Covering up a damp interior wall ...

[Dave L]

There's a wall in my house that has been damp all the time I've owned the place. The damp can be felt up to a height of 4 ft or so. It has not been a problem for me because I painted it with damp-block paint. However, I now want to sell the property and I want to cover up the problem as best I can, so that it won't show up when prodded with a resistance tester. I don't have the time to try and cure the damp at it's source. Instead, I'm thinking about nailing damp-proofed battens to the wall and applying plasterboard to the battens - thus ending up with a wall that is completely dry on the surface, even when prodded with a resistance tester. Is this plasterboard-cladding idea commonly done, and is it efffective?

Thank you,

Dave

[BigWallop]

Covering the damp up isn't really a fix. You need to find out where the damp is coming from and fix that.

Is there a wall butted against the damp wall? Make sure the joint is water tight between the two walls, and that water isn't lying against the wall that's damp.

Is the ground level outside at the height, or just below, where the damp is appearing? Remove the excess soil or rockery planting area that is sited against the wall, this is more than likely the cause of moisture transfer through the wall.

Is the roof properly water tight and the guttering doing its job correctly? Check that water isn't running down the wall from where it should go into a roof guttering system. Make sure roofing covering is properly water tight and that any tiling or sealing system is fully intact and working properly.

Etc. Etc. Etc. Don't just try to cover it all up. It won't make it go away.

[Dave L]

Thanks for your suggestions. The guttering is not sending water down the wall. It's a very old house with cavity walls but no DPC. The ground level outside is about where it should be. The outside of the brickwork is painted in Dulux Weathershield, so there is not likely to be any rain getting through that. It looks like rising damp.

But does the damp really matter if it's not getting through to the interior once I install my proposed plasterboard cladding idea?

Dave

[BigWallop]

Once you install your interior cladding idea, your sealing the damp off from being evaporated into the surrounding air of room. Once sealed off, it will stink like the devils breath if it is allowed to grow mould in still air.

This type of damp needs plenty ventilation to stop it getting worse. You close off the vent, you make the problem worse. Even paints coverings can create a seal that holds moisture in the wall. This could cause the stone work to become soft and begin to crumble.

Have you had the floors checked to see if they cross to the outside wall? This could cause dampness to climb the wall.

Is the under floor dry? Are there any leaking drainage pipes in the area? Do you have a leak in the original heating system?

You say that the soil outside is in the right place. But is it? Have you try digging away some soil to see what's behind it against the wall? Digging some of the soil away and laying roofing felt against the wall, then back fill the soil to hold it, may help keep water from lying against the wall and climbing up.

There is more to it than just blowing it with a hairdryer and painting it. Get to the cause and repair it.

[Dave L]

It is already sealed off with damp-block paint. However, if you are saying that this will not be a perfect seal in every square inch of the wall, then you may be right...

That's how it's been for the past 12 years. No case of "all fall down" as yet.. ;-)

Yes. It's a suspended floor and the joists only enter the inside skin of the cavity wall.

No, it's very damp under the floor along the wall which is affected with the damp. The middle of the under-floor area however, is dry.

That's a possibility that I hadn't considered. How would I find out without digging up the road outside? ;-)

No - it didn't have a heating system when I first discovered the problem.

No - because it's very hard tarmac (council pavement).

But water climbing up the outside skin of the cavity shouldn;t affect the inside skin and the interior of the house, should it?

I'd like to... but it seems very hard to determine the cause. It's not obvious at all...

Thanks again,

Dave L

[stuart noble]

I wouldn't be so sure. Painted bricks give you the worst of both worlds. Not enough of a barrier to prevent rain getting in, but enough to delay it getting back out. Solvent based masonry paints are more effective than water based.

Difficult to tell the difference because the lower part of the wall is usually the wettest, whatever the source.

If you're going that route, I'd put plastic sheet between the wall and the battens, and leave a small gap top and bottom to allow air up behind the plasterboard. Probably not a permanent fix though.

[coherers]

Hmmmmm...... If you deliberately conceal defects (as opposed to just failing to mention them) , this could have unexpected consequences when discovered by the new owner.

[Scott]

And how would they prove that he did it and not the previous bloke?

[Cicero]

=============== This is quite possibly the source of your problem. When pavements are refurbished they tend to gain some height and yours could have grown by several inches over the years.

Try to trace the brick courses from the problem wall around the house to a 'good' wall at the side or rear of your house. Compare the height of the ground at the side or rear with the height of the pavement on the problem side. If there's an obvious discrepancy you *might* have the source of the problem and you *might* have a legitimate claim against the Council.

Also check to see if the pavement drains correctly - away from your house.

Cic.

[BigWallop]

Because it should be apparent to the existing owner who sold the house. And who didn't mention it when it was being sold by them. Damp doesn't lie in waiting for you to sell the house. :-))

[Brad Jeavons]

What consequences, exactly? Isn't it down to the buyer and his surveyor (if any) to detect faults. Surely, the responsibility is on the buyer and his agents rather than the seller, no? There is no law requiring a seller to disclose everything that might be construed as an undesirable feature of the property, is there?

BJ

[John Rumm]

the date printed on the plasterboard?

[Scott]

Sounds like a plan Dave...

A friend of mine managed to get what was essentially tin foil wall paper and you glue it on with a nasty acrylic type glue then wallpaper over. He is still living there and I think it has solved* the problem.

I noticed a very similar material on an outside wall in this place - looks like it has been removed though

*well stopped the damp coming into his flat, probably pushed it onto someone else though obviously not solved it at all.

[BigWallop]

"There is no law

Yes, there is.

[Scott]

But it is rarely enforced. I would be more expecting the surveyor to pick it up. We have a dry lined wall here. The surveyor when we bought didn't spot it, now I'm selling it it was spotted.

I was told that it is due to the wall being north facing and cold and hence suffered condensation. Now that could be true, but then again how do I know? The room always smelt musy until I opened up the fireplace - it is now ok.

Having just sold the sellers disclosure's forms they are pretty limited in the depth of what they ask.

[Scott]

Now that would be funny

[coherers]

Yup. And any "fix" like this will quickly deteriorate ( I know - I have tried to cover up a similar damp problem). So if it looked spanking new when they bought it but is mouldy within six months they can be pretty sure that the previous owner tarted it up.

[Owain]

"Scott" wrote | A friend of mine managed to get what was essentially tin foil | wall paper and you glue it on with a nasty acrylic type glue | then wallpaper over.

Metallic foil wall paper would solve the problem anyway, as it would completely invalidate any readings of dampness by a meter.

Mind you, might knock more off the house value on taste grounds than the damp would.

Owain

[coherers]

Unfortunately, the average muppet using a Protimeter would assume the readings indicated a damp level of 100000% MC and decide the house was actually under water.