I'm a carpenter who has built several homes over the past fifteen years. I now spend my winters in Brazil, developing sustainable plans involving timberframing, cobb, and other local building products. I am so happy to see that conventional building practices and structural integrity are being championed in the bioconstruction/ sustainable building arenas. Foundations are incredibly important, and I've seen a few structures (two story cobb and timberframe) built on DRY STACKED STONE! I am not even kidding. One problem with groundwater, or heaving clay, and the whole building would be in jeopardy. Thanks again for stressing the importance of solid monolithic foundations. There's a reason building codes require these, and the weight of cobb (I build with extra thick walls in order to store the sun's heat like a battery) in addition to the huge timbers (25cm+) requires at a minimum thick pedestals for small houses (15m sq. cabins) or conventional footings for anything bigger.
What about a trench lined with river rock then polyurethane and then stacked rock? Wouldn’t that allow for drainage which concrete wouldn’t? Sorry I’m a total novice if this is a silly question.
Stone is great, but like you said no one knows how to do it. Where I grew up we build cob over stone but they've been mastering building with stones for hundreds of years.
@@flowergarden1426 I'm young and found out about cob while watching videos on my phone. I'm sorry you're so bitter and grumpy. There is a bright future ahead of us, and there are smart youngsters. If you bash them instead of teach them, they'll turn into you :(
@@maartenlaarhoven160 you got me all wrong, I homeschooled my kids and they worked with Cob and strawbale, volunteering, because I took the video games away. Glad you used your phone for something productive, happy to hear.
You prolly dont care but if you guys are bored like me during the covid times you can stream pretty much all of the latest movies and series on InstaFlixxer. I've been streaming with my gf these days :)
I have finished building a two story house in Cob the traditional English way on a rubble trench foundation. It is vital to understand the importance of drainage to any building and you ignore it at your peril. Concrete is not stable and to advocate its use over the proven rubble trench is just downright irresponsible. If you hire an excavator for two or three day's you can cut your level and dig your trench, done. Then all you have to do is back fill it with stone rubble of the same size as railway ballast and your done. It's not hard and it's relatively a helluva lot cheaper than pouring tons of concrete. The stone plinth only needs to be 12" to 16" high to do its job. The beauty of the rubble trench is that it permanently isolates the earth inside and keeps it dry. Concrete does not.
Thankx for all the infos on your channel! I built a cob house with my dad in 93-94 and we used concrete trenches as a foundation. We could have used stones instead, because the farmers in our area are happy to get rid of them, but you need skills and time for that. Greetings from northern Germany!
It always strikes me as funny, with all this amazing return to ancient knowledge... we spent hundreds of years trying to move away from these methods, only to realize that almost all of them were perfectly fine just the way they were. Edit: or better yet, that they were valuable ways of building that provide solutions to our housing and climate crisis and with funding and science backing it, could evolve till we build incredible structures that are both durable and can cater to a wide range of lifestyles.
Actually you will find a lot of methods for earthen housing are not employed because in the western world time/man power costs more than material components. It takes longer to build a structure of cob and more man time than it would with premade modern building components. if you are paying for a team of builders and you only used cob methods in the UK (where I live current). it will cost you more in building time. If you were building it yourself no time constraints however and your labour isn't what's costing you on the other hand- you'd be a fool to not look into this since its the budget difference is going to be out of this world for your main building material. Edit: I have no problem with concrete being used in a home no matter what the intent was for its design. however, to stand and say "concrete is just the best because it is" is REALLY naïve, I've seen plenty of examples of great cob housing that does NOT use concrete foundations that has stood solid to the test of time. Concrete is the easiest method with the fastest results, if time and effort is a factor then that is what you are getting this for, you can get the same results with stone but it will take more effort and skill to get that result and more room for error which can effect the result.
My dad was 40 years in the concrete industry. This video was very well done and I appreciate your attention to detail and emphasis on the importance of a strong foundation. Well 👍 done!
Thank you for actually talking about foundations and why some are better than others, and how different approaches solve similar problems effectively if you actually understand where you're building--for example why earthships work in desert but in temperate places, not so much. I've also been bothered by the recycling-over-engineering vids made by people who seem to be just experimenting without any understanding of how those bags degrade, or foundations might shift, or what the frost line is and why you have to sink a footer below it. I'm glad they've rediscovered their inner child, but I don't want a five-year-old building my foundations.
Experience and history have demonstrated that the concrete footer upon which the stem wall rests (in the illustration), could be replaced by crushed and compacted stone or rubble. This way, the "frost line" becomes immaterial because it has insignificant effect on the stone rubble foundation. Also, experience and history have also shown that imbedding steel rebar into concrete will decrease the longevity of the concrete, as the steel will eventually oxidize causing spalling, fracturing or both. Yet, despite this real-world evidence, most AHJs will be looking for steel rebar to be installed. Why? From information gleaned over the decades, it appears that most soils in North America, will support the majority of what passes for home construction. Get your soil tested if in doubt and yes pay attention to the materials and installation of the foundation components. This is not the area to "cut corners" but it is also foolish to "over engineer" the structure based on modern building "traditions".
Amazing, I was literally thinking of foundations today and boom, here's a video! Two appeals of not using concrete can be wanting to reduce CO2 footprint and stone if easy to source can be cheaper. Certainly what I'm considering. Then philosophically there's a bit of a disconnect for me to have >50% of your building be concrete and then a bit of cob. At that point, why not have a fully concrete house? What would you think of a concrete footer with stone wall above? Or cementing the interlocking stones together? I'd love to hear more about stone foundations! I'm not saying you're wrong, just my thoughts on it and I really appreciate the time you've put in these videos.
Sure! I'm still a big fan of stone foundations, but I don't think most people are in a situation to viably do one properly. This is a big reason why I talk people down from them a lot. But yes, I think a concrete footer and a stone stemwall would be great overall.
@@boringusername792 Most stone foundations I see done by DIY builders are completely wrong. They don't know how to stack stone properly. Its an art form that can't be slapped together by unskilled laborers. Stone is not monolithic, its almost impossible to get code approval for, and its generally more expensive than concrete. I do like stone foundations, but it presents many challenges.
I have a degree in structural engineering (not licensed). I'm 100% on board with concrete footings and foundations for cob walls. But so long as the wall foundations are tied together, strictly speaking you could really do away with the concrete slab floors, at least from a structural point of view. Have you looked into options for rammed earth flooring? I'd be curious what you think about that. I don't have experience in this realm. It seems like a way to save a considerable amount of cement. I just found your channel yesterday and I'm really enjoying it. Thanks for all your hard work.
Hi! Thanks! I've given a bit of thought to the rammed earth floor. I think it would be challenging to make the floor tamped perfectly flat. But I've never tried it! Maybe it could be self level at the end with some sort of natural resin?
Do you think those metal cages that they use along the sides of road embankments that are filled with rock chunks might work as a form for a strong flat raised floor maybe using rammed earth and that if the floor is held together well enough with the wire, stone and rammed earth so that it doesn’t shift then the metal might be able to be connected from the floor rock cages to the hay bales wire mesh stabilization system with more wire and the whole thing might be interlocked with the wall and the floor as one unit and as a bonus it would have built in easy drainage with it holding a bunch of farm field rocks and I’d probably build a wide Roman concrete wall base sill around it to below the frost line to put the straw bales walls on, I saw somewhere that Roman concrete stuff fixes itself if it cracks a little and, if it gets damp again after it cracks the water fixes the crack, if it works out it might be pretty good and on top of that it’s supposed to be much better at insulating than regular concrete is because of the volcanic rock in the recipe. I haven’t looked at the prices on that Roman concrete mix, or the fancy building reinforcement wire, but hay bales and mud are definitely still in my price range if I can ever find a place I like where I can afford to build a house. I hope that makes enough sense, it’s late and I can’t keep trying to edit for clarity because it just isn’t working and every time I change one thing it makes other things worse.
I wish you would have made a bit more of an argument here. I still don't know *why* I should use concrete besides 'concrete good, others bad'. Maybe a least mention the cons like concrete's huge carbon footprint and non- breathability. It is strong and stable, yes, but that doesn't make its use sustainable. And if strong and stable is what you're after, try urbanite (recycled concrete) and brick with a lime or concrete mortar in between. Over all, oddly polarising video and, unless you are already set on using concrete, not very informative.
Sustainability aside, concrete is the best option for most cases. Urbanite and brick are fine options, but have the same drawbacks as stone (non-monolithic, difficult to pass codes). Breathability isn't really an issue with foundations. As long as you are not putting a concrete plaster over your walls, which I would never recommend, your earthen walls will be breathable.
@@thiscobhouse normally I like your vids, but this commenter is right. This video is very weak. You cant just toss aside sustainability. Thats the main reason people are looking into these more natural building techniques. Second is saving money, and really these natural building ways arent cheaper after you factor in time and labor costs. Pretty much breaks even tbh. This video is what chases subscribers away because its obvious to see your closed minded and don't care to explain things that you don't agree with. Terrible look.
@@BradleyWileyOUTDOOR-MAN Yes, I don't like to use certain alternative materials. Its not because I'm closed minded. Its because I've used them and studied them, and they don't work as well as they are professed to by many sustainable builders. I'm not trying to please everyone with this video. I'm just speaking my mind.
lets pretend this isnt 2 years old. He made the most explicit and effective claim for why concrete is prime. THE SHIFTING OF THE EARTH. One does not simply ~will~ science away. For your safety and to the thumbs who are arguing about this, may you choose an objectively correct, uniform foundation
As someone who works for Earthship Biotecture: Tires can work great in any climate :) Also, not liking concrete isn't stupid or ignorant. The energy it takes to make that stuff is awful. Obviously a great building material though.
Thanks for explaining things so well and being so honest. I wish concrete weren't used anymore but you're right that the alternatives are risky. Would you recommend any resources so I study how to build a foundation myself? I want to save money as my budget is limited. Many thanks!
From my point of view and few cob house,mud house i builded, bed rock or big rocks is the most thing possible to replace concrete but it require high skill to put it on exactly and quite expensive, and use high labour to work with, and if you dont do it right, it'll easy to shake and colapse, it's easier when put cement or lime between the rock to make it harder and stand well together, but the problem is most of the world pollution not come from concrete or cement, it comes from agriculture, castle raising, and a part from vehicles and some industry needs to burn things people need usually more like steel, electric or plastic,etc.., But now if we just use cement and concrete for only the foundation, it'll even less more pollution for the construction activities but still make your house SAFETY for yourself but it'll not create much change in decrease world's pollution right now. So from my point of view, i'll just keep use concrete for the benefits of it, while planting more trees ,eats less meat, and use less more things and energy it'll better for environment and create a safety house for you.
I'm glad I came across this video. I keep seeing videos using dry stacked stone and I have no access to (free) stone because my land has literally no rocks anywhere and I'd have no knowledge of how to stack them confidently. I'd rather use concrete block or poured concrete for longevity. THANKS! I would like to build a cob house on top of a full basement which I'm trying to figure out.
I agree! There's little to no good stone in my area, and getting it would be expensive. But knowing that concrete is a good option frees up so much--especially when it comes to putting in a basement, which I really want! It would add so much space to put one in.
How about something middle of the road, like rubble trenches? it is a medieval technique where you dig a trench, install french drain at the bottom(draining on a lower part of land by gravity), fill the trench with potatoes size rocks . Lower footprint since rocks are stacked in a trench up to ground level, then you start a small concrete wall for a crawlspace. No basement. but solid and stable as it can get.
@@thiscobhouse Of course, but a lot less material than a standard footing+full size wall. In fact it could take more or less the same material than a standard footing.
I've wondered for a long time about the stability of the tire wall. The Earthship concept is really cool. But the creators seem to priorities recycling over building a solid building. Like putting the cans in the walls. To me thats a bunch of week points.
Maybe utopia and recycling necessitate each other? We are not being given tools for self reliance, recycling, utopia. We are being given throwaway products that require specialists. Some of us would rather make long-standing beauty with the least effort, the least impact, even as we make mistakes @@neatcool4770
we are thinking of building a cob house, and our land happens to have quite a bit of stone. Would you think it would be a decent idea to throw some large stones in the bottom of trench that goes below the frost line and pour concrete around it? It just feels better to use as many materials I have on hand if I can without compromising stability.
Yeah this has always been a question I’ve wondered about too since all the little rocks you collect can just get thrown in and embedded in poured concrete and fill up space, saving money and resources.
THANKS FOR VIDEO! would it be hard for me with no experience to build a concrete foundation? Or if I had to hire someone...Is it expensive to build a concrete foundation? Thankyou
If I'm going to put in the work and creativity into building my perfect cob home, I'm not going to risk it cracking and crumbling because of shifting. I would still be building a home for much cheaper than conventional style if I invested in a proper foundation. Foolish not to; especially if you want it to be a forever home..
@@thesoliloquist1940 Cold and wet is not a problem for cob if the building is constructed properly. Cob does not have insulation though so you will need a good heat source inside your building if you have cold winters.
Hello, Im building in Gambia an been watching your videos to help, and thank you so much these videos are amazing! Could you use cube wire cages with stone for the foundation and pour concrete to create that one slab effect? save on concrete (although dont want to skips corners) a what are your thoughts on this?
Concrete is one of the main products that is difficult to recycle. It accumulates during demolition. Concrete will always crack and expand. To protect the ground of your home, you can lay a moisture barrier sheet and use gravel and/or broken concrete. You can fill in gaps with cob mixture or concrete and water. If you are in an earthquake prone location, it would also be a good idea to add a steel plate border.
thanks... yes, more info than many vids out there. I live in the Sacred Valley of the Incas, so stone is plentiful and used fairly often... but even here, many people use cement/rebar with adobe for homes, and the precise stonework that you see in Machu Picchu and other ruins, is hard to find.
Have you done any timber frame earth homes before? I’m going to be building a timber frame cabin and I’m hoping to use sawdust as the walls. It’s a fairly small cabin around 14x 16. I’m having a hard time deciding on how to incorporate the foundation for earth walls and timber frame. I’m thinking I’ll build the walls up on a pony wall and have the timber either on footings, possibly attached to the pony wall. Or should I just build an extra thick pony wall? Any suggestion would be greatly appreciated!
I love the look of stone, but sounds like concrete is really much more practical... what about poured concrete foundation and a stacked stone façade around the base of the house? Using concrete to adhere the stone to the wall.
I have a huge existing concrete base so does this help me start my small cob garden den I’m here in uk, I have free timber and I’m on clay soil with tons of straw around me so I’m saving on any new materials?
I found this pretty informative, what I don’t completely understand is if you have a “hollow” foundation. As in when you show the foundation components, I can see the earth underneath the flooring layers. So is the foundation made only for where the walls will be build? And then I can see you pour it on surface over the ground, can you detail more in a video exactly where is there a foundation foot and where there is only a thinner layer? Thanks a lot, I don’t know if you will see this comment after 10 months from posting the video.
I'm building a potting shed in the garden out of cob. As it's not really a permanent structure that I will be living in could I build the cob walls on concrete paving slabs or do I still need deeper foundations? The roof and wall posts are wooden.
I live in south carolina. Would the moisture out here effect any possibility of me having a Cobb house in these parts? I ask because it rains alot out here. Just wanted to know. ..and if it is possible to own one, what foundation would you recommend for South Carolina? Love your videos and thanx!!🤍
How do you join the interior flooring concrete (and other materials shown) with the side of the stem wall? Is it enough to pour the concrete or cob on top of the floor insulation or should we bond those materials some how to the foundation at the cross section?
im curious about something, what if you dont need to worry about freezing as i live in an area that does not freeze rather there are tremors occasionally and personally for me its just easier to do a concrete foundations as there little to none broken stone or cement unless your haunting a build site, id rather be building my own lol thanks for the video
Great video, but i have a small Important question. Is Frost can lift up the gravel or stone when they put it on the frost line ? Or we need to mix and pour lime or cement with sand after we put the big rocks down there. But how about the gravel people use in Rubble trench, Frost could lift the gravel up, right ? So, the only good possible foundation is concrete below the frost line, and the gravel below the concrete to get good water drainage ?
When I see concrete, it always seems to have cracked from thermal expansion/shrinkage, to the point that pavers put those deliberate divisions into the sidewalk to break up the monolithic nature of the material and allow it to expand and shrink without cracking. So, if you'll pardon the noob question, why is a monolithic concrete foundation better for building than stone if it breaks under temperature changes? (hell, the same could be asked of cob, though i figured it'd be more "flexible" what with being heterogeneous and permeable?)
Hi, thanks so much for these videos! I was wondering if you had heard of the “carbon-neutral” cement developed by Sublime Systems out of Massachusetts? I don’t know anything about them beyond what i heard on their NPR spot a few months back .. or about cement beyond laywomen use, but it sounded like they have made cement that is chemically and structurally identical to the original stuff but found a way to produce it at scale for similar prices but with way less energy used.
Thank you! It’s November 2021. Am interested in attending one live seminar this coming summer. Please provide me with a link to go to for signing up. Great work!!
Hmmm.. Well, concrete is mostly just a mixture of crushed up stone and cement binder. You could use lime based concrete for mortar, but I don't think it would hold up as a poured monolithic foundation. Modern concrete is 99% natural material though so its not as bad as people think.
@@thiscobhouse Okay, thank you! Well, I have heard before the modern concrete doesn't hold up as well as roman. I wasn't sure if this is true but personally I put a lot of trust in ancient methods of building, but that is just my opinion.
Can you put up more videos being more detailed aboht foundation. I see alot of things in video that id like info on. For example .. That is the pink part of foundation and what is its purpose..
I do enjoy the look of the old stone foundations. I wonder if trekking over to the UK to learn from master masons that are still around; they could teach on the stone foundation construction of the their 500+ year old cob buildings... would be lovely if feasible. An art form such as that should not be lost. Your concrete foundations do look nice though!
What about condensation points and other moisture issues?? A cold material like concrete or steel rebar could cause mold if it's in direct contact with natural building materials, right?? I live in Massachusetts.
@@thiscobhouse I recently watched a video about this. A woman explained that there is moisture in liquid form and moisture in gas form. Her argument is that liguid moisture is bad. You want to keep it out, or else you get mold and rot and expensive replacements. While moisture in gas form is good. You want it to have full access to your entire building. That way the humidity and air quality inside the building is regulated by the building itself. I thought it fascinating.
@@thiscobhouse And your video also makes me ask myself more questions about concrete too. Are there ways to reduce CO2 emmisions in it's production?? Reducing the amount used with rubble foundation sounds a good idea. But also, could there be alternatives in monolithic form?? As you said, concrete is mostly natural products. If it is so similar to natural products, could there be a way those concrete-like products with a lower footprint be used?? I'm thinking something like rammed earth. Speaking of tires, I've been told in England they use tire bales as foundations for highways and other road projects. It's drains the foundation as well. So much to unpack here!!!
Yes, I think a concrete/masonry foundation would be great for that. You don't have to for a chicken house though. It just depends how nice/long lasting you want it to be.
While you are constructing the foundation and the infrastructure, could one start making cob bricks or blocks lg/sm, so when it comes time to build walls most of the mixing and drying is already done? Just put the blocks in place and fill in the gaps with fresh cob. I know it's more complicated than that, would that save time in the end to have most of the cob already made and ready to put in place? Will that weaken the cob wall?
What do you make of straw bale construction? It seems risky to me here in the UK with the damp. You see these middle class types move out from the city to the wilds and build them quite unawares of the fact rats can get into anything and if hay gets wet it can spontaneously combust. I suppose I just answered my own question.
We should have the COB Institute request random particle generation and simulation in the Physics Software like COMSOL and Altair. I'd like to see it for Tribo-Electric Charge (Static Electric charge) anyway it's not there yet. But probably not far off. They could then be simulated Seismically for Rammed Earth, COB, . . . I'd like to know how the walls perform under Transverse and Longitudinal Waves. The simulation of mud might not be far off of space dust and Clustering / Clumping Theory - Nebular Hypothesis. Not sure doubt anyone has done it yet. Oh one of the Mudgirls Structures stopped a tree. lol. That's pretty impressive actually.
Concrete is not the best foundation or the only foundation. Its just the expensive option and cheap option for manufacturers. Its easy and cheap for them but bad for the environment and read up and its water wicking.
In actuality, there are two camps, monolithic and floating foundations. Look at some of the tallest skyscrapers. While they are indeed concrete, the buildings are not directly tied to them in order to give the building a buffer from seismic movements. And in the same way on a smaller scale, we have rubble trench foundations.
I couldn't agree more, watching all these build videos the number one mistake I see are the stem-walls and foundations. I plan on starting a build next year and am going 100% concrete period the end. The last thing I will chance is having foundation problems or failure after spending all the time, money and effort it takes to build one. It just doesn't make sense.
Water 'can' wick up through a concrete foundation (or any foundation for that matter), but is very unlikely to unless you have some major drainage issues around your house, for example. The cob code does specify to put a water barrier on top of the concrete stem wall foundation to prevent water from wicking up into the cob walls. In my opinion, this is very unlikely to happen though. Its more of a fail safe measure. Even if some moisture gets into the walls, it will quickly dissipate back out before it can do any damage.
My understanding is that it is frequently used to replace up to 50% of the cement. I'd hesitate to go beyond that without doing more research. Don't over-water the concrete. Fly ash can make a stiffer mix so you may want to add a plasticizer rather than extra water. If you're getting a mix from a local ready-mix concrete supplier they'd certainly know what local code officials accept. If you're making it yourself the IRC 2021 code mostly allows for a minimum strength mix of 2500 psi (Table R402.2). Normally there's no need for more strength than that. So if you want to save on cement, don't make the mix stronger than necessary. On the other hand it's critical to keep in mind local conditions. Slopes, compressive soil, fill, expansive soil and a deep frost line are all things that should be considered.
What about aircrete? Could that be used for a foundation? I would like to build some cob structures on my property possible a home as well. I would really love to have an earth integrated home or completely underground. Is it possible to use cob for those structures? Also what about rain? What do I have to do in design to accommodate for rains? Or for underground if it's possible? Thank you for your time and assistance and all the videos. Truly appreciated!
Hi Leigh Ann, the aircrete mixes I've seen give a maximum strength of a little under 1000 psi. The building code for houses, IRC 2021, requires at least 2500 psi in most cases. So if you're going to go by code and get a permit I doubt aircrete is a solution.
Surprised you didn’t cover moisture and concrete. My concern is how much water may wick up through the concrete to cause moisture damage to the interior of straw bale walls, especially in cold damp climates. Not to mention the cracking of foundation walls due to the freeze thaw action in such climates.
Rising damp happens mostly with basement foundations. When foundations are sitting in a pool of water. Foundations could have this issue, especially in northern climates though since the foundations should be dug below frost line to prevent frost heave. Yes, these are concerns, but I think they pertain to all sorts of foundations.
Absolutely. Cement is hydrophilic, it soaks up water. This is why you have to have a membrane and very good flashing between it and any organic material. As for freeze thaw, insulation below and on the sides help to slow the thermal transfer to abate cracking. That said, I don't believe this chap has done enough homework to be an authority on the subject. I'd look elsewhere. And, I'd suggest looking into rubble trench foundations, that is if you're local building code will permit them.
People should know that concrete will harden over time and peak at 50 years then start to decay and disintegrate. If you ad fly ash to the concrete mix, it will last thousands of years. Just FYI.
Are you talking about fly ash as used in geopolymers? I would totally use geopolymer concrete if it was widely available. I do agree that concrete can disintegrate over time, and sometimes the rebar can expand causing spalling. But let's also remember that stone also will disintegrate over time. Especially soft stones. Thanks for your input! Good information to know.
@@thiscobhouse I guess it might be easier said than done to use fly ash but easy in my area as the power companies use coal at the power plants and the result from burning coal is fly ash. The reason there are roman structures around today is they used something similar and I think it was vulcanic pumic or something similar to fly ash. I totally agree with you about using concrete and definately using rebar. I would never build anything only using stone as a foundation.
Though I appreciate you addressing stuff like foundations and the effort it takes I found this video to be very one sided. Concrete has many wonderful things about it but it also has weaknesses. The fact it accounts for 8 to 10% of all CO2 emissions as well as that it is hydrophilic and porous. Concrete draws water all the way through its system. One of it's greatest strengths is that it's monolithic but its also a great weakness because this means it is very difficult to repair if there are any cracks in it. Concrete foundations built up to code often need extensive repairs after 30 to 40 years which costs tens of thousands of dollars. Concrete is strong being around 4000psi but its super weak in tension(considered negligible in design at 400psi) meaning there has to be steel rebar reinforcement in the tension areas. Unless properly treated a lot of this rebar overtime will get wet from the porous nature of concrete causing rust, expansion and then cracking which creates problems. I have taken extensive classes on concrete and just as they sing the virtues of concrete in traditional education there are definitely drawbacks to it. I think a better explanation as to why these other foundation systems are bad is needed. I found that there was almost no evidence provided in this video to support the claims made and know for a fact that there are many examples of foundation types other than concrete that have a good track record. There are many examples throughout the world of stone foundations much much older than modern concrete. As for stuff like earthbags, time will tell, but for sure there is evidence that they do not start crumbling by the time one finishes the tops of their walls. Are they good foundation techniques? I don't know and there hasn't been enough time or testing to show if they are or not. Please correct me if you think I am wrong about any of this. I love learning and just wanted to point out a couple things I felt people should know.
I think we would all agree that concrete can be a wonderful material in construction. Like any material, it can be misapplied or be of substandard quality. Alternative building methods which attempt to mimic or reproduce ancient methods are often void of concrete as a material. Can a viable foundation be constructed without concrete? Absolutely. Look at the ancient buildings still standing on nothing but stone. In the interest of keeping costs manageable many seek a building alternative more conducive to DIY. To call people "stupid" or "ignorant" because they hold a different opinion is somewhat caustic, condescending and adds nothing to the conversation. Simply, state your case and give the data (empirical or anecdotal) to show how you arrived at your conclusions. Others will consider it, or not. Just because a truck deposited tons of concrete at your building site, does not guarantee the foundation, slab or anything else will be issue free. Consider, how many times you have seen concrete being placed and then finished, only to see the crew walk away without addressing the curing process? Answer, almost always. Why? Because despite the common knowledge that "concrete cures best that cures slow", the contractors (or installers) make no time to address this fundamental and important key element.
I don't know much about cob building specifically but I've worked lots of blue collar jobs in my life. The fact that people would call you an idiot for recommending that you don't use bags or tires or individual stones for a foundation is absurd lol I can understand wanting to stay with tradition, but why stick with tradition if you can't do it properly and have easier cheaper more effective modern alternatives? I imagine an earthquake wouldn't be too nice to a house made of cob that's essentially one single rigid piece that's sitting on a broken up stone foundation lol
I hear ya! I don’t like concrete, but you can’t beat what it provides. Now there’s ways to work with concrete that most don’t take into account, like a slab with walls to have a floating wooden floor. However; haters gonna hate. You know your onto something with the amount of resilience you get
@@thiscobhouse This is a RUclips comment it is not meant to be exhaustive, sir. I appreciate your channel, and I am not opposed to cement, but I am just wondering out loud if once one factors in the relative longevity of a well made stone foundation it wouldnt up end up being far cheaper than cement.
Thank you for this video. Could i use earth bricks placed below the earth for the wall foundation in the same manner they are placed above the earth as my wall? It would be an 18in wide foundation, and using mortar to bind the bricks in the foundation to be more monolithic. I look forward to your reply.
I'm a carpenter who has built several homes over the past fifteen years. I now spend my winters in Brazil, developing sustainable plans involving timberframing, cobb, and other local building products. I am so happy to see that conventional building practices and structural integrity are being championed in the bioconstruction/ sustainable building arenas. Foundations are incredibly important, and I've seen a few structures (two story cobb and timberframe) built on DRY STACKED STONE! I am not even kidding. One problem with groundwater, or heaving clay, and the whole building would be in jeopardy. Thanks again for stressing the importance of solid monolithic foundations. There's a reason building codes require these, and the weight of cobb (I build with extra thick walls in order to store the sun's heat like a battery) in addition to the huge timbers (25cm+) requires at a minimum thick pedestals for small houses (15m sq. cabins) or conventional footings for anything bigger.
What about a trench lined with river rock then polyurethane and then stacked rock? Wouldn’t that allow for drainage which concrete wouldn’t? Sorry I’m a total novice if this is a silly question.
Stone is great, but like you said no one knows how to do it. Where I grew up we build cob over stone but they've been mastering building with stones for hundreds of years.
Exactly!
Take the video games and the phones away from these young people they will learn skills, what a shame this is a lost art.
@@thiscobhouse what area of the world do you live in?
@@flowergarden1426 I'm young and found out about cob while watching videos on my phone.
I'm sorry you're so bitter and grumpy. There is a bright future ahead of us, and there are smart youngsters. If you bash them instead of teach them, they'll turn into you :(
@@maartenlaarhoven160 you got me all wrong, I homeschooled my kids and they worked with Cob and strawbale, volunteering, because I took the video games away. Glad you used your phone for something productive, happy to hear.
"A good hat and good boots" ... A good roof and foundation are key for longevity of a structure.
Yes, absolutely true!
You prolly dont care but if you guys are bored like me during the covid times you can stream pretty much all of the latest movies and series on InstaFlixxer. I've been streaming with my gf these days :)
@Jamison Jude yup, I've been using Instaflixxer for years myself :D
I have finished building a two story house in Cob the traditional English way on a rubble trench foundation.
It is vital to understand the importance of drainage to any building and you ignore it at your peril. Concrete is not stable and to advocate its use over the proven rubble trench is just downright irresponsible.
If you hire an excavator for two or three day's you can cut your level and dig your trench, done. Then all you have to do is back fill it with stone rubble of the same size as railway ballast and your done.
It's not hard and it's relatively a helluva lot cheaper than pouring tons of concrete. The stone plinth only needs to be 12" to 16" high to do its job.
The beauty of the rubble trench is that it permanently isolates the earth inside and keeps it dry. Concrete does not.
Do you have a plan?
Thankx for all the infos on your channel! I built a cob house with my dad in 93-94 and we used concrete trenches as a foundation. We could have used stones instead, because the farmers in our area are happy to get rid of them, but you need skills and time for that. Greetings from northern Germany!
Super for all of us learners to hear from people with their own experience building cob. Thank you!
It always strikes me as funny, with all this amazing return to ancient knowledge... we spent hundreds of years trying to move away from these methods, only to realize that almost all of them were perfectly fine just the way they were.
Edit: or better yet, that they were valuable ways of building that provide solutions to our housing and climate crisis and with funding and science backing it, could evolve till we build incredible structures that are both durable and can cater to a wide range of lifestyles.
science seems more interested in artificial intelligence and transhumanism
And all without CONCRETE foundations, (until this guy)....
You never really appreciate something until its gone unfortunately
@@davidhayes5382 the sad irony of life.
Actually you will find a lot of methods for earthen housing are not employed because in the western world time/man power costs more than material components. It takes longer to build a structure of cob and more man time than it would with premade modern building components.
if you are paying for a team of builders and you only used cob methods in the UK (where I live current). it will cost you more in building time. If you were building it yourself no time constraints however and your labour isn't what's costing you on the other hand- you'd be a fool to not look into this since its the budget difference is going to be out of this world for your main building material.
Edit: I have no problem with concrete being used in a home no matter what the intent was for its design. however, to stand and say "concrete is just the best because it is" is REALLY naïve, I've seen plenty of examples of great cob housing that does NOT use concrete foundations that has stood solid to the test of time.
Concrete is the easiest method with the fastest results, if time and effort is a factor then that is what you are getting this for, you can get the same results with stone but it will take more effort and skill to get that result and more room for error which can effect the result.
My dad was 40 years in the concrete industry. This video was very well done and I appreciate your attention to detail and emphasis on the importance of a strong foundation. Well 👍 done!
Thank you for actually talking about foundations and why some are better than others, and how different approaches solve similar problems effectively if you actually understand where you're building--for example why earthships work in desert but in temperate places, not so much. I've also been bothered by the recycling-over-engineering vids made by people who seem to be just experimenting without any understanding of how those bags degrade, or foundations might shift, or what the frost line is and why you have to sink a footer below it. I'm glad they've rediscovered their inner child, but I don't want a five-year-old building my foundations.
You're welcome, friend!
Experience and history have demonstrated that the concrete footer upon which the stem wall rests (in the illustration), could be replaced by crushed and compacted stone or rubble.
This way, the "frost line" becomes immaterial because it has insignificant effect on the stone rubble foundation.
Also, experience and history have also shown that imbedding steel rebar into concrete will decrease the longevity of the concrete, as the steel will eventually oxidize causing spalling, fracturing or both. Yet, despite this real-world evidence, most AHJs will be looking for steel rebar to be installed. Why?
From information gleaned over the decades, it appears that most soils in North America, will support the majority of what passes for home construction.
Get your soil tested if in doubt and yes pay attention to the materials and installation of the foundation components.
This is not the area to "cut corners" but it is also foolish to "over engineer" the structure based on modern building "traditions".
Amazing, I was literally thinking of foundations today and boom, here's a video!
Two appeals of not using concrete can be wanting to reduce CO2 footprint and stone if easy to source can be cheaper. Certainly what I'm considering.
Then philosophically there's a bit of a disconnect for me to have >50% of your building be concrete and then a bit of cob. At that point, why not have a fully concrete house?
What would you think of a concrete footer with stone wall above? Or cementing the interlocking stones together? I'd love to hear more about stone foundations!
I'm not saying you're wrong, just my thoughts on it and I really appreciate the time you've put in these videos.
Sure! I'm still a big fan of stone foundations, but I don't think most people are in a situation to viably do one properly. This is a big reason why I talk people down from them a lot.
But yes, I think a concrete footer and a stone stemwall would be great overall.
@@thiscobhouse Cheers! What are the common pitfalls of stone foundations and what do people typically do wrong or not do properly?
@@boringusername792 Most stone foundations I see done by DIY builders are completely wrong. They don't know how to stack stone properly. Its an art form that can't be slapped together by unskilled laborers.
Stone is not monolithic, its almost impossible to get code approval for, and its generally more expensive than concrete.
I do like stone foundations, but it presents many challenges.
I have a degree in structural engineering (not licensed). I'm 100% on board with concrete footings and foundations for cob walls.
But so long as the wall foundations are tied together, strictly speaking you could really do away with the concrete slab floors, at least from a structural point of view. Have you looked into options for rammed earth flooring? I'd be curious what you think about that. I don't have experience in this realm. It seems like a way to save a considerable amount of cement.
I just found your channel yesterday and I'm really enjoying it. Thanks for all your hard work.
Hi! Thanks!
I've given a bit of thought to the rammed earth floor. I think it would be challenging to make the floor tamped perfectly flat. But I've never tried it! Maybe it could be self level at the end with some sort of natural resin?
Do you think those metal cages that they use along the sides of road embankments that are filled with rock chunks might work as a form for a strong flat raised floor maybe using rammed earth and that if the floor is held together well enough with the wire, stone and rammed earth so that it doesn’t shift then the metal might be able to be connected from the floor rock cages to the hay bales wire mesh stabilization system with more wire and the whole thing might be interlocked with the wall and the floor as one unit and as a bonus it would have built in easy drainage with it holding a bunch of farm field rocks and I’d probably build a wide Roman concrete wall base sill around it to below the frost line to put the straw bales walls on, I saw somewhere that Roman concrete stuff fixes itself if it cracks a little and, if it gets damp again after it cracks the water fixes the crack, if it works out it might be pretty good and on top of that it’s supposed to be much better at insulating than regular concrete is because of the volcanic rock in the recipe. I haven’t looked at the prices on that Roman concrete mix, or the fancy building reinforcement wire, but hay bales and mud are definitely still in my price range if I can ever find a place I like where I can afford to build a house. I hope that makes enough sense, it’s late and I can’t keep trying to edit for clarity because it just isn’t working and every time I change one thing it makes other things worse.
Thank you! This answered the questions I had about foundations. I appreciate your honesty.
I wish you would have made a bit more of an argument here. I still don't know *why* I should use concrete besides 'concrete good, others bad'. Maybe a least mention the cons like concrete's huge carbon footprint and non- breathability. It is strong and stable, yes, but that doesn't make its use sustainable. And if strong and stable is what you're after, try urbanite (recycled concrete) and brick with a lime or concrete mortar in between. Over all, oddly polarising video and, unless you are already set on using concrete, not very informative.
Sustainability aside, concrete is the best option for most cases. Urbanite and brick are fine options, but have the same drawbacks as stone (non-monolithic, difficult to pass codes).
Breathability isn't really an issue with foundations. As long as you are not putting a concrete plaster over your walls, which I would never recommend, your earthen walls will be breathable.
@@thiscobhouse normally I like your vids, but this commenter is right. This video is very weak. You cant just toss aside sustainability. Thats the main reason people are looking into these more natural building techniques. Second is saving money, and really these natural building ways arent cheaper after you factor in time and labor costs. Pretty much breaks even tbh. This video is what chases subscribers away because its obvious to see your closed minded and don't care to explain things that you don't agree with. Terrible look.
@@BradleyWileyOUTDOOR-MAN Yes, I don't like to use certain alternative materials. Its not because I'm closed minded. Its because I've used them and studied them, and they don't work as well as they are professed to by many sustainable builders. I'm not trying to please everyone with this video. I'm just speaking my mind.
@@thiscobhouse is that a air conditioner in that wall or window???
These cob houses stay cool just like Adobe bricks I thought..
lets pretend this isnt 2 years old. He made the most explicit and effective claim for why concrete is prime. THE SHIFTING OF THE EARTH.
One does not simply ~will~ science away. For your safety and to the thumbs who are arguing about this, may you choose an objectively correct, uniform foundation
As someone who works for Earthship Biotecture: Tires can work great in any climate :)
Also, not liking concrete isn't stupid or ignorant. The energy it takes to make that stuff is awful. Obviously a great building material though.
Thanks for explaining things so well and being so honest. I wish concrete weren't used anymore but you're right that the alternatives are risky. Would you recommend any resources so I study how to build a foundation myself? I want to save money as my budget is limited. Many thanks!
From my point of view and few cob house,mud house i builded, bed rock or big rocks is the most thing possible to replace concrete but it require high skill to put it on exactly and quite expensive, and use high labour to work with, and if you dont do it right, it'll easy to shake and colapse, it's easier when put cement or lime between the rock to make it harder and stand well together, but the problem is most of the world pollution not come from concrete or cement, it comes from agriculture, castle raising, and a part from vehicles and some industry needs to burn things people need usually more like steel, electric or plastic,etc.., But now if we just use cement and concrete for only the foundation, it'll even less more pollution for the construction activities but still make your house SAFETY for yourself but it'll not create much change in decrease world's pollution right now. So from my point of view, i'll just keep use concrete for the benefits of it, while planting more trees ,eats less meat, and use less more things and energy it'll better for environment and create a safety house for you.
I'm glad I came across this video. I keep seeing videos using dry stacked stone and I have no access to (free) stone because my land has literally no rocks anywhere and I'd have no knowledge of how to stack them confidently. I'd rather use concrete block or poured concrete for longevity. THANKS! I would like to build a cob house on top of a full basement which I'm trying to figure out.
I agree! There's little to no good stone in my area, and getting it would be expensive. But knowing that concrete is a good option frees up so much--especially when it comes to putting in a basement, which I really want! It would add so much space to put one in.
How about something middle of the road, like rubble trenches? it is a medieval technique where you dig a trench, install french drain at the bottom(draining on a lower part of land by gravity), fill the trench with potatoes size rocks . Lower footprint since rocks are stacked in a trench up to ground level, then you start a small concrete wall for a crawlspace. No basement. but solid and stable as it can get.
Sure. I like rubble trench foundations, but they still need a stem wall. This will still have to be stone, concrete, etc.
@@thiscobhouse Of course, but a lot less material than a standard footing+full size wall. In fact it could take more or less the same material than a standard footing.
I've wondered for a long time about the stability of the tire wall. The Earthship concept is really cool. But the creators seem to priorities recycling over building a solid building. Like putting the cans in the walls. To me thats a bunch of week points.
Thats what I've always thought. Like what if the glass bottles they use break?
@@BradleyWileyOUTDOOR-MAN if the bottles break they will clean the hole real good and replace the bottle or cob right over it
Yep, I've always been after some heaven on Earth utopia, not a recycling feat
Only because you have yet to grow the balls required to build one, right?
Maybe utopia and recycling necessitate each other? We are not being given tools for self reliance, recycling, utopia. We are being given throwaway products that require specialists. Some of us would rather make long-standing beauty with the least effort, the least impact, even as we make mistakes @@neatcool4770
we are thinking of building a cob house, and our land happens to have quite a bit of stone. Would you think it would be a decent idea to throw some large stones in the bottom of trench that goes below the frost line and pour concrete around it? It just feels better to use as many materials I have on hand if I can without compromising stability.
Curious to find out if you decided to go down that route
Yeah this has always been a question I’ve wondered about too since all the little rocks you collect can just get thrown in and embedded in poured concrete and fill up space, saving money and resources.
THANKS FOR VIDEO! would it be hard for me with no experience to build a concrete foundation? Or if I had to hire someone...Is it expensive to build a concrete foundation? Thankyou
You could do it yourself. Start with something small though.
If I'm going to put in the work and creativity into building my perfect cob home, I'm not going to risk it cracking and crumbling because of shifting. I would still be building a home for much cheaper than conventional style if I invested in a proper foundation. Foolish not to; especially if you want it to be a forever home..
Love the look where the stone meets the cob/plaster wall. Is there a vapor barrier between them? Thanks
I got a lot to learn about Adobe and cob.
I believe I like both..I want to build a 20X30 Cob one room cabin with a small wood burning stove..
What would a proper stone foundation look like? How would you do a hybrid of stone/cement?
Thanks for the video covering foundations
You're welcome! I'm glad you found it helpful.
@@thiscobhouse what is you opinion about cobb houses in cold/wet environments.. or some place that gets snow..
@@thesoliloquist1940 Cold and wet is not a problem for cob if the building is constructed properly. Cob does not have insulation though so you will need a good heat source inside your building if you have cold winters.
I love honesty. Good stuff.
Nuggets of gold being shared here
Hello, Im building in Gambia an been watching your videos to help, and thank you so much these videos are amazing!
Could you use cube wire cages with stone for the foundation and pour concrete to create that one slab effect? save on concrete (although dont want to skips corners) a what are your thoughts on this?
Concrete is one of the main products that is difficult to recycle. It accumulates during demolition. Concrete will always crack and expand. To protect the ground of your home, you can lay a moisture barrier sheet and use gravel and/or broken concrete. You can fill in gaps with cob mixture or concrete and water. If you are in an earthquake prone location, it would also be a good idea to add a steel plate border.
thanks... yes, more info than many vids out there. I live in the Sacred Valley of the Incas, so stone is plentiful and used fairly often... but even here, many people use cement/rebar with adobe for homes, and the precise stonework that you see in Machu Picchu and other ruins, is hard to find.
and almost everyone builds their own houses
Thanks for the great video
Is drainage beneath or bedside footings better?
Do internal walls need footings? Drainage?
Thanks
Peter
Thoughts on rubble trench foundations? We live in Northern MO and planning a cob/bale build.
Have you done any timber frame earth homes before? I’m going to be building a timber frame cabin and I’m hoping to use sawdust as the walls. It’s a fairly small cabin around 14x 16. I’m having a hard time deciding on how to incorporate the foundation for earth walls and timber frame.
I’m thinking I’ll build the walls up on a pony wall and have the timber either on footings, possibly attached to the pony wall. Or should I just build an extra thick pony wall? Any suggestion would be greatly appreciated!
Exactly what I needed!
Glad it was helpful!
I live in Arizona and we have monsoons, I have a concrete foundation for my Strawbale house.
I’m looking to build one in az also, where is your house located?
I love the look of stone, but sounds like concrete is really much more practical... what about poured concrete foundation and a stacked stone façade around the base of the house? Using concrete to adhere the stone to the wall.
I have a huge existing concrete base so does this help me start my small cob garden den I’m here in uk, I have free timber and I’m on clay soil with tons of straw around me so I’m saving on any new materials?
I found this pretty informative, what I don’t completely understand is if you have a “hollow” foundation. As in when you show the foundation components, I can see the earth underneath the flooring layers. So is the foundation made only for where the walls will be build? And then I can see you pour it on surface over the ground, can you detail more in a video exactly where is there a foundation foot and where there is only a thinner layer? Thanks a lot, I don’t know if you will see this comment after 10 months from posting the video.
I'm building a potting shed in the garden out of cob. As it's not really a permanent structure that I will be living in could I build the cob walls on concrete paving slabs or do I still need deeper foundations? The roof and wall posts are wooden.
I live in south carolina. Would the moisture out here effect any possibility of me having a Cobb house in these parts? I ask because it rains alot out here. Just wanted to know. ..and if it is possible to own one, what foundation would you recommend for South Carolina? Love your videos and thanx!!🤍
How do you join the interior flooring concrete (and other materials shown) with the side of the stem wall? Is it enough to pour the concrete or cob on top of the floor insulation or should we bond those materials some how to the foundation at the cross section?
im curious about something, what if you dont need to worry about freezing as i live in an area that does not freeze rather there are tremors occasionally and personally for me its just easier to do a concrete foundations as there little to none broken stone or cement unless your haunting a build site, id rather be building my own lol thanks for the video
Great video, but i have a small Important question.
Is Frost can lift up the gravel or stone when they put it on the frost line ?
Or we need to mix and pour lime or cement with sand after we put the big rocks down there.
But how about the gravel people use in Rubble trench, Frost could lift the gravel up, right ?
So, the only good possible foundation is concrete below the frost line, and the gravel below the concrete to get good water drainage ?
Can you please further explain why not to use tires?
Wow, keep up the good work 🙏❤️
When I see concrete, it always seems to have cracked from thermal expansion/shrinkage, to the point that pavers put those deliberate divisions into the sidewalk to break up the monolithic nature of the material and allow it to expand and shrink without cracking.
So, if you'll pardon the noob question, why is a monolithic concrete foundation better for building than stone if it breaks under temperature changes? (hell, the same could be asked of cob, though i figured it'd be more "flexible" what with being heterogeneous and permeable?)
Where are your workshops available?
www.thiscobhouse.com/cob-workshops/
This year, in Tennessee and Florida.
Could you use concrete cinder blocks instead? Do they need to be mortared together?
Yes. Mortar them together and fill the inside openings with concrete mortar too so its a solid foundation.
Hi, thanks so much for these videos! I was wondering if you had heard of the “carbon-neutral” cement developed by Sublime Systems out of Massachusetts? I don’t know anything about them beyond what i heard on their NPR spot a few months back .. or about cement beyond laywomen use, but it sounded like they have made cement that is chemically and structurally identical to the original stuff but found a way to produce it at scale for similar prices but with way less energy used.
Thank you!
It’s November 2021. Am interested in attending one live seminar this coming summer. Please provide me with a link to go to for signing up.
Great work!!
Could you use a mix of concrete and stone? Also could you substitute concrete for roman style concrete?
Hmmm..
Well, concrete is mostly just a mixture of crushed up stone and cement binder.
You could use lime based concrete for mortar, but I don't think it would hold up as a poured monolithic foundation. Modern concrete is 99% natural material though so its not as bad as people think.
@@thiscobhouse Okay, thank you! Well, I have heard before the modern concrete doesn't hold up as well as roman. I wasn't sure if this is true but personally I put a lot of trust in ancient methods of building, but that is just my opinion.
I don't get the drain pipes? From where to they drain to where? If you just surround the ditch with a drain, how does water even get inside it?
I'm hoping to build a cob chicken coop, can you recommend a foundation suitable for that type of build?
Stone, brick, cinder block, or concrete are some good options for a chicken coop.
Could you do concrete foundation with concrete root cellar inside?? I have lots of plans just want to keep sustainability.
Yes, assuming your root cellar is under the foundation you would essentially be building a basement to use as a root cellar so research that.
Do you recommend hemp crete for foundation?
Not for foundation. Only for walls.
I made the mistake of watching this with my wife and she won’t stop making marriage foundation jokes lol
Just have to know. Do you have a rubble trench around your entire perimeter? :)
if a person is pretty confident in their ability to lay stone and has access to stone on their property would you still suggest concrete?
Not necessarily. Do stone if you're confident doing it.
Can you put up more videos being more detailed aboht foundation. I see alot of things in video that id like info on. For example .. That is the pink part of foundation and what is its purpose..
Okay. Yes, that pink part is insulation board. Only needed if you are in a cold climate, really.
Good information. Clearly you know your stuff but thank God for 2X speed.
Love the hobbit door ❤
I do enjoy the look of the old stone foundations. I wonder if trekking over to the UK to learn from master masons that are still around; they could teach on the stone foundation construction of the their 500+ year old cob buildings... would be lovely if feasible. An art form such as that should not be lost.
Your concrete foundations do look nice though!
Thanks!
I got the chance to learn from a Master stone mason in Oregon back in 2013. You might be able to find one where you are.
I love the look of stone foundations too!! They're jsut really..majestic and sublime, you know??
Yeah, if I build cob up in the mountains, stone foundation is the only way.
Can you build a cob house on piers or would that be too heavy?
What about condensation points and other moisture issues?? A cold material like concrete or steel rebar could cause mold if it's in direct contact with natural building materials, right?? I live in Massachusetts.
Yes, interesting question. I think the new code calls for putting a vapor barrier on top of a concrete foundation/under the cob walls.
@@thiscobhouse I recently watched a video about this. A woman explained that there is moisture in liquid form and moisture in gas form. Her argument is that liguid moisture is bad. You want to keep it out, or else you get mold and rot and expensive replacements. While moisture in gas form is good. You want it to have full access to your entire building. That way the humidity and air quality inside the building is regulated by the building itself. I thought it fascinating.
@@thiscobhouse And your video also makes me ask myself more questions about concrete too. Are there ways to reduce CO2 emmisions in it's production?? Reducing the amount used with rubble foundation sounds a good idea. But also, could there be alternatives in monolithic form?? As you said, concrete is mostly natural products. If it is so similar to natural products, could there be a way those concrete-like products with a lower footprint be used?? I'm thinking something like rammed earth. Speaking of tires, I've been told in England they use tire bales as foundations for highways and other road projects. It's drains the foundation as well. So much to unpack here!!!
Would you recommend concrete if I wanted to make a pallet cob chicken cob house??
Yes, I think a concrete/masonry foundation would be great for that. You don't have to for a chicken house though. It just depends how nice/long lasting you want it to be.
Thank you.
While you are constructing the foundation and the infrastructure, could one start making cob bricks or blocks lg/sm, so when it comes time to build walls most of the mixing and drying is already done? Just put the blocks in place and fill in the gaps with fresh cob. I know it's more complicated than that, would that save time in the end to have most of the cob already made and ready to put in place? Will that weaken the cob wall?
Glad to see some common sense about concrete. Seems like I hear how bad it is, and don't use it. To me it is the best material for foundations.
THANK YOU FOR INFORMATION
very good explanation
Great video Alex! Keep them coming.
Thank you!
More coming very soon.
What do you make of straw bale construction? It seems risky to me here in the UK with the damp. You see these middle class types move out from the city to the wilds and build them quite unawares of the fact rats can get into anything and if hay gets wet it can spontaneously combust. I suppose I just answered my own question.
We should have the COB Institute request random particle generation and simulation in the Physics Software like COMSOL and Altair. I'd like to see it for Tribo-Electric Charge (Static Electric charge) anyway it's not there yet. But probably not far off.
They could then be simulated Seismically for Rammed Earth, COB, . . . I'd like to know how the walls perform under Transverse and Longitudinal Waves.
The simulation of mud might not be far off of space dust and Clustering / Clumping Theory - Nebular Hypothesis. Not sure doubt anyone has done it yet.
Oh one of the Mudgirls Structures stopped a tree. lol. That's pretty impressive actually.
Concrete is not the best foundation or the only foundation. Its just the expensive option and cheap option for manufacturers. Its easy and cheap for them but bad for the environment and read up and its water wicking.
I agree monolithic it must be, and concrete has its place there.
In actuality, there are two camps, monolithic and floating foundations. Look at some of the tallest skyscrapers. While they are indeed concrete, the buildings are not directly tied to them in order to give the building a buffer from seismic movements. And in the same way on a smaller scale, we have rubble trench foundations.
I couldn't agree more, watching all these build videos the number one mistake I see are the stem-walls and foundations. I plan on starting a build next year and am going 100% concrete period the end. The last thing I will chance is having foundation problems or failure after spending all the time, money and effort it takes to build one. It just doesn't make sense.
I've been studying natural building and have a question. Is there condensation between the concrete foundation and cob walls?
Water 'can' wick up through a concrete foundation (or any foundation for that matter), but is very unlikely to unless you have some major drainage issues around your house, for example. The cob code does specify to put a water barrier on top of the concrete stem wall foundation to prevent water from wicking up into the cob walls. In my opinion, this is very unlikely to happen though. Its more of a fail safe measure. Even if some moisture gets into the walls, it will quickly dissipate back out before it can do any damage.
Love you're info, solidas a 🪨 foundation or concrete, 😆 🤣 😂
Thanks for the video, it's really informative.
What's your take on fly ash instead of store bought cement?
My understanding is that it is frequently used to replace up to 50% of the cement. I'd hesitate to go beyond that without doing more research. Don't over-water the concrete. Fly ash can make a stiffer mix so you may want to add a plasticizer rather than extra water. If you're getting a mix from a local ready-mix concrete supplier they'd certainly know what local code officials accept. If you're making it yourself the IRC 2021 code mostly allows for a minimum strength mix of 2500 psi (Table R402.2). Normally there's no need for more strength than that. So if you want to save on cement, don't make the mix stronger than necessary.
On the other hand it's critical to keep in mind local conditions. Slopes, compressive soil, fill, expansive soil and a deep frost line are all things that should be considered.
*It is SO EASY to just tell people to "just spend the money"......"just do it"......"don't skimp".....*
What about aircrete? Could that be used for a foundation? I would like to build some cob structures on my property possible a home as well. I would really love to have an earth integrated home or completely underground. Is it possible to use cob for those structures? Also what about rain? What do I have to do in design to accommodate for rains? Or for underground if it's possible? Thank you for your time and assistance and all the videos. Truly appreciated!
Hi Leigh Ann, the aircrete mixes I've seen give a maximum strength of a little under 1000 psi. The building code for houses, IRC 2021, requires at least 2500 psi in most cases. So if you're going to go by code and get a permit I doubt aircrete is a solution.
Aircrete is not structural at all.
Surprised you didn’t cover moisture and concrete. My concern is how much water may wick up through the concrete to cause moisture damage to the interior of straw bale walls, especially in cold damp climates. Not to mention the cracking of foundation walls due to the freeze thaw action in such climates.
Rising damp happens mostly with basement foundations. When foundations are sitting in a pool of water. Foundations could have this issue, especially in northern climates though since the foundations should be dug below frost line to prevent frost heave. Yes, these are concerns, but I think they pertain to all sorts of foundations.
Absolutely. Cement is hydrophilic, it soaks up water. This is why you have to have a membrane and very good flashing between it and any organic material. As for freeze thaw, insulation below and on the sides help to slow the thermal transfer to abate cracking. That said, I don't believe this chap has done enough homework to be an authority on the subject. I'd look elsewhere. And, I'd suggest looking into rubble trench foundations, that is if you're local building code will permit them.
Nice mixer! Cool spot!
M for lime/sand concrete + lime-sand-soil blocks combi.
I thought the any foundation was key to any structure stability and longevity , and you just verified that as pertains to cob. thanks.
People should know that concrete will harden over time and peak at 50 years then start to decay and disintegrate. If you ad fly ash to the concrete mix, it will last thousands of years. Just FYI.
Are you talking about fly ash as used in geopolymers? I would totally use geopolymer concrete if it was widely available.
I do agree that concrete can disintegrate over time, and sometimes the rebar can expand causing spalling. But let's also remember that stone also will disintegrate over time. Especially soft stones.
Thanks for your input! Good information to know.
@@thiscobhouse I guess it might be easier said than done to use fly ash but easy in my area as the power companies use coal at the power plants and the result from burning coal is fly ash. The reason there are roman structures around today is they used something similar and I think it was vulcanic pumic or something similar to fly ash. I totally agree with you about using concrete and definately using rebar. I would never build anything only using stone as a foundation.
If you have time could you look at my initial design real quick. I plan a center steel piling. FB
what do you think about urbanite?
Its okay, but basically falls ito the category of using stone as far as the pros and cons.
Though I appreciate you addressing stuff like foundations and the effort it takes I found this video to be very one sided. Concrete has many wonderful things about it but it also has weaknesses. The fact it accounts for 8 to 10% of all CO2 emissions as well as that it is hydrophilic and porous. Concrete draws water all the way through its system. One of it's greatest strengths is that it's monolithic but its also a great weakness because this means it is very difficult to repair if there are any cracks in it. Concrete foundations built up to code often need extensive repairs after 30 to 40 years which costs tens of thousands of dollars. Concrete is strong being around 4000psi but its super weak in tension(considered negligible in design at 400psi) meaning there has to be steel rebar reinforcement in the tension areas. Unless properly treated a lot of this rebar overtime will get wet from the porous nature of concrete causing rust, expansion and then cracking which creates problems. I have taken extensive classes on concrete and just as they sing the virtues of concrete in traditional education there are definitely drawbacks to it. I think a better explanation as to why these other foundation systems are bad is needed. I found that there was almost no evidence provided in this video to support the claims made and know for a fact that there are many examples of foundation types other than concrete that have a good track record. There are many examples throughout the world of stone foundations much much older than modern concrete. As for stuff like earthbags, time will tell, but for sure there is evidence that they do not start crumbling by the time one finishes the tops of their walls. Are they good foundation techniques? I don't know and there hasn't been enough time or testing to show if they are or not. Please correct me if you think I am wrong about any of this. I love learning and just wanted to point out a couple things I felt people should know.
I think we would all agree that concrete can be a wonderful material in construction. Like any material, it can be misapplied or be of substandard quality.
Alternative building methods which attempt to mimic or reproduce ancient methods are often void of concrete as a material.
Can a viable foundation be constructed without concrete? Absolutely. Look at the ancient buildings still standing on nothing but stone.
In the interest of keeping costs manageable many seek a building alternative more conducive to DIY.
To call people "stupid" or "ignorant" because they hold a different opinion is somewhat caustic, condescending and adds nothing to the conversation.
Simply, state your case and give the data (empirical or anecdotal) to show how you arrived at your conclusions. Others will consider it, or not.
Just because a truck deposited tons of concrete at your building site, does not guarantee the foundation, slab or anything else will be issue free.
Consider, how many times you have seen concrete being placed and then finished, only to see the crew walk away without addressing the curing process? Answer, almost always.
Why? Because despite the common knowledge that "concrete cures best that cures slow", the contractors (or installers) make no time to address this fundamental and important key element.
Concrete and cob seem like a old and new design all in one. Well, actually, concrete is a pretty old tech so win win.
Coding/legality aside, is stone structurally inferior to concrete? I live in the granite state and people will literally give stone away for free.
Its only inferior if constructed poorly. A well built stone foundation or wall is great!
well said.....
I don't know much about cob building specifically but I've worked lots of blue collar jobs in my life. The fact that people would call you an idiot for recommending that you don't use bags or tires or individual stones for a foundation is absurd lol I can understand wanting to stay with tradition, but why stick with tradition if you can't do it properly and have easier cheaper more effective modern alternatives? I imagine an earthquake wouldn't be too nice to a house made of cob that's essentially one single rigid piece that's sitting on a broken up stone foundation lol
I hear ya! I don’t like concrete, but you can’t beat what it provides. Now there’s ways to work with concrete that most don’t take into account, like a slab with walls to have a floating wooden floor. However; haters gonna hate. You know your onto something with the amount of resilience you get
This is great. It is a pity that there are no such people in Russia
I live in a town where there are buildings with stone foundations that are several hundred years old... cement will never last that long.
I didn't say that stone foundations won't last hundreds of years. I think you're missing the more subtle message of the video.
@@thiscobhouse
This is a RUclips comment it is not meant to be exhaustive, sir. I appreciate your channel, and I am not opposed to cement, but I am just wondering out loud if once one factors in the relative longevity of a well made stone foundation it wouldnt up end up being far cheaper than cement.
@@felixguerrero6062 it's not subtle
Gabion foundations is the answer! No concrete needed or high skill level like dry stacking.
EXUSE ME?
Do you know how much carbon emissions go into making concrete?!
Yes.
Thank you for this video. Could i use earth bricks placed below the earth for the wall foundation in the same manner they are placed above the earth as my wall? It would be an 18in wide foundation, and using mortar to bind the bricks in the foundation to be more monolithic. I look forward to your reply.
No CEBs will not work as a foundation. Look into rubble trench foundations.
The windows are not up to code, Florida hurricane!
Do Florida windows have to be attached extra secure? I don't know this part.
Why not just use cob?