232 Wood ash.
Hi Michael.
Going to start building a boundary wall(rubble pennant stone) using st astier 3.5
Would the mix below be suitable please in a pretty exposed location.
Lime..3.5..........1
Hydrated...........0.5
Sand.................4
or could you please advise.
Too much sand
@@michaeljamesdesign thanks Michael would 3 sand work please
@@kruger-w You could go 1:1, 1:2 or 1:3. But it'd depend on the spec. 1:3 works for most people.
Thanks for the video, what is trase ?
Trass: crushed volcanic rock. Pozzolan.
@michaeljamesdesign thanks very much, im a plasterer looking ti get into doing lime work. Doing the second part of a coarse next month.
@@neilrollason Well done bruv, as an existing spread you should do really well. There's so much work out there for good lime plasterers.
Thanks for the support 🙏 any bullet points tips,much appreciated 👍im in Coventry, hopefully will get work in surrounding areas, villages etc.
@@neilrollason Make a scratcher out of old lath. Don't use one of those combs.
At around the 24 minute mark he suggests that one NHL has higher Gypsum. Which one? Who's the expert? Please 🙏. Thank you.
Nigel Copsey. Secil's NHL has been found to contain some gypsum. EU standards don't demand much as far as detailed specifications are concerned so even the addition of inert chalk will pass as lime. It's all smoke and mirrors with NHL. So it's not a question of 'higher' gypsum, it's a question of it's inclusion. Put simply, it should not be there.
When you mix NHL with lime hydrate do you add water to the hydrate beforehand so as to make a "putty", or do you mix it all at once? Thanks for your videos.
It's OK, there's no need to put the word putty in quotation marks. I understand what you mean. No, you just chuck it in. Remember, it's mainly for extra workability when plastering - not pointing. Unless extra workability is a requirement.
Hi, i am trying to replace some of my lime plaster walls from the 40s. I cannot find quicklime. All I can easily get is called hydrated lime at an agriculture store. Can this be made to a lime putty by mixing with water in paint buckets? I believe paint buckets are pretty air tight. Thanks.
You can but there's no guarantee of freshness. Not fresh = instant failure. And the workability and finish won't be as good as other limes.
I have found some quicklime I can get. I believe I should make it into a slurry with water and leave it to slake for three months. Then I will have lime putty? Also will paint type buckets with lids work? Thanks again.
@@standleyt Yes you can slake the quicklime to a putty if you like and leave it for 6 months to mature for top coat plastering. But it's not something I do. I'm not expert concerning bucket lids. So I can't be very much help with that question. I'm sure there are plenty of tubs with lids on ebay.
I thought you said that you slake your own putty. If so, what method do you use? I think the initial heat will melt the plastic bucket. Thanks.
@@standleyt I slake my own lime but it'd done as a hot mixed mortar. And yes, you're right, it would melt a plastic bucket.
Thank you for this video - it comes at exactly the right time! (That is, as I am trying to understand the various lime products available here in Austria.)
Just one question, if I may: Why does mixing lime hydrate with more water not produce "real" lime putty? Or did you just mean that it still needs to sit for several months to mature?
The chemical formula is different. Lime hydrate is calcium hydroxide but lime putty (which is fully slaked) is calcium oxide. Lime hydrate is not as good as lime putty. The finish ain't the same. It's also a different white. Very white. Which means mortars are very very light indeed. Looks different to other limes. FYI: Otterbein is made in Deutschland.
@@michaeljamesdesign Forgive me if wrong in saying the expansion and heat you create with kibbled lime is a benifit you like having rather than hydrated bag lime?
@@295walk I've just slaked half a bag of quicklime I've had lying around for a couple of years. It was second hand when I got it so it's probably about two and a half years old. And it's fine. You could never to that with lime hydrate.
This was my question, as well. Twice in the course of the video Mr. James mentioned the unsuitability of lime hydrate--but it wasn't until his reply to this comment that he actually explained the reason, or at least partially explained it. With all due respect, that's a flaw in the presentation! Especially considering that a lot of us live in areas where lime hydrate is the only lime to be had.
@@gungadin164 I'd say it's less suitable for me but I'm not the blueprint for everyone else. Hydrate was very popular hundreds of years ago and it's a useable product today. And as far as flaws are concerned: I could pick holes in this monologue all day long
Hey Michael thanks for the presentation. I have a question: is there a reason why you seem to slake your quicklime at temperatures exceeding 100°C?
Happens naturally.
@@michaeljamesdesign I read a paper that studies the properties of lime-mortars in relation to the type of slaking that was used. The paper concluded that air-slaked lime yields the mortar with the best qualities. That conclusion took me by surprise.
I work with powdered quicklime exclusively and I find that slaking is not always a super straightforward nor consistent procedure. Sometimes I add a certain amount of water and it heats up immediately. When I add the same amount of water to lime from a bag that had been open for a few weeks, the reaction is much slower. It takes 5 minutes before the water warms.
Another thing I noticed, I always make milk of lime which I add to my earth mortars, is that if my water boils during slaking, the lime will clumps together. Apparently slaking above 100°C creates crystals and reduces the plasticity and surface area of the lime particles. Industrial slakers are recommended to run between 80° and 90°C. The close the lime is slaked to boiling, the higher the quality of the slake. But over 100°C and there are diminishing returns.
I prefer to make milk of lime and not exceed 100°C also because there won't be any toxic fumes, which is an important consideration for as I often have to mix indoors.
Just some of my observations!
@@DeWarmePlakker I find the same with lime which is getting a bit older. But usually it's got to be a couple of years old before the slake time increases. I made some lime wash a while ago and it set sold after I was stirring for about 5 minutes. I think the amount of moisture in sand might have something to do with how much water we use. The brand of lime is important too. Calbux is immediate and instantly hot, but Otterbein and Lincolnshire chalk lime take longer.
@@michaeljamesdesign I use Supervical from Carmeuse here in Belgium. I'm quite lucky it's an agricultural product because I don't think I would've found any quicklime in Belgium at all!
tanks Mikey, bloody brilliant
Mikey 😅😅😅👍
@@michaeljamesdesign it was a fascinating and amusing piece. This lecture and Nige's presentation in the Holy Land (parts 1&2) are, I believe, the most informative audio-visual references currently available to mankind, in terms of Lime and its correct use - precious resources indeed! Merry Christmas to both you and Nige!
This is full of information to those who are knowledgeable already. I am not in the slightest suggesting Michael James does not have huge experience and knowledge but as with many books as far as I can see its so subjective.
It is using the terminology of centuries past, we might as well be referring to bushels , quarts and grains etc.
Its like listening to a shaman discussing mixing frogs, newts and snakes to make magic potions.
What is needed to bring the use of "lime" mortars , putty or what have you into the modern world is some absolute information. Some chemistry, some mesh sizes, grams and Kilogrammes in a table. End of talking about natural hydraulic lime , lime putty etc. w/o the chemistry and production mix definitions. Its like trying to understand Hungarian... for many .... maybe its just me?
Much of what we have had to go on to help us understand the way lime was used historically has all been bushels, sacks, pints and gallons. Aged recipes refer to aluminum sulphate as alum and it's expected of those who work with limes and colour-washes to know about traditional terminology. It's to be understood that a pint of ale can be used as a mordant and that a high clay content sand can be used to help set a lime mortar. How much you use is up to you because lime is all about feeling your way. It's like learning braille or swimming. You can only science it to some degree because it's a very inexact trade. But it's like all traditional trades and crafts, they all stem from knowledge gained many years ago and you learn by taste, smell, feel and sight. What works for one person in a particular environment might be a big mistake in another. What does work though is research. There's a lot of doctoral research which has provided evidence enabling us to understand historic mixed. Particularly in places like Israel - see Nigel Copsey. It's all out there and isn't too difficult to find - if you're prepared to do your spade work. If you joined the Building Limes Forum or searched for academic articles written by Dr G. Lynch then you'd certainly be able to understand lime plastering from a mesh size perspective.
@@michaeljamesdesign Thank you for your reply, I'll look for those links you mention. One aspect of all topics with extensive arcane language and terminology is that for experts it is so difficult to "unlearn" and see something from the position of the totally ignorant novice. This is where a good sciency reference book would help. It may exist but I've not found it. This does actually apply to ordinary cement mortar mixing too.
@@ianwhisson8064 You'll never get a good sciency reference book for lime in the same way you won't get one for roofing. But you can buy Dr G Lynch's books on Gauged Brickwork. You can also can buy N. Copsey's book on hot mixed mortars on Amazon. That's written off the back of a Masters dissertation. You can assemble a small library and that'll give you a start in the trade. Same for plumbing and electrics but if you're really intersted then go and do a practical course. What you're trying to do is the equivalent of trying to master the English language fluently after having only learnt English grammar. Learning just doesn't work like that.
Can you paint over a small patch of NHL 3.5 with paint?
Bit of a general question so generally, yes.
Internal 3.5 should I use soft or hard sand? @@michaeljamesdesign
Have you burnt any limestone yourself ? That would a good video and the lime cycle . Thank-you great video now i can understand more .
No but Nigel Copsey has. He's on youtube.
I’m in an ongoing process of slaking a load of lime putty with quicklime for top coat plaster. I know they say ideally it wants to mature for at least 4 months before use. I’m going to hold off using it as long as possible but if I have to use some of it fresh will it still be ok? How does the maturation improve it exactly? Is it purely workability or will the end product be affected?
powder, lump or kibble?
@@michaeljamesdesign Powder
@@Terrahawks_Zelda there aren't any lumps to mature in powder so you can probably use it after a few weeks. The longer you leave it the more the lime breaks down.
@@michaeljamesdesign Thanks Michael. Wasn’t sure if it was a usability i.e textural issue or a chemistry issue. Cheers.
Is all quicklime pure lime? Does it need to be non-hydraulic pure lime to be true lime putty?
Also you never finished your recipe for a “really good plastering mortar” because you got distracted by talking about how expensive and perfect pumice was, would you share that with me please? With and without the pumice/hemp?
There's not really any such thing as pure lime. But CL90 is about as close as you'll get. You need quicklime for lime putty.
@@flextacular6098 Which coat?
@@michaeljamesdesign 32:28 whatever you were saying around here
@@flextacular6098 I believe I was talking about thermal plaster with the addition of hemp and pumice and that I'd happily use pumice as an aggregate instead of sand but can't afford it.
Thank you
So many questions. I own a company that specializes in historic masonry restoration in Virginia. Would you be up for communicating by email? I don’t think this format lends itself to the detailed questions I’m dying to ask.
Give it a go anyway?
I’m also full of an eternity of questions up here in Canada , living and working as a stonemason in an historic town full of 150plus year old stone buildings.
How do you rate ionic old white 3.5 cheers
In what respect?
@michaeljamesdesign is it any good.
Would you use it and if so why
@@leemills1357 I've used it but only for colour. It's just the same as all the rest.
@@michaeljamesdesignbecause it makes a cream mortar?
@@leemills1357 This is the kind of subject your supplier should be telling you. It's made with argillaceous rock so this will always influnece colour in the direction of grey. Respectfully, you really should be in dialogue with your retailer. What do they say?
Well done!
What company do you buy your quicklime from?
It varies depending on the circumstances. I use lots of different suppliers.
@@michaeljamesdesign how do you work out how much pozz
@@Jameschris18819 Like this: ruclips.net/video/hAV9dGcVq94/видео.html
these explanations were clear as lime putty.
Well hush ma mouth!
thank you so much foe this video.
I suppose I'm wiser about the lime materials, but I still wouldn't have a clue about which ones to use for a given task.
thanks. i did last 52 minutes..i shall mix some hydrate into nhl tomorrow.
Well done.
I got the badge and would get th t-shirt f sure, the times my partner walks in while im cooking or sipping some green wine and she says "you watching this guy again..!?" Hellas..
Very useful content thank you, we are reviving an old house in SE Portugal, most of the stone work is schist with lime rendering and pointing, at least what survived the last round of renovations that include whole walls in cement render..
Question: all of the original render/pointing has been done with a medium brown lime, coarse/ish sand, no hair, but it's brown or latte color. across the boarder in Spain I have been able to source hydrated lime that is latte colored, but it's a CL70, is this dogshit?
we are just using it for plastering to mix & make the Secil lime warmer really, but Secil is the only stuff we can get our hands on.. there is some Keracoll stuff too that is 3.5 but comes as a ready mix and it's 20£ bag.. "breathability miracle" they sell it as..
The local builders use only NHL5 mixed with cement to tell clients it has lime.. it's sad to watch..
The brown lime plaster may even be earth/lime. There's still some around. CL70 is fine but you'll have to be careful slaking it as it's usually got a slow burn to it so you can easily drown it. Never buy premixed NHL because that's the dog shit stuff. NHL5 mixed with cement is just really bad. They don't need any cement whatsoever. "This guy" 😂😇 Ha ha!!
Well that cleared everything up
So it's still as clear as mud then.
I watched the entire video, thank you for the information. I live on the east coast of the US in New York and am a mason. In my area we have some brick homes built with lime mortar. Typically the brick are very soft and easily affected by freeze thaw cycles. We are also very limited on what is available for NHL, forget about lime putty or hot lime. I found a place about 4 hours drive away that is selling NHL 2, 3.5, 5, I have a customer that wants there brick home repaired using their original brick and lime mortar could you suggest what I should use? I realize you haven’t seen the house and the question might not be answerable. Thank you for what you do.
Questions: what's the weather like and with what were the units originally pointed.
@@michaeljamesdesignThe summer gets up to 95 degrees Fahrenheit, wet mostly, winters go to 20 below zero Fahrenheit at max now, used to be colder and more snow.
The units were laid in a lime mortar and fine sand, they didn’t have Portland cement here when it was built. It’s very soft.
you didn't finish your thought about what to do use on a north wall in the winter...
Plenty of pozzolan or NHL mortar.
@@michaeljamesdesign I have Secil 3.5 - thanks!
"once this lime putty has been allowed to mature for a while, you then have lime putty"
Oh dear, my bad. Did I really say that. I should've said something like 'Once this lime putty has been allowed to mature for a while you'll have mature lime putty'.
@michaeljamesdesign it made me laugh, brilliant video though. Full of insight and knowledge
Related to John Lennon?
Been doing this, historic masonry restoration, for going on ten years. And, it went from almost no info and research and/or availability for materials in the USA. And, it has exploded in the research department, still mostly overseas, of course, but availability has gotten a little better.... it's still a little hard convincing officials on anything other than portland cement here. It's bogus.
You guys must have access to quicklime out there though as it's used by farmers to condition soil. www.mlc.com/products/quicklime/ It's probably miles away from you but anyone who can get quicklime in 25kg bags or even buy it in bulk bags and containerise it has a viable business.
@michaeljamesdesign negative goodsir. They used pulverized garden lime. Aka. Crushed limestone. Non hydraulic and non-reactive. Quicklime is considered hazardous. And, was nearly impossible to order anything over around 1kg from an industrial supply storehouse. Until a new restoration importer opened up shop last year allowing us access to quantity weight of kibble (quicklime) and even 30 yr aged lime putty from Italy! Woohoo. Guess im back to buying kilos again, only never thought it would be of the masonry kind.... guess prison didn't teach me anything the last time.... lmao
@@IannoneBuilding There us one more possibility and that's to do what we used to do which is to build a small kiln in your yard and burn some limestone. Nigel Copsey has had some success with home kilning.
@michaeljamesdesign ive actually attempted to fire limestone four times. On the last time, I reached the nearly 2800 degree mark for an hour and was so excited.... but, I noticed when I finally unloaded my lime a strange sulfur smell and knew something was wrong... but, i tested it anyways... taking a small amount and adding a drop of water... no reaction. I thought what the hell now!?! Then, I had a random thought of that sulfur smell... and, I quickly googled the formula for gypsum.... and, wouldn't you know, the fine 100% all natural high purity calcium chalk I used, was not actually chalk, but gypsum! I was devastated because firing large quantities of the fine powdered garden lime proved troublesome as to obtain the temp supplemental air is required (for a small campfire sized pit), and with powder, poof, gone like a fart in the wind. Second attempt, I welded a contraption that solved the blowing away issue, but instead ended up with so much ash, charcoal, and foreign matter in the end product it was useless.... and, the metal surround reduced the amount of heat exposure to the lime. Attempt three, adjusted my contraption, solved the debris problem, but couldn't get high enough temp for long enough due to wet wood. And then I switched to chalk because It was much easier to handle, lacked the problem of blowing away and even if debris got in, the chalk pieces were easy enough to remove. Just a little post fire sorting party. Lol. 🥳. And, I the stage was set, had dry wood, charcoal for the bottom, and an open enclosure. The flame was white, the chalk was glowing, which made me smile as you know when you've got the good stuff when your limestone glows luminescent usually. So, i was excited as a pig in shit, even recorded the whole process post-glow. So, you get 20 mins of me explaining and with a child like Gettiness. And, then, no sizzle... cue insane cussing rant of epic proportions at 5am, in suburbia, and....that video was erased from existence out of utter shame and devastation. Lmao. So, it's a work in progress, plan on trying again when I can get my hands on enough free limestone or "real" chalk!
Very interesting. I did watch the entire video, however, I did get confused with all the different lime terminology.
I would appreciate, shorter videos then re- watch this one.
Very vague. Quick lime is Calcium Oxide. Hydrated lime Ca(OH)2 is lime putty. NHL has impurities which cause the lime to harden much more rapidly than pure lime and comes in different grades. You can turn hydraulic into non hydraulic by adding a pozzolan powder.
I think what you're trying to say is that you can add pozzolan to non-hydraulic (air) lime to give it a hydraulic set.