Comments on: Damp Proofing a Basement by Adding a Damp Proof Membrane (DPM) http://www.oneworldcoffee.com/2008/06/26/damp-proofing-a-basement-by-adding-a-damp-proof-membrane-dpm/ Sat, 13 Mar 2010 01:42:16 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: MCH http://www.oneworldcoffee.com/2008/06/26/damp-proofing-a-basement-by-adding-a-damp-proof-membrane-dpm/comment-page-1/#comment-54402 MCH Sat, 13 Mar 2010 01:42:16 +0000 http://www.oneworldcoffee.com/?p=41#comment-54402 I've read your tanking solution. I like your dedication. Possible bad news - did you consider that you will cause condensation. Basically the water vapour in the warm air in your habitable space makes its way through the plasterboard, through the quilt insulation and can condense on the cold black plastic that sits against your outer wall. The condensation will then run down to the bottom of the plastic sheet where it can appear as if there is a leak. If you do a condensation risk analysis using freely available software like builddesk you'll see my point. The solution is to have a vapour barrier on the warm side of the insulation. Pay particular attention to electrical outlets etc, the membrane should pass behind then and any holes for cables be sealed. Because the vapour barrier is on the warm side of your insulation the surface temperature of it will not allow condensation to form. A further comment on the outside of the wall - if you can get to it - place a geotextile membrane against the wall, then some gravel. If water gets to it, it can drain away to the bottom - where of course you may still have to deal with it or encourage it to run to a natural sump. I’ve read your tanking solution. I like your dedication. Possible bad news – did you consider that you will cause condensation. Basically the water vapour in the warm air in your habitable space makes its way through the plasterboard, through the quilt insulation and can condense on the cold black plastic that sits against your outer wall. The condensation will then run down to the bottom of the plastic sheet where it can appear as if there is a leak.
If you do a condensation risk analysis using freely available software like builddesk you’ll see my point. The solution is to have a vapour barrier on the warm side of the insulation. Pay particular attention to electrical outlets etc, the membrane should pass behind then and any holes for cables be sealed.
Because the vapour barrier is on the warm side of your insulation the surface temperature of it will not allow condensation to form.

A further comment on the outside of the wall – if you can get to it – place a geotextile membrane against the wall, then some gravel. If water gets to it, it can drain away to the bottom – where of course you may still have to deal with it or encourage it to run to a natural sump.

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]]> By: rita http://www.oneworldcoffee.com/2008/06/26/damp-proofing-a-basement-by-adding-a-damp-proof-membrane-dpm/comment-page-1/#comment-43145 rita Thu, 13 Aug 2009 17:46:43 +0000 http://www.oneworldcoffee.com/?p=41#comment-43145 JJM could you tell me any surveyor who specializes in remedial works of this type in Manchester area?I'm already buying a basement flat and we found there is a problem with penetrating dampness in the front wall and the waterproofing system wasn't installed properly! regards JJM could you tell me any surveyor who specializes in remedial works of this type in Manchester area?I’m already buying a basement flat and we found there is a problem with penetrating dampness in the front wall and the waterproofing system wasn’t installed properly! regards

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]]> By: JJM http://www.oneworldcoffee.com/2008/06/26/damp-proofing-a-basement-by-adding-a-damp-proof-membrane-dpm/comment-page-1/#comment-39128 JJM Tue, 23 Jun 2009 16:08:56 +0000 http://www.oneworldcoffee.com/?p=41#comment-39128 We recently had the managing agents of our building throw a quote of £12k for basement damp proofing with a local company (one of the most established in the town) in East Sussex. The building also had to DPC as it was built in the early 1800s. The damp proof company completely over-blew the spec. We, the leaseholders, employed an independent damp proof specialising surveyor. He said half of the works were completely unnecessary, and the other half were inappropriate. We saved £7,000 on the damp proofing, which goes to show that one shouldn't always trust a specification drawn up by a 'reputable' damp proofing firm. Get an independent surveyor who specialises in remedial works of this type (there are only about 12 or so in the whole of the UK) to draw up a spec and then get the quotes based on that. Their is an obvious conflict of interests if those specifying the works also do the job. We recently had the managing agents of our building throw a quote of £12k for basement damp proofing with a local company (one of the most established in the town) in East Sussex. The building also had to DPC as it was built in the early 1800s. The damp proof company completely over-blew the spec. We, the leaseholders, employed an independent damp proof specialising surveyor. He said half of the works were completely unnecessary, and the other half were inappropriate. We saved £7,000 on the damp proofing, which goes to show that one shouldn’t always trust a specification drawn up by a ‘reputable’ damp proofing firm. Get an independent surveyor who specialises in remedial works of this type (there are only about 12 or so in the whole of the UK) to draw up a spec and then get the quotes based on that. Their is an obvious conflict of interests if those specifying the works also do the job.

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]]> By: Renovation Dave http://www.oneworldcoffee.com/2008/06/26/damp-proofing-a-basement-by-adding-a-damp-proof-membrane-dpm/comment-page-1/#comment-20157 Renovation Dave Sat, 13 Dec 2008 23:11:17 +0000 http://www.oneworldcoffee.com/?p=41#comment-20157 Thanks for the comment Handyman :) We added a damp proof membrane between the woodwork and the brickwork (in some areas it was between the woodwork and the plasterboard which wasn't as ideal) so the plasterboard shouldn't absorb much moisture (impossible to remove moisture completely). The only place water can get to the plasterboard from the original brick walls is via the plasterboard screws that are screwed into the wood. So the moisture has to go through the wood then through the screws which is unlikely. When we removed some of the original woodwork the majority of the nails used didn't have rust on them where the nails went through the wood, so even in the worst areas the worse case scenario will be moisture entering the wood work and all wood was treated. Obviously if we wait long enough it's going to fail, but I expect the plasterboard to be damaged and require replacing before the woodwork does. We used the original woodwork on some of the walls which in hindsight I wish we'd have replaced it all. In other areas on the house we have replaced everything. If the basement last 25 years with no damp problems I'll be happy, so far it's lasted over 2 years with no signs of rising damp. Only problems been condensation due to the TV nook (old fireplace area) and not insulating it, basically it's a cold spot at the bottom due to no insulation and only one brick thick wall (rest of wall two bricks thick). We added a bit of cladding over the area with a inch thick insulation (used polystyrene sheets), this has improved the condensation problem in that area, not completely still a cold spot. Other than that there are no other signs on damp in the basement which is a major improvement over what it was like before we started, so I'm happy. Most important thing is when we are in the basement you barely need any heating on due to the insulation, really holds the heat well. David Law Thanks for the comment Handyman :)

We added a damp proof membrane between the woodwork and the brickwork (in some areas it was between the woodwork and the plasterboard which wasn’t as ideal) so the plasterboard shouldn’t absorb much moisture (impossible to remove moisture completely).

The only place water can get to the plasterboard from the original brick walls is via the plasterboard screws that are screwed into the wood. So the moisture has to go through the wood then through the screws which is unlikely.

When we removed some of the original woodwork the majority of the nails used didn’t have rust on them where the nails went through the wood, so even in the worst areas the worse case scenario will be moisture entering the wood work and all wood was treated. Obviously if we wait long enough it’s going to fail, but I expect the plasterboard to be damaged and require replacing before the woodwork does.

We used the original woodwork on some of the walls which in hindsight I wish we’d have replaced it all. In other areas on the house we have replaced everything. If the basement last 25 years with no damp problems I’ll be happy, so far it’s lasted over 2 years with no signs of rising damp. Only problems been condensation due to the TV nook (old fireplace area) and not insulating it, basically it’s a cold spot at the bottom due to no insulation and only one brick thick wall (rest of wall two bricks thick). We added a bit of cladding over the area with a inch thick insulation (used polystyrene sheets), this has improved the condensation problem in that area, not completely still a cold spot.

Other than that there are no other signs on damp in the basement which is a major improvement over what it was like before we started, so I’m happy.

Most important thing is when we are in the basement you barely need any heating on due to the insulation, really holds the heat well.

David Law

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]]> By: Handyman http://www.oneworldcoffee.com/2008/06/26/damp-proofing-a-basement-by-adding-a-damp-proof-membrane-dpm/comment-page-1/#comment-20117 Handyman Sat, 13 Dec 2008 14:32:59 +0000 http://www.oneworldcoffee.com/?p=41#comment-20117 what you have done about damp proofing is ok because its your house and you will see the result. you sound like a sensible guy but i just wonder why you choose to put insulation between the wall and plasterboard? that insulation itself is going to transfer the damp from the wall to the stud! does that make sense? what you have done about damp proofing is ok because its your house and you will see the result. you sound like a sensible guy but i just wonder why you choose to put insulation between the wall and plasterboard?
that insulation itself is going to transfer the damp from the wall to the stud!
does that make sense?

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]]> By: Renovation Dave http://www.oneworldcoffee.com/2008/06/26/damp-proofing-a-basement-by-adding-a-damp-proof-membrane-dpm/comment-page-1/#comment-8879 Renovation Dave Fri, 18 Jul 2008 16:43:08 +0000 http://www.oneworldcoffee.com/?p=41#comment-8879 Why do you assume this was about saving money? In time terms it was far more expensive than hiring a company to come out and inject a fresh chemical damp proof course, but we plan to live here for a long time and I want the job done the best way possible under the circumstances (best way would be knock the house down and start again :)). As I see it if this fails my first course of action will be to add a plastic damp proof course on the outside bricks that cover 3 of the 4 sides of the property, (I might do this long term anyway as will add to the damp proofing) if having a plastic damp proof course on both sides with the new damp proof bricks isn't better than getting a company to drill a hole every brick and inject a chemical in hoping it will form a water proof barrier I'd love to understand why? I've read research that the injection damp proof course is far from a perfect solution to damp proofing and fails often, added to that the last attempt at a chemically injecting DPC failed (and failed badly!) in under 10 years I don't have much confidence in that form of damp proofing! I was concerned about the under-ground part of the house as that had a great deal of damp (wet to the touch) and also know the latex paint will fail eventually. So far it's holding up well one year later, and taking into account the tanking like thing we did even if water does get through the latex paint (and it will eventually) it won't get through the plastic DPC sheet between the wall and anything that could be damaged by water: unless you think the 1200 gauge DPC sheeting will rot quickly? I temporarily patched a hole in an old shed roof outside over a year ago and it's still doing the job despite being in the sun and rain for over a year. If what I've done generally lasts 25+ years and that one major problem area lasts 10+ years I'll be very happy with the result. The basement of the house has been transformed from unlivable to very comfortable. Could you imagine a builder as a matter of course adding several inches on insulation to all walls (and using 1200 gauge DPC sheeting just in case)? Insulation isn't that expensive, (was around £15 a roll, the 1200 gauge DPC sheeting was ~£30 a roll) but when using it to coat walls as well as ceiling spaces (we've insulated every space we can) it adds up. This was done for our comfort, wasn't about saving energy in the winter to save money per se (all these types of improvements takes decades to pay off in fuel savings), was about having a house that didn't have big drafts in winter and would be cool in summer. It's working so far, middle of summer and I have a lovely cool basement to live in (we haven't bothered using fans this year not needed). David Law Why do you assume this was about saving money?

In time terms it was far more expensive than hiring a company to come out and inject a fresh chemical damp proof course, but we plan to live here for a long time and I want the job done the best way possible under the circumstances (best way would be knock the house down and start again :) ).

As I see it if this fails my first course of action will be to add a plastic damp proof course on the outside bricks that cover 3 of the 4 sides of the property, (I might do this long term anyway as will add to the damp proofing) if having a plastic damp proof course on both sides with the new damp proof bricks isn’t better than getting a company to drill a hole every brick and inject a chemical in hoping it will form a water proof barrier I’d love to understand why?

I’ve read research that the injection damp proof course is far from a perfect solution to damp proofing and fails often, added to that the last attempt at a chemically injecting DPC failed (and failed badly!) in under 10 years I don’t have much confidence in that form of damp proofing!

I was concerned about the under-ground part of the house as that had a great deal of damp (wet to the touch) and also know the latex paint will fail eventually. So far it’s holding up well one year later, and taking into account the tanking like thing we did even if water does get through the latex paint (and it will eventually) it won’t get through the plastic DPC sheet between the wall and anything that could be damaged by water: unless you think the 1200 gauge DPC sheeting will rot quickly? I temporarily patched a hole in an old shed roof outside over a year ago and it’s still doing the job despite being in the sun and rain for over a year.

If what I’ve done generally lasts 25+ years and that one major problem area lasts 10+ years I’ll be very happy with the result.

The basement of the house has been transformed from unlivable to very comfortable. Could you imagine a builder as a matter of course adding several inches on insulation to all walls (and using 1200 gauge DPC sheeting just in case)? Insulation isn’t that expensive, (was around £15 a roll, the 1200 gauge DPC sheeting was ~£30 a roll) but when using it to coat walls as well as ceiling spaces (we’ve insulated every space we can) it adds up.

This was done for our comfort, wasn’t about saving energy in the winter to save money per se (all these types of improvements takes decades to pay off in fuel savings), was about having a house that didn’t have big drafts in winter and would be cool in summer.

It’s working so far, middle of summer and I have a lovely cool basement to live in (we haven’t bothered using fans this year not needed).

David Law

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]]> By: Carey Keates http://www.oneworldcoffee.com/2008/06/26/damp-proofing-a-basement-by-adding-a-damp-proof-membrane-dpm/comment-page-1/#comment-8878 Carey Keates Fri, 18 Jul 2008 15:34:30 +0000 http://www.oneworldcoffee.com/?p=41#comment-8878 I think I have just read a horror story - and you sound so pleased with the "result"! Firstly, you think you've saved money by not using a specialist. Maybe you have, if you don't count the hours spent on it by your son. But have you made it damp-proof? I doubt it. Then there's the below-ground room. Yes, you are quite right, if the walls are below ground, they are subject to water pressure. Painting some stuff on the inside may work for a while, but water pressure will push it off in time, probably when it will be least convenient. (Such coatings are designed to be used when water is on the inside, forcing the coating onto the wall). My advice: swallow your pride, put your hand in your pocket, and employ a reputable firm of damp-proofers (check that they are members of the BWPDA). They will not only do the job properly, but should also give you a guarantee. Then enjoy the (dry ) house, and relax. I think I have just read a horror story – and you sound so pleased with the “result”!
Firstly, you think you’ve saved money by not using a specialist. Maybe you have, if you don’t count the hours spent on it by your son. But have you made it damp-proof? I doubt it.
Then there’s the below-ground room. Yes, you are quite right, if the walls are below ground, they are subject to water pressure. Painting some stuff on the inside may work for a while, but water pressure will push it off in time, probably when it will be least convenient. (Such coatings are designed to be used when water is on the inside, forcing the coating onto the wall).
My advice: swallow your pride, put your hand in your pocket, and employ a reputable firm of damp-proofers (check that they are members of the BWPDA). They will not only do the job properly, but should also give you a guarantee. Then enjoy the (dry ) house, and relax.

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