Sweating and Wet Parapet Wall, Cavity Wall Insulation
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- Опубліковано 30 вер 2024
- Doing roof inspections, I often find that the parapet wall is the problem, not the roof itself. Cavity wall coping stones leaking into the cavity and making the cavity wall insulation wet often results in thermal bridging. In turn, this thermal bridging inside the cavity then makes the wall cold and attracts moisture, making it look like there could be a roof leak. Normally there are three or four problems all happening at the same time:
Incorrect size of coping stones
No Damp Proof Course (DPC) or the incorrect DPC.
Badly-installed cavity wall insulation and thermal bridging of the cavity normally because cement "Snots" from the brickwork have bridged the cavity.
Even when I'm doing a roof inspection of a new roof I tend to find one or two of the above problems with the coping stones or the parapet walls. The reasoning behind all of this seems to be because of the following:
No training of our construction workers.
No support for our construction workers.
Bad oversight of new construction.
Incorrect detailing/drawing/information given at the construction phase.
To make things worse, try getting hold of the correct materials.
If we take suppliers of coping stones, the small builder's merchants only stock certain size coping stones, normally sized for solid walls and, as we don't build many solid walls any more, that's a bit of a problem. So we have to order the correct size coping stones and that takes time.
Coping stones have to be laid onto the correct DPC (damp proof course) and getting the correct DPC (damp proof course) is also a problem. Most builder's merchants only stock a plastic DPC (damp proof course) that is not meant to go under coping stones. Thus all of the above leads us to where we are i.e. badly constructed new extensions, loft conversions and poor housing stock.
This is one of the few channels putting out information you won’t find anywhere else
Thanks
Perfectly explained as usual. Thanks Steve.
Glad you enjoyed it
Right on! I like to hear people saying things as they are. Poor design, no supervision, poor workmanship = crap results. It is a blight specifically in London, and it is a simple matter of people not being competent or simply not caring about the results. I hope new comers the the industry will take note,put some effort and pride in their work and eventually or hopefully, change the opinion of terrible workmanship we have in this country.
Unfortunately the rest of the country is now suffering from the same problem yes London was the main culprit but not any more
I’ve learned so much from this man/channel
Thanks Steve
Thanks
@@SteveRoofer I must make a donation to you’re charity in fact. Help for heroes?
@@raybans8712 My link not working at the moment but please do as it all helps our solders
Brilliant video Steve!These situations are an absolute nightmare!Seems that a normal property survey isn't much cop when buying a property.Seems that its difficult to know what you've got until you peel the thing apart!All the best for 2022.👍
Exactly right however it's now keeping me in work . Im spending more time doing roof surveys and reports for new house buyers than I am doing roofs now.
PLO
A non intrusive property survey is a complete waste of money, the biggest waste of £800 spent on my last property
Good vid. A couple of other things to note as well. Foil backed insulation should have a ventilated cavity to allow an air flow to remove moisture forming, it should not be used as full fill unless to the manufacturers installation guidance, and during construction a stepped dpc should be installed with weep holes to capture any moisture in the cavity and to prevent it going down to the habitable areas below. Perp end weep vents would do as well which would allow extra air flow into the cavity.
If only we knew the make of the insulation I could look it up to see if it was mad for full filled cavities. Love your choice of chill music
Great demonstration steve but it never sits right with me not having a mechanical fixing?. Just like when you build a chimney on a lead tray there not much adhesion to the damp coarse so it's live. So many times have put a ladder against a chimney and it starts rocking
I know that the regs have changed so that coping stones on pitch have to be fixed down but will have to look up if the change is also for the vertical. Whatever I cannot see how anyone is going to do this correctly with the fiddly dowel fixing that have been preposed
@@SteveRoofer I would screw some 100mm screws into the brickwork leaving 50mm pertruding on every other perp joint and a dab of silicone arround the base where it penatrates the dpm to reinforce it
Totally agree with Peter you must have mechanical fix, especially important at height. We use or have used in the past s/s dowels, if correctly installed will never cause any problems with moisture ingress. On chimney work, rebuilds we also use s/s cramps for lateral stability. Unfortunately, as pointed out by many in the comments, there’s a lot of ignorance & or poor workmanship out there. My intention isn’t to plug our business but since I’m here, we are based in central Scotland Cameron Building Services and offer an informed & quality service.
Steve. Thank you very much for such an informative video on materials, correct application and faults from previous builders. You also helped us very much to resolve somebody else failures on the parapet and DPC application.
The long and short of it is, the labour completing these jobs A) don’t care as long as they get their £12ph, B) haven’t got the physical brain cells to work out what is correct and C) probably don’t even know what BS stands for 😂
Thats part of the problem
Brilliant video ❤❤it 😊😊
Thank you so much 😀
Old military adage: remember lads your kit was built by the lowest bidder.
I used to price/quote for 2 or 3 jobs per week in the 90-00s. Without fail at least 1 out of 3 potential clients would say something like "company x has quoted £y,000". My reply would generally be along the lines of "What would you think if I said we could do the work for half the price of company x?" The response would usually be alongvthe lines of, " you must be cutting corners". "That's what you want" I'd reply as I ended our conversation.
Always, always purchase based on quality. If you haven't seen examples of work, or had recommendations from friends, family or previously satisfied customers, then you'd be better off spending the money you're about to invest on the Lotto or Premuim Bonds. Buy cheap pay twice. Unfortunately if this is London it wouldn't have been cheap, just cheapest perhaps. Keep up the good work Steve.
The good old days
Well put together and accurate video. I’m a chartered building surveyor and this problem is more common than it being done correct. I’ve done an expert report in a whole new build estate where it was so poor the builder spent years trying to put it right, but didn’t have a clue. Only comment I would make is mortar to the joints on copings is not ideal in any situation and although yours looks like a great job, I specify a Sika/Everbuild Puraflex 25. Back point it, then put a good joint with this as it provides a water resistant seal and allows for the movement. Portland cement based mortars don’t generally move and as such they crack. 👍🏼
Like you, I see hole estates with the same problem. You are totally correct about the cracking and that a flexible sealant would be better however more costly and perhaps not necessary if build correctly in the first place, if it's built correctly in the first place you have built-in redundancy. IE if the pointing fails and cracks, lets in water the totally sealed and overhang DPC will not let the water penetrate into the cavity wall
Bang on. If there was a cavity try and the necessary design carried out correctly then yes you are correct, however always best to prevent this being relied on if possible. Puraflex is £12-15 a tube and a couple of tubes would probably do it and they do it in various colours like buff to go with stonework. £30 well spent 👍🏼. Keep up there good work.
I was ⚠️ why not use lime motar instead of portland cement for the copeing stones. 😳
Totally agree with Thomas -using lime. 4 Sharp sand , 1 cement , 1 hydrated lime. Bedding and pointing at the same time. Code 4 lead, well scratched both sides , as dpc.
@@andyphillips7435 Indeed Sir, I'll bet you see a lot of shoddy work out there.
Very nice explanations and informative. I'm not even a builder but at least now I have some idea of what is required to keep the walls from being wet.
OK thanks for watcing
Very good to see someone with experience explaining how it should be , after 40 years on site it’s getting harder and harder to fine people that understand the 100% importance of getting it right , nice to see 👍
Thanks
I'm a roofer.. excellent...always something to learn...
Thanks anything you would like to see? i'm running out of ideas
Great video Steve. The biggest problem for extensions, loft conversions, etc is that most clients don't employ an Architect or Architectural Technologist post planning (in my experience) which is where all these important details are captured. It's a cost saving exercise by the client and typically driven by Builders/Contractors who tell them they know what they are doing and don't need the post planning input.
Perhaps but nobody explains to the customer that they need working drawings with lots of details and the reason seems to be to fold, Architect or Architectural Technologist (Using your works) would lose the job as they would be too expensive and if they don't give working drawings they cant be held responsible for making a mistake perhaps I'm cynical!
I think you’ll find most Architects/Technologists will explain to the client they need post planning detailed design. They’d be stupid not to as they are losing out on the work if not. Everything is about money and if the client thinks they can save some then they will.
Nice to see someone who takes pride in their work 👍
Thanks
superb video
Thanks
If the coping stone shouldn’t be bedded to the DPC with mortar as they don’t bind, what do you use?
Thanks
You use a DPC (damp proof course) that is made to be used under light loading and is sand faced so that it douse bind
I'm a 66 year old brickie . The standard of brickwork nowadays is disgusting . Seem to be more concerned with CS cards than actual skill or pride in work .
Yes I can agree with you on that its easier to to control as you don't need skilled people to control it
Im no expert infact far from 1 somehow just stumbled across ur video. I do have a question tho. If the damp proofing membrane needs to over hang 5mm plus go end to end of the brickwork when u cement the coping stones on surely ur just sticking them to the plastic membrane?? Ur stated urself in the end of the video that cement doesnt stick to plastic?? Im confused
I find it hard to find anybody that thinks its a good idea probably the suppliers of the insulation !
Will you stop. Insulation shouldn’t touch outside wall. !!!!!!!!!!!!!!!
Depends on the construction method really.
There is certainly products out there that can be built like that
Yes I think there should alway be an air gap between the cavity wall insulation and the outside skin and that cavity should be vented
You can full fill a cavity with rock wool or blow cavities with micro fibre
Advise required, on a sloped roof where is the leading flashing of the water gate meant to sit in relation to the damp course, above or below it?
would have to see a drawing to answer that
Excellent video! My parent's parapet wall has exactly the same problems that you have highlighted. Appreciate you sharing your knowledge and advice. Do once weathered coping stones let water through over time? The ones on my parent's roof are pitted and there are some traces of rusty water stains on the surface. I believe these coping stones are re-enforced?
Theoretically concrete coping stones are pretty water resistant and on top of this if you have a proper damp of course under it then you haven't got a problem however overtime some very old coping stones to let water get through the main problem is always at the joints
Cavity walls must NOT be bridged with insulation !
very informative and well explained.
Great video and amazing help!!
Thankyou
Having worked in the industry for many years on the merchant side the that'll do mentality is rampant in large construction as well as jobbing builders.
So knowledgeable mate, as a building surveyor these types of videos are absolutely brilliant. Subscribed !
Welcome aboard!
Hi Steve. I know you said have the dpc wide enough to overhang 5mm each side which sounds perfect but do you ever worry about water creeping back along the underside of the dpc? I think I came across this once in a different situation but similar application where driving wind was causing water to creep along the underside of the dpc rather than drip off the edge. I wonder if it could be bent down and/or use sealant right along each edge to prevent this? Perhaps not needed though
Not needed if you do the 5mm and coping stones correctly basically at the point you are talking about you are already at the second line of defence you are assuming that the coping stone drip has fail and water is tracking back to the wall below the coping and above the DPC. It then has to drop down to the DPC (damp proof course) and trackback again! can happen but where do you stop Two lines of defence has proved to be the way to go for hundreds of years. Just do them correctly
Great video pal. Every time I see remedial work going on to fix damp issues I think to myself that doesn’t look right and although I understand these things in theory having a video where the problem can be seen and then how it should be done makes it so much clearer. Great stuff 👍
Thanks
Really informative, well done.
Glad it was helpful!
I think the the way of building homes in the uk is very outdated and obsolete .. no disrespect intended many good bricklayers there it’s just the way of working there is the opposite how we do things here
Also think glass or rock wool is not a good insulation to use in a cavity and cavity needs to have a airpocket between the insulation and your outside bricks
Bricks do get soaked and so the insulation will with all the moisture as a consequence.. ties ins also needs attention they need not to transfer water to the inside of the building
Yes I can agree with most of what you say rock wool is ok in acaverty if its not fully filled
Thanks for clarifying these technical points. We, architects, tend to assume that builders would know these rules as basic standard practice... Difficult to be there at all times behind their back though.
Unfortunately no training so supervision is a must
In North America [U.S.A. and Canada] you cant just start a building before Plans are submitted and City or County Permits are signed off but prior same soil samples are depth of footings Calculated and number of same the amount and design of Rebar planned and calculated, correct spec of Slab, Contractors Permits insurance and Tax Certs checked all the while Building Inspector looking over your neck at various times through out the construction process, walls erected mainly timber Structural walls inspected for Codes, and internal Stud walls once erected inspected , Inspector checks same everything the likes of Fire Stopping ,Electrical, Mechanicals Plumbing & Civil seeing that there is a serious degree of compliant work according to submitted Plans and specs, the thing is City Hall and the County would be liable if things went south and would go after the Contractor via his liability Insurance or through the Court... very few Dodgy Davies plying their Trade.
There is no cavity. Shouldn’t the insulation be 50mm. There is no air gap.
I agree but they allow fully filled cavity now, what has been talked about in the comments is can you fully fill a cavity with solid insulation or does it have to be fluffy stuff?
I’ve just built an extension with a parapet roof and didn’t overhand my DPC. I left it flush. Building inspector signed it off no problem. Mistake on my side 🤦🏻♂️
building control is not there as a clark of works more of a health and safty
Hi Steven, Question for you regarding bedding of the Iko DPC at time stamp 5:22. Is a bedding layer of mortar laid on the bricks followed by the Iko DPC laid directrly on to the mortar. Then another layer of mortar for the bedding for the capping stones?
eventually
Really explains it well.
Unfortunately, due to the designed shortage of housing, new houses are often not checked properly either during or after construction. I'm a decorator and I try to stay well away from buildings made during the last 20 years due to the piss poor build quality. Seems anyone can call themselves a builder and throw up some houses these days🤷♂️
Great vid 👍
Yes I would never buy one
Really useful thank you. My issue - building early Victorian. Tiled pitched roof falling into a gully that abuts a parapet wall - 350 mm wide. Solid wall construction. The gully has for years been patched with felt and Acrypol to stop water ingress. The parapet wall has no coping stones. The interior wall has been very damp - large exposed wall externally but we believe due to historically water ingress and cold bridging. Want to future proof an ongoing issue for issues. Builder has proposed rather than removing the existing gully as it is sound he could over baton the the existing, lay OSB board and felt. He would also baten out the side of up stand of the parapet wall, the OSB and felt and add Alumasc on top of the wall. Is over boarding the existing going to be an issue with condensation as it's on top of the existing gully finish. Quite a difference in disruption and therefore cost in pulling out the existing gully. Would I be better to just ignore the additional batons to the top of the existing and add more felt. To make the interior a liable space I have already had the interior wall lined and insulated.
I thought this was lee and dean off channel four, amazing - can’t tell if this is comedy or not “vapour barrier” Hilarious- good work
Its comedy
Your explanation was ok however your explanation of a cavity tray was incorrect. If a cavity tray was fitted correctly with weep holes this problem is irradiated.
Not if the problem is not coming from the coping stones but because of thermal bridging under the cavity tray
It is unlikely to be architects giving the poor specifications because we have to be qualified and trained to above masters degree level and registered with not less than two full years experience. The poor specifiers are far more likely to be the architectural designers/consultants, plan-drawers etc with very little or no training whatsoever. Please do not confuse the two.
The claim is still ongoing with the architect's PI insurance as the speciations were incorrect however the builder added to the problems but he has long gone.
Could also do with a drip channel on the underside of the coping stones to direct rain water away from the brickwork. Spoke too soon. Bring back the Clerk of Works.
Yes needs slightly wider coping stones
Thank you for putting up this video- took a bit of time I reckon 👍🏻
Q: how do you dry out a wet cavity after you find it?
Because the builing was relatively new the insurance company will be involved and we don't always get to do the reconatution or the drawing out, also sometimes it takes years for a decision to be made on how to fix the problem. On this property I know the work still hasn't been undertaken, the insurance company don't want to pay for the works probably round £100K ! the customer cant sell the property and its all a bit frustrating for them.
That building looks like it needs to be dismantled and rebuilt!
Yes looking like it needs some major work
Mechanical fixing of copings? (Great vid)
Yes it will be really hard to do
incredibly informative
Thanks
As an insulation engineer to trade I've never liked CWI, that air gap is there for a reason, by all means insulate the outside walls but stuffing that cavity is a not a good idea in my experience.
A lot of comments below on that and I also agree
Used to see this all the time snagging for a international orangey company that’s now folded .. incorrect trays or no tray At all on parapet walls ..
it’s crucial to use the correct tray that’s one piece or welded at the corners … Because the design detail on most used to rebate the doors sometimes you would end up with 6 or 8 angles that would leak ….
Things have got complicated on building sites
I was just wondering, isn't there any ventilation in the cavety walls?
I think cavity wall should be vented but they are not !
Hi where are you based... do you cover West Yorkshire
London and the surrounding area I get lots of people wanting me to go all over the place mostly UK but secondly the USA!
Great analysis.
Edit: anyone in the building industry can tell you if they are honest that most contractors are cowboys. Also, supervision??? Do you think that 99.9% of the so called supervisors in the UK are actually qualified? If the industry was healthy you would require an actual Civil Engineer on site to oversee the works. As in qualified from a reputable University. Or does anyone think that the guy who started off as a labourer then became a ganger to a foreman to a site manager to a project manager to a contracts manager know or understands what he is talking about. Seriously. You would not find this behaviour in Medical or Law.
I'm sorry but what?
This is exactly what happens in law and health for a large number of people working there way up and training as they go it's the vocational route.
It's more and endemic issue with most trades that as we up the standards we don't take everyone up a notch.
In the UK the government has been useless with getting better standards and training in place.
So to blame those who came though the ranks is pretty harsh.
Another major culprit is money. Cheapest contractor often wins.
A civil engineer is ground works, structural engineer or architect I think you mean. And there are plenty of medical malpractices goes on un investigated. Don't get me started on private clinics or dentists back in the 70s and 80s.
Ay Steve? Dr wise allways had brand new Mexico S and harriers
@@peteramberley9952 no. There is a misconception of what a civil engineer is here in the UK. Civil Engineer is not drainage or earthworks and groundworks companies that say civil engineering have nothing to do with civil engineering.
Architects are completely different occupation.
A structural engineer is a civil engineer who maybe designs mainly or only structures. It wrong to differentiate and say that a civil engineer is not a structural because the degree is one a d the same. Maybe one can do masters in civil engineering and choose more structure modules and get a Structural engineering MSc but in reality there is no difference. I met a drainage layer once that he was saying he puts on his CV that he is a civil engineer. How preposterous is that?
@@TheWebstaff so what you are saying is I can start off as a janitor in a hospital and then get promoted to a nurse and then a GP and even perform surgery.
Get out of here.
@@ΜαρίνοςΤ-μ4ρ Lol am I being schooled in my own country by a kosavan?
that render is the worst so the rest probably is. condemn the lot looks like they have used light weight blocks on external coarse its all doomed 😀
I think its all got to come down also
That's why new builds are an absolute sh....t
Yes I wouldn't buy one unless it was about 2o years old
This is why cavities should be there as cavities.
Yes correct
Excellent video thank you
Glad you enjoyed it
Great video Steve. We live in a 1970s end of terrace house in East Kent with a parapet wall with coping stones. Every time we have heavy rain the water gets into our property especially at the rear, water into back bedroom, dining room and porch. Roofer says he can fix the problem by putting felt over the coping stones without taking stones off. What do you think? Thanks Tom East Kent
I think Felt over the top of coping stones is a very good option. It doesn't look good but it's quick cheap and works for a long time.
Would Cromopol have the same desired effect and easy to apply even for me@@SteveRoofer
Where,s the lead under the coping stone ??
Whay would there be lead under them?
Finally someone with solutions and speaks english( simple and concise) thanks
Just a question there is different types of cavity wall insulation some is the loose one just injected into the wall. Does the same problems happen to them too. Internal sweating(thermal bridging) I think you said or the damp proof and coping stones leaking into it?
Its going to be down to the build and how good it is if there is cavity wall trays fitted and a good DPC (damp proof course) however I don't like fully filled cavity think that a mistake
See it happening all the time on sites, people dont give a shite anymore
Yes I agree even the management
Excellent information.
Glad you think so!
I covers inspections for the NHBC, the annount of poor quality workmanship I see on new builds is absolutely amazing, particularly on roofs, flashings, copings etc
Couldn't agree more!
quality mate no nonsense just fact
Thanks
Great video , do you cover Oxford
I did a huge project in Summertown some years back. Send over info
Hello from Switzerland. I am not a fan of Stone parapets. I wonder, why not use metal, where joints are overlapping or seamed.
Stone or metal they hall have to be fitted correctly
@@SteveRoofer true that👍
Had customer with exact same problems before, usually expecting failed upstand flashing or copings failing
Its a common problem
Brilliant video and explanation
Many thanks!
Full Fill kingspan is piss poor and it shouldn’t be used in are damp climate. and its a nuisance to build with. Full fill rock wool or use Celotex with a 50mm cavity or even better get it pumped once superstructure is built
I think the industry is coming to the same conclusion
@@SteveRoofer I hope so. Long ago Britain had the best architecture in the world. Now look at what we build 😣 complete shite. Built by line rats with zero care given.
Looks like a relatively new house too. I’d be fuming if I’d bought that crap
Two or three years
Subscribed,
I remember when a Cavity wall was for a Cavity.
Good point
at the end it says 'cement wont stick to plastic' ....... At the start the damp proof was plastic and you stated it just wasn't wide enough ? would the plastic damp proof the correct width have worked with the coping stones or not ??
No probably not as the coping stones to move and slip on the plastic
@@SteveRoofer so what product would be used instead ?
Do a video on lead aprons on the cavity wall buddy
While on sites I’m noticing many low levels leaking but the roofs are fine it’s always the cavity trays not working properly
A video on this would do well
Thanks for the idea
It's just pure laziness
and a lack of ownership of what people are doing
Was this a " new build "?
Yes
As a roofer of 2 years I'm yet to come across a damp course under the copings we mostly are on very old buildings but most of these copings and buildings don't have the damp issues or why is this ? Is it due to the lime mortar that allows it to breathe or is it because the cavities don't have that insulation and some.of the very old ones are just rubble.filled cavities
Im looking at jobs that have gone wrong there must be lots out there that haven't gone wrong but are still not build correctly and the good old roofs and copings normally have slate DPC build in your jst not seeing them
@@SteveRoofer ah yes I've seen the slates under the copings and I've seen felt over the cavity onto the wall come to think about it.👍 Good stuff mate thanks
Nice advice. I was just wondering what will become of the wet insulation? Will that be removed, dried and replaced ?
No thrown away you can't dry it also the external wall will probably have to be taken down
Awesome I was wondering why all the paint was coming off the house up the road great info 👍👍
Glad you enjoyed it
Great example showing why you should employ an architect. Not only to draw and note all of this up correctly, but also to run the job. Ensures that poor workmanship can be called out where necessary and gives the client peace of mind.
Its not a architect that needed so much as supervision on site
A well informed and highly competent analysis of the problem.
You are right to blame poor specification, bad building and non-existent inspection that is endemic in the industry but to give some defence to the specifier a comprehensive specification along with all the details for all elements (e.g. an NBS), even for a simple domestic extension, would fill a lever arch file and clients are unwilling to pay for such detail and more worryingly builders don't read it. Specifiers rely on the builder being competent and not having to be told how to build the basics. Certainly on domestic work clients rarely want to pay for inspections, putting their trust in the builder who is often simply not sufficiently trained or competent to carry out all the operations expected. Most times if I mention the correct way to build a detail I either get blank stares or BS as to why it should be done different. Its a breath of fresh air when a builder knows what he is doing.
I think you sum things up perfectly
Hi Steve, Great information as usual.
Sorry about the other post with a 'P'
Let me start by stating I am not a builder or am I any way involved with the building trade, and I have no intention of doing so either.
I wonder if you could indulge my curiosity about those coping stones at 3.15 in your video, they look to be on a 45 deg slope or thereabouts.
If you had a dampcourse under them that had 5mm sticking out either side of the brickwork below, how do you stop them all sliding down the slope?
Surely any cement above the dampcourse may be bonded to the coping stones but wouldnt be bonded to the dampcourse would it? and surely its not relying on friction is it?
My guess would be that there would be some pins stopping this happening at the bottom of each coping stone, but then they would penetrate the dampcourse, no?
Like I say, I am not an expert in any of this, it's just a thought that popped into my mind when viewing the video.
All good points. Sand and cement at and angle will not slide when wet if applied correctly. The new DPC (damp proof course) im using is slightly grippy so that helps it all stick together the plastic one although looks like its grippy isn't. As regards mechanically fixing this is becoming something that building control and the BS standards are starting to ask for however your point about piercing the DPC is extremely valid. Not only that nobody seems to have thought about ht ejujoling act the builder or roofer will have to go though to do this. place wet cement down then a DPC then drill though it all then bed a coping stone and aline everything ! its not going to happen in a good way. Any construction method should be simple and robust
I am by no means an insulation expert but I always thought natural draft between the insulation and outer wall is key to keeping everything dry.
So what I'm seeing here is the insulation is touching the inner wall as well as the outer wall which in my simple brain is waiting for problems to occur.
Yes I would prefer to see the cavity vented
Glad I watched this. I’ll always remember this video
Thanks
Great information Steve and very useful to me as we have a parapet wall to do soon and i've been trying to get a specification for it beyond the minimal info on the drawings, i.e. "continuous DPC to parapet wall with cavity trays over openings". That's literally all it says.
Glad it was helpful!
Nice video. You sound like a true professional and someone knowledgable about his trade. I had a similar issue which created efflorescence on the inside wall. When I got the coping changed I put my hand in the cavity and noticed the insulation was wet. The builder did use damp proof but not as well as you have suggested in your video. This resolved the issue around 50%. I then used efflorescence treatment after sanding down the wall. The seems around 90% sorted. Its so difficult to find good roofers/builders. Your video just popped up but I am now subscribed.
Thanks
Do you need to add dpc over the gable end cavities for a detached house with no copings, just slate over hanging the upvc verge?
Does a gable end cavity need closers added?
First you should do as the experts tell you and the details should be on your drawings ( fat chance) My personal view would be something like this. The cavity is being used as a line of defence to stop ingress of water from outside mainly rain. The cavity has probably been backed fill with insulation partially or fully. The cavity coud and in most cases will get damp. We install cavity wall trays to take care of draining excessive moister. Therefore it stands to reason the cavity should be vented therefore I would leave it open or vent it top and bottom. Thats my opinion.
Would you suggest a mechanically fixed coping detail much like the mechanical fixed approach to ridge and hip tiles to avoid the issue to mortar needing repointing over time?
Depends on the job but probably not just use the correct DPC and SBR in the mix
Hiya Steve, would you perhaps be interested in doing a brief inspection on the workmanship of a conservatory Ive had done end of 2021?
Great video, i can see you have the attention to detail I need.
Building and roofing surveys and reports are the things im doing all the time non. THe cost depends on the location and completely. email me over the details info@londonflatroofing.co.uk
Great video, sir!
The state of that shit
Yes not good there should have been a clark of works on the job
Very interesting i was in the building trade and learned a lot from this. Well explained.
Glad you liked it!
I never understand why they put it in the cavities. Just have it on the interior, no bridging issues then.
I don't think fully filled cavity should be allowed
Fantastic!
Well delivered, succinct and informed.
Great ammount of examples and solutions too.
Good work.
Glad you liked it!
You have fantastic knowledgeable videos. Keep up the great work.
Glad you like them!
There's a chance that insulation maybe 'seconds' having only foil on one side. It is out there and is a way to cut costs but unfortunately quality too.
Possibly
Really good video with good clear explanations.
Glad you enjoyed it!
Great video
Glad you enjoyed it
Lead a good way for the coping stones just need to prime it so the cement keys too it
yes we prime ours with SBR
Thank you for your valuable time ⏲
My pleasure
Well informed video great stuff
Glad you enjoyed it