It Damp Possible On An Interior Wall?

[silliemillie]

On part of the wall between my kitchen & downstairs loo the paint keeps bubbling up and going white & brown.

Its an inside wall now but used to be an outside wall (extension was attached here) so at first I thought maybe rain was getting in somehow from the roof. The roof & flashing has been replaced a few months now & I am still getting it even after I have rubbed it all off it returns.

My son thinks it maybe damp but I am not so sure especially in this weather, I am thinking maybe an interior pipe is leaking?

I really don't know who to contact. If I get a damp man round & its a pipe then I am wasting my money (& don't have a lot to waste!)

I really want to get it sorted but don't know which road to go down.

Any advice would be appreciated.

[boxtops]

Is the bubbling from ground level?

[Old_Geezer]

Of course it is possible. Especially if water pipes are nearby as there would be between a kitchen and toilet. Or maybe a leak from a bathroom above. I'd have thought it less likely one has bridged the dampcourse from the base below, but I guess it is possible. Or it may be condensation issues. And of course, as you say it could be the roof leaking maybe.

How long has it been an inside wall ? I'm making guesses but could it be the wall was damp and has yet to dry out ? Is there problem with the plaster underneath ?

One hint might be where the stain occurs. High, low, middle of the wall ?

Some things ought to be checkable for yourself. Check nearby pipes, look for drips or pools of water.

You may find a damp engineer would make a free inspection in the hope of finding something, that may be worth considering. I know when I had evidence of damp in my loft I got a roofer out who didn't charge to say it wasn't a roof problem, thus pointing the suspicion on the pipework.

[The Builder]

Which side of the wall is affected, Millie. Is it the original interior or exterior side?
Roughly how old is the house?
Single story extension?
Flat roof?

[silliemillie]

Thanks for all your replies,

the house is 1920's but the extension is about 15 years old, the flat roof was replaced about 4 months ago but it was happening before & now after then (I thought the new roof would sort it out)

Most of it is at ground level up but there are a few small patches on the extension side further up.

Its a single story flat roof.

[The Builder]

So, a 2-storey house with a single storey extension?
1920s, so probably a cavity wall?
Does the extension face the weather (West)?

One possibility... when a single storey extension is put on a house, the outer leaf of the cavity wall becomes the interior wall of the extension.
Outer leaves are intended to take the weather. They get soaked (quite normal).
You can see that the old outer wall above the extension becomes wet, and this descends into the room below.

Does that fit?

[silliemillie]

Thanks builder, that sounds possible doesn't it.

I think the original house is stone so don't think there is a cavity but there probably is where the extension meets it, do you think that's possible?

So whats the best thing to do, do you think? I just want to be able to call the right person if you know what I mean.

Wish you lived near me! LOL!

[The Builder]

Yes, Millie, I wish I could come and have a look for myself :o)

Stone, yes, it could be solid wall construction. Not so likely in the 20s. It rather depends on the "poshness" of the house. Dressed stone was used a lot around then. That is, it's cut into precise shapes, but with a standard thickness, so that it can be used with a cavity.

You couldn't put up a close-up pic of the stone could you?

Either way... if a cavity, then these should have been installed at the time of constructing the extension. ........

http://www.screwfix.com/p/refurbishment-cavity-tray-133-x-450mm/54472

The trouble is, it's "dead" money. You can't see it, so some builders leave it out to keep costs down. It's totally unforgivable really, but all too common.

The picture shows the refurbishment type that should be put in now....... if it's a cavity wall.

For a solid wall, a horizontal chase (groove) is cut into the stone, and a lead flashing slotted in........ the deeper, the better. The cut is made about 150mm above the roof level. The lead then drapes down over the felt. (I'm assuming here that it's a flat roof. No matter, for a slopey roof, the same thing applies, but with slopey lead flashings.

[The Builder]

That's a lot to take in Millie, and I may be barking up the wrong tree entirely.

For now, let's assume the flashing was put in properly when you had the roof re-covered.

Prior to that, years of water seepage from the roof has soaked the wall in question. In good weather, the dry air will draw moisture out of the wall, onto the surface. This is what you have now. Vinyl emulsions in kitchens make the matter worse by not letting the moisture out... so it forces the paint off.

I'd be inclined to take that area of plaster off the wall for a good look, then re-plastering with something more breathable. Drastic, but cheaper than roofwork, especially if not needed!

So many possibilities. The only answer is to have someone you can trust look at it. Easier said than done though.

[silliemillie]

I will have to bite the bullet & call someone in, I know I should but keep putting it off scared of what they might find & or being ripped off.

But I really appreciate all your advice, there are quite a few pointers to be going on with.