Bridging of the damp proof course tips, and the questions you must ask a damp surveyor
HTML-код
- Опубликовано: 21 июл 2024
- Bridging of the damp proof course, or bridging of the dpc, is such a common cause of rising damp to internal walls, and also external walls. BS 6576, and BRE DIGEST 245 is the standards that all damp surveyors should be following.
As per the video you need to ask your damp surveyor some vital questions.
If you don’t ask these questions you might fall into the trap, and perhaps your root cause of rising damp will not be diagnosed correctly, that could result in expensive treatment and repairs.
By getting the correct survey initially, it will add value long term.
1. First of all you need to make sure your damp surveyor is suitably experienced, and qualified.
2. You must ask for an invasive / intrusive / destructive survey if it’s anything to do with damp at the base of the wall, and possibly bridging of the dpc, like rising damp. Non invasive surveys will simply not be good enough., but will be pushed by damp surveyors as these are cheap and quick.
3. An averagely competent surveyor will follow the guidance in BS 6576, as per what I have spoke about in the video.
4. They will also need to follow the methodology in BRE DIGEST 245. This is basically the only quantitative methodology to confirm rising damp, by using a carbide meter / speedy meter or better still gravimetric analysis.
5. Make sure all of the below are eliminated as a potential cause by your damp surveyor, as per guidance in BS 6576.
1. Condensation
2. Lateral penetration associated with ground and floor level
3. Leaks from roofs gutters, and downpipes
4. Faulty drains
5. Internal plumbing leaks
6. Water penetration through external walls
7. Water penetration around windows and doors
8. Mortar droppings in the cavity
9. History of flooding
I do find that if a physical damp proof course is present and there is damp on internal walls, there
is a high possibility there could be drain issues, or a possible leak.
BRE DIGEST 245.
Click the link to my website to give you a better understanding about carbide meters / speedy meters
www.completepreservation.co.u...
Click the link to my website to get a better understanding of the carbide meter / speedy meter
www.completepreservation.co.u...
The latest damp methodology by RICS, SPAB, HISTORIC ENGLAND, HISTORIC SCOTLAND, PCA, CADW
www.completepreservation.co.u...
0:00 Introduction
1:10 DPC bridged by debris within cavity
1:45 DPC bridged by mortar
2:08 DPC bridged by external render
2:32 DPC bridged by high ground levels
3:01 DPC bridged by the solid floor
3:26 DPC bridged by plaster
3:47 BS 6576 2005 BRITISH STANDARD
5:42 What needs to be eliminated ?
If you need any advice regarding damp issues drop them in the comments :)
Follow us on our social channels where you can get free tips on damp and building defect issues, and you can engage and get your questions answered.
TicTok
TikTokwww.tiktok.com › @complet...Complete Preservation (@complete_preservation)
RUclips
/ @completepreservation
Instagram
complete_preser...
LinkedIn
/ ross-charters-85883b52
Facebook
Facebookwww.facebook.com › compl...Complete Preservation | Trowbridge
#bridgeddampproof course#bridgeddpc #risingdamp #damptreatment #dampsurvey #diydamp #Wiltshire #renovation #damptreatmentforwalls
Excellent video Ross.
Perfect cpd for us building surveyors.
I hope you keep producing all these videos, as I certainly find them most helpful
Thanks Paul. I’ll be posting some case studies of terrible diagnosis next week 👍 and I’ve got another one going up tonight about the damp survey scam on non invasive damp surveys👍
This has got to be one of the most instructive and thorough guides to damp investigation out there. A must view for anyone seriously interested in getting to the root causes rather then getting carried away with the symptoms. There is no doubt that Ross is a true professional with a real interest in his work.
Thanks Alan I’m blushing now😊
I’ve had so many kind emails from this video… hopefully it helps a few people out before spending a chunk of money 👍
That video etc was exactly what is needed - Education, based on knowledge, for the interested.
Exactly bud most want a bit of eduction to ensure they don’t get ripped off 👍
Excellent advice, thanks.just had a survey and they immediately recommended chemical dpc and tanking plaster job..no mention of your points along with the potential of externally painted bricks and internal plaster and paint adding to the problem.
I’m actually looking forward to investigating now😂
Thanks Chris 👍 Im sure you will enjoy it 😜
This was really helpful. Explains things clearly. Thank you!
Glad it’s so helped james, hopefully u won’t get scammed now 👍
Hey Ross, any detailing for when a DPC can be covered with render? I see this much, especially to 1900's property.
The cavity issue is more to do with it being lateral damp. Its moisture running down the cavity and being driven towards the inner blockwork face by the fact the concrete cavity fill isn't tilted down and out away from the inner blockwork. Also the solid wall example is always caused by the solid concrete floor itself. There's no bridge of the DPC as in the netherlands a wetter country they don't use DPCs. Because concrete is actually impervious to water so what happens is moisture build up under the concrete floor. The solid wall damp is then caused by the unbreathable solid concrete floor displacing moisture laterally (sideways) into the brickwork wall presenting itself as salts from the pink unbreathable plaster, which is what attracts the moisture. Fit a suspended concrete or timber floor with underfloor vents, or limecrete floor with no DPC and it will be completely solved. Also replaster with lime. This works every time. Especially on old houses. DPC abridgement is not a thing. Its actually to do with lack of breathable materials, ventilation and poor detailing.
Dpc bridging is a thing bud, those drawings are from BRE digest 245 what an averagely competent surveyor should recommend in regards to eliminating damp issues👍 You should buy a copy, it’s only about £15. I carry out gravimetrics, which is quantitative moisture analysis, so I know my diagnosis is 100% accurate👍 what capillary moisture contents are you getting with concrete floors and after replacing them 👍only asking as I’ve seen many buildings with solid concrete floors and no rising damp 👍
Thanks.
You're welcome👍
Brilliant video, I really appreciate the drawings, I have a small strip of damp on outside edge of a tiled floor on a concrete base,it occurs on chilly damp,wet days but still disconcerting it's approx 10 mm below the damp course on a single brick exterior wall in a porch which is open plan to the rest of the house.At present doing the foil test to see if it's coming from below or whether it's condensation hitting a cold spot.Any advice would be appreciated.
Thanks David… send me some pics 👍
@@completepreservation Hi Ross,just spent last 3 hours trying to get you some photos and for the life of me can't. But Thankyou for offering your time to take a look at my problem. As I have now subscribed to your channel I will keep watching and learning!🙂👍Thanks again.
Hi Ross, great videos for someone like me who is currently having to look into these issues and deal with damp surveyors. If the issue is DPC bridged by solid concrete floor what is the solution for this? Alternatively, if it's due to DPC bridged by plaster, what's the solution for that too? Thanks
Thanks bud 👍 you can cut back the concrete to remove the bridging issue, and the same with plaster. Have a look at this one bud ruclips.net/video/OrzNcVFqvUk/видео.html
Hi Ross, Brilliant video.
If after all the diagnosis you explain we're convinced we have rising damp. Please explain why on all properties we see with an injected damp proof course on a solid wall 1930's house it is done two courses above the existing blue brick course and not on the motor course immediately above the blue brick course. I have an single internal wall which separates the lounge from the stairs and this has started pushing salt out on the plaster and lifting the wall paper on the lounge side and showing salt deposits on the non plastered side. There used to be an outhouse under the stairs but I bricked it up and to access fron a new door from the kitchen. I put a concrete floor in there with a membrane that went all up the sides against the internal wall and knifed off so I don't think it was bridged by that. Is it possible the a 1930's house's original two row bluebrick course has lost its damp proofing qualities and that a new one is required perhaps by drilling and plugging with the sticks you can buy now. If we dry washing in the house could this be the problem even though it's low on the Wallsend? Surely condensation would be higher on the walls or wiped off windows? An early reply would be most appreciated mate. Regards Tony not trade just DIYer.
Thanks for the kind comment Tony 👍 unfortunately the blue bricks still allow moisture to pass through the mortar beds, so you can still get rising damp with them bud. See in this post where they actually left the perps open to prevent this occurring 👍www.linkedin.com/posts/ross-charters-85883b52_from-a-100-year-old-book-in-regards-to-damp-activity-6829404555223035904-g1y7
Thanks Ross, invaluable. May I ask if a good idea would be to remove a few floorboards as is a suspended floor and do a new damp proof course using the new style sticks. The wall I'm talking about is a single wall (I think I said) but I'll be doing the double wall to as they are giving out the same symptoms. Also why do I see injection damp proof courses are usually done a few rows above the blue bricks? Doesn't it make sense to treat the mortar directly above the blue bricks? and can you see any reason for the insulation I've put between the joints of the suspended floor causing the damp up the wall. It doesn't touch the walls but I have felt condensation on its bottom surface ( ie like drips but not actually dripping) the vents are still open to give aeration. Again many thanks👍
Hi Ross
Your video are brilliant mate.
Would you be able to give us some advice please.
I’ve recently purchased a property for myself and family and in the process of renovating it.
The ground floor has a mastic asphalt floor about 20mm thick, but it falls short of all internal walls about 40mm after removing all skirting boards plaster was down to ground level. I’ve created a gap and tide marks on wall have started to dry out.
Will I have to remove affected plaster or leave to dry out?
I can also see the dpc which is the same height as the concrete slab underneath the mastic asphalt floor. Would I be able to infill this gap around the ground floor with a waterproof cement mix??
Any advice would be appreciated.
Kind regards Michael
Thanks bud, really need to see if hygroscopic salts are present in the plaster 👍
Excellent description. I've recently discovered that our issues may be cause by a bridged slate dpc externally pointed with render consistency mortar. Is it best to grind back the render and leave the slate exposed or does it require pointing up with lime mortar? Thanks
Thanks for the kind comment Jon. Watch this video bud as I talk about it and show how it’s done 👍hope it helps 👍 ruclips.net/video/UkX87ATwHGE/видео.html
I have a concrete undercover verandah the full length of our house. The concrete is level with the damp course proofing. I would like to tile the verandah with 12mm travertine tiles. What could I do to ensure the tiles don't bridge the DPC. The verandah ensures there is no rain splashback to the walls. Thank you
Hi Karlene, really you should get advice from your contractor doing the works. It’s difficult to give advice without being able to carry out a survey 👍
Ross a property I'm buying has render right to the floor on the outside. I have seen in your vids that you removed some of this to the correct height. Can this be done on any property or will it take the face of the brick off when removed. What's the best way to to remove without damaging the render above or the bricks? Thanks
Ello bud. It really depends how well its bonded to be fair. Probably best to remove it with a hand chisel. You can set a grinder to say 10mm, and cut some small squares.... that sometimes helps breaking it off in small chunks :) Just need some luck really!
This is great information. I can't make out what you said at 2:25, about repairing a damp problem caused by the external render. What is the solution to that?
Thanks 👍 you can cut bridging render, and form a bell mouth, bell drip, also known as a bell cast. I’m just finishing a job tomorrow, and I will post on youtube next week 👍
@@completepreservation Thank you! Makes sense now. Look forward to the new post
Excellent. Quick question: if you cut out a concrete path and make a channel, but then fill that channel with shingle up to the dpc, is that still bridging?
If it’s up to it, it’s not bridging. But it isn’t good practice bud , as it will still allow splash over 👍
Thanks Ross, invaluable. Further to my question yesterday bud, May I ask if a good idea would be to remove a few floorboards as is a suspended floor and do a new damp proof course using the new style sticks. The wall I'm talking about is a single wall (I think I said) but I'll be doing the double wall to as they are giving out the same symptoms. Also why do I see injection damp proof courses are usually done a few rows above the blue bricks? Doesn't it make sense to treat the mortar directly above the blue bricks? and can you see any reason for the insulation I've put between the joints of the suspended floor causing the damp up the wall. It doesn't touch the walls but I have felt condensation on its bottom surface ( ie like drips but not actually dripping) the vents are still open to give aeration. Again many thanks👍
No probs… personally I would get all drains checked, mains water, and all plumbing initially 👍
@@completepreservation they're all fine. Do you mind addressing the questions I asked regarding what mortar course to treat. And if the under floor insulation can cause risng damp.Cheers
You really need to pay for a professional to survey the building, and find the root cause. Insulation cant cause rising damp, but it isn't unusual for it to suffer from condensation issues. normally find drain defects, causing excess moisture.....
a question for you and i would like you to answer on here if the outside ground level is higher than the internal level would you use tanking ? to combat the below ground level problem? another question are the brick suitable for either use the old method of water based chemical injection or the new method of damp proof cream? also if you use the new damp proof cream which is recommended to go in to the mortar joint and and your mortar joint is over 4 inches above floor level how do you fit 4 inch skirting if the customer insists if there is no render to fix to without causing a damp bridge i have been in this industry for over 30 years and always use tanking and i have been using the same landlords for same period and not once have they say we got a damp problem there are many problems that cause damp from rising to penetrating damp from bad outside render bridging duh we live in Britain and we have rain seal your property up make it watertight open your windows in winter to allow the air from your unbearable hot house to be free and you dont waist my time to say hi i got damp in my property and i test the walls and they dry but covered in black spot mould google black spot mould for gods sake we all got different lifestyle habits dont breath hard when having sex in your bedroom open your windows in winter to allow warm air which causes condensation to condense on your cold walls to escape
Hi Andy, its an interesting question! Normally I would always try and lower the ground level, and if this isn't possible I would carry out a repair in line with BS 8102.This link might be of use bud. ruclips.net/video/m85jAjGcemw/видео.html
Great video, but I had one other question about bridging the damp-proof course. I want to paint the internal wall of our garage, which is attached to the house. Do I have to worry about paint bridging the damp-proof course, or is that not a problem?
Thanks : ) If the paint is going beneath the dpc and its a more modern non breathable type it will most probably come away and blister
Hi, What's the remedy for a DPC that has been breached by a concrete floor? Thanks
Can you lower the ground levels 👍
Hi, Are the cheaper Amazon moisture meters good enough for moisture profiling? Thanks
Ideally something like a Protimeter surveymaster, but if that’s all you have use that 👍
How do you solve rising damp due plaster bridging of the DPC on an internal wall ?
Hi Dan, you can remove the bridging plaster. Is the plaster damaged?
Replaster and have the plaster stop (maybe 25mm) short of the floor to create a channel
How can one tell the Damp surveyour is qualified.
Thamks
You really need to ensure they can find the root cause. So the questions listed should help you choose the correct surveyor 👍
My dpc is two blue bricks. How low should the garden be so I don’t cause problems.
Ideallly 150 below dpc 👍
@@completepreservation thank you. I’m glad I found you and learnt what dpc is.
You’re welcome 👍
Had a surveyor out who did a visual survey of a damp bay window, straight up rising damp and DPC diagnosed, should I get a second opinion? He didn’t even look at the outside of the window for crying out loud and I had to pay £60 for this “service”!!
Hi john, a bay is notorious for condensation damp. Has it got a physical dpc as per the video you watched?
@@completepreservation it is rendered on the outside so I can’t see any dpc. It looks like a different construction to the walls either side of the bay, where I can see the dpc.
Need to hunt down the dpc bud…. 👍
@@completepreservation how do I find it chip off the render? Or dig down below the ground a bit?
Im needing advice
Social housing ground floor flat
Defects in & out gave me no choice but to involve solicitor
0.5” damp course above ground level!
Brick weave on top patio laid against building
Down pipe under sized as stated by Independent Survey Report
Blocked drains due to moss from roof blocking down pipe/drains up
Bubbling drains when it rains water sit not only below damp course but above it
I feel underneath flat it must be wet through as bricks next to drain have cement damage between bricks badly
My new kitchen was put in last week
The damp is unbelievable on the internal wall
My solicitor has been changed so must do a letter but please help me from a professionals point of view
What is happening to flat I.e footing deteriorating away
U can imagine defects internal
A barrister is going to give verdict court or not it’s done in percentage
Please please try and help me
Adele
Im literally besides myself I truly am
Hi sorry to hear this
drop me an email enquiries@completepreservation.co .uk
@@completepreservation Thank you so much Ross! When I get a minute I will definitely email you
Adele x
No probs 👍
But I don't have any DPC in my house...? What now!
Be best to get a decent damp surveyor if you need help bud. This is just general tips, but the questions are there for you to ask a damp surveyor prior to paying for a survey 👍
@@completepreservation They just try and push damp rods etc!?
Ask the questions in this video prior is my best advice 👍
Great vid/s?
Thanks 👍
Rising damp simply doesn’t exist …..it’s simply condensation
The fact your other example had cement render on a solid wall is the entire reason for condensation issues…..remove the render
Hi Dale, have you actually carried out a survey following the guidance in BRE DIGEST 245. which is the quantitative methodology for the diagnosis of rising damp? Have you actually even had a read of the joint statement by RICS, Historic England, Spab. Cade, PCA, ihbc and others? Why does it even mention gravimetric analysis if it didn’t exist?
@@completepreservation what are you using to diagnose “rising damp “
I follow the joint statement as above, as to be expected by an averagely competent surveyor. You still haven’t answered my question though… I take it you don’t use BRE DIGEST 245
@@completepreservation the point I’m making is ……BRE 245 is a way of diagnosing rising damp……I’m stating that rising damp has been shown to not exist ……it’s simply condensation! Damp does rise …..it’s simply condensation which just so happens to be at the bottom half of the wall as this is the coldest!
So if there is a mains water has a leak under the house damp will not show on a wall? If there is a defective drain damp will not show on a wall? Where do the hygroscopic ground salts come from then? An averagely competent surveyor understands the basics in these questions, and whilst rising damp diagnosis might be poor, it certainly does exist bud. Go and do some sampling following are digest 245 and come back to me.... make sure you data log the internal dividing wall that's warmer to, so you can see for yourself :)