Damp on an inside wall - how to approach it?

[Lovecat]

I was wondering if anyone had been in this situation and how best to find out a) what the hell is causing it and b) what to do?

(sorry, this is a bit of an essay...)

We have a Victorian terrace where the original kitchen was in a one-storey extension (although part of the original building) at the back of the house, making the back of the house an L-shape.

What was the original morning room,which the kitchen leads off from, is now our kitchen and the original kitchen is a downstairs bathroom, with a fake wall creating a small vestibule and cupboard between the two rooms - hope this makes sense! I'm going to attach a pic to my profile which I hope will show what I mean.

Anyway, the back wall of our kitchen (the old morning room) had damp in it when we bought it. On the advice of the survey, a damp course was installed and it kept dry for about 4 years - when damp returned, it was still under guarantee so it was done again. Ffwd 5 years and the damp returned. By now I was fairly convinced that something other than 'normal' rising damp was causing this, especially as the interior wall of the vestibule was also damp and the plaster was coming off in lumps. Inside the cupboard was also now damp.

We have our pipes covered by British Gas and when they came out, they found that a pipe that ran from the kitchen sink (next to the interior wall) beneath the exterior wall and out to the drain had a leak in it. The floor was ripped up, the pipe fixed, new floor put down, replastered, repainted, end of problem, or so we thought.

Although the exterior wall was now dry, the cupboard was still damp on the floor and in the wall. Further investigations showed a slow leak under the bath. This too was fixed, we borrowed a dehumidifier and dried it all out, it seemed to be fine. The BG man could not find any more leaks anywhere else.

I know we've just had the wettest weather ever, but the damp is now back. All the airbricks are clear, there are no pipe leaks, the roof is sound, but yet again we have plaster and woodwork going rotten, tiles falling off the kitchen side of the cupboard wall with damp - this is driving me insane!

Short of demolishing the place and digging up the foundations, how do we find out what is causing this problem? We're hoping to put the place on the market this year, and although, yes, we could get another damp course slapped on and paint over it, hoping that nothing else causes a problem, I would feel bad doing this and if it comes out in a survey it's going to cause problems.

So what do we do? Would a surveyor be able to pinpoint the cause, or would they just advise another damp course? Are there specialists for this? I'm really not sure where to go from here (or how much it's going to cost us )

If anyone's had any experience of this or knows what to do, your help and advice would be very gratefully received! :)

There are specialists but you need to get someone with experience in old buildings, not someone who will just try to sell you another damp proof course.

In our house it was finally pinned down to being a problem with the wall being painted in unbreathable masonry paint, so the damp got in and couldn't get out again. Could it be anything like that? Only someone who really understands old buildings is going to pick up anything like that so it is really important you don't get a damp proofing firm to do it.

Thanks Tunip - it won't let me attach a picture, so I'm hoping what I've written makes sense. How do you find a specialist - would it be a damp specialist, a surveyor...? Sorry to sound clueless, but everyone I've googled in the area is linked to providing damp courses... :(

is the wet just in an outside wall? Does anyone drape wet washing around?

As it's a kitchen, a plumbing leak is very common. Is it a concrete floor? How do you know there are no leaks?

Is the wall wet on the outside? Have you stood outside during rain and looked for overflowing gutters?

Hello PigletJohn :)

It's in the outside wall and the inside wall that would be a continuation of the same wall in the L-shaped bit if it didn't have a doorway in it (I hope that makes sense!) The inside wall faces into the kitchen, the other side of it is the inside of the cupboard (which is damp too).

Since the leak beneath the floorboards was discovered, I've not put washing on that wall (there is a radiator beneath a window).

The floor is an unholy amalgam of floorboards, concrete and chipboard nailed over joists. The area where the damp is is wooden floorboards. When the original leak was uncovered we had joists replaced as they were rotten.

The wall isn't wet on the outside, all gutters are sound (we had them cleaned in November). The roof was checked for loose tiles and repointed in Nov/Dec. British Gas aka Dynorod are telling us there are no pipe leaks, we've had them out 3 separate times over this - although I have little or no faith in them. The original leak, I had to point out to them that when I ran the tap into the sink, nothing went down the drain outside - when the damp returned it was the first thing I checked and it all seems to be running through now.

HTH :)

have a look under those floorboards.

Have you got a water meter?

No water meter.

The floorboards are underneath stone-effect laminate which the insurance company-paid-for guy doing the floor repairs after the first leak recommended to cover the hideous floor (before that it was vinyl cushion-flooring). Is there no way of checking it without ripping up the floor again....?

I sympathise sounds like a total pain. i hear your frustration as we also have a few damp issues to resolve. Piglet John is right you need to go under the floorboards. To share our experience which may be or not be helpful...

bought house around 6 months ago, some damp walls. Have resisted temptation to inject walls. Our findings are :

-rubble under floorboards bridging slate damp proof course (naughty builders) we have removed around 5 bags and still going strong...

• The subfloor is basically too full of accumulated junk ...
• we have capped chimney pots with ventilated cowls to stop water coming down
• notice garden slight slope towards house, so need to sort garden drainage

-cement render on outside of house is was also bridging dpc to helpfully moving water up the side of the house. hacking it off

• concrete foundation in end of kitchen - shame this as i think one day i will need to dig it out and put in a suspended timber subfloor with air bricks
• also need to vent some closed fireplaces which have been boarded up

I have been slightly obsessed by damp for around 6 months now. Piglet john kindly suggested i look at all the above and true enough they are the source. it is slow work removing the rubble but it is surely breathing better and the smell is definitely gone/going. This is slow but satisfying.

We did have a surveyor look although i think an old buildings person is going to be more helpful.I am going to try and do the same.
i am always opening windows and heating on full whack all day which is i'm sure is expensive but it is really helping

Sorry for long post but thought it might be good to hear what we are doing- also victorian terrace.

we are not there yet but i think with some lime plaster and maybe a fireplace (will remove chimney caps.. for that) could be good in another 6 months or so.

best of luck

Thank you, ftb, that is helpful. Yes, it is very frustrating! :o

I think you and PigletJohn are right, I will have to get the floor up - nightmare! The chimneys are in the centre of the house so nowhere near the back wall, there's no damp around the chimney breasts so I'm hoping it's nothing to do with them. We have one open fireplace and the others have airvents. The patio definitely slopes away, the rain we've had recently has shown us that with the lake at the bottom of it where it meets the lawn!

When the floor was taken up the first time, the bloke commented that we had the world's biggest snail farm under the floorboards - probably because of all the damp! - and he did do some scooping out of muck. Bleh.

A friend has now recommended a surveyor she knows who has experience of old buildings, so I may give him a call and see what he suggests. I have lived with this now for over 15 years and am sooo fed up with it coming back every time!

Thanks again for all the suggestions :)

if you have a snail farm, it will not just be the damp, there will also be food. That might have come from a leaking sink drain or soil pipe carrying tasty particles. Red worms in particular indicate leaking drains. Shovelling out all the rubbish will help you see where it is coming from. It's nice if you have concrete oversite under the floor, but this seems to be more common on clay soils around London. Concrete oversite is not waterproof but it is fairly clean. A more modern house, depending where it is, might be on a concrete raft.

A modern concrete floor should include a DPM, so if it is wet, there is usually a leaking pipe. most likely the incoming main which is at higher pressure so comes out of a leak faster.