Damp Spots

[anahavana]

Hi all,

We've been in our property for about 8 months and about 4 months ago noticed these damp spots on the wall next to our patio doors:

(sorry terrible photo, taken for something else, but it's actually where I noticed the damp spots!)

We have had a damp specialist over and he seems to think it's condensation but I'm not convinced. We have sealed all the pointing directly next to the particular wall to make sure it's not rain coming in from the outside. The wall itself sounds hollow-ish and I think it has plasterboard on it.

We have tried painting over the patched with PVA glue and they disappear for a few days and then work their way through.

Could anyone shed any light on what it might be? I'm not sure if there any pipes worked in behind the wall, but even if there were would a leak make damp spots like these?

Many thanks in advance!

Ana

 

[JohnD]

We have tried painting over the patched with PVA glue

why?

 

[anahavana]

It was something suggested by a few people as the PVA was supposed to form some kind of barrier between the damp and paint, so we could essentially paint over the spots.

 

[JohnD]

no, PVA is water soluble.

That's why it is unsuitable for use under emulsion paint.

 

[anahavana]

AH. Come to think of it I was surprised that so many people mentioned it to me as I remembered using it at primary school and remembered it coming off with water.

Would you be able suggest anything else to seal it? Thanks!

 

[JohnD]

if it really is condensation, it will reduce if you leave the windows open for a week.

you say the wall sounds hollow, what is behind it? Is it an external wall? Could there be pipes behind it?

Is it an extension? I can't see the doors you mention. Stand back and take a wider view please.

 

[RigidRaider]

Does the wall feel cold in places? It could be a cold water pipe behind the paster causing condensation. Or leaking.

 

[anahavana]

It doesn't really feel any colder anywhere else aside from on the actual damp spots...I do wonder if there are pipes in there. Would the only way to find out mean getting someone to rip all the plaster away? Would that mean getting a plumber AND a plasterer in?

 

[JohnD]

please show us a wider picture from the inside, and also the outside of that wall showing where the wet patches are.

it might be pipes, it might be coming in round the top or sides of a door or window frame, it might be a leaking gutter or downpipe, it might be a leaking bath waste upstairs, it might be a radiator pipe.