Damp walls - possibly condensation

[John]

My daughter's house has a built-in wardrobe in a corner of a bedroom. The corner wall is showing signs of mould and damp. I am initially assuming this is due to the fact that the wall is an exposed corner - the house is 1920's and does not have proper cavities.

Next week I will be taking off the remaining wallpaper in the wardrobe and leaving the sliding doors open and have a fan running to try and fix the immediate symptom.

Has anyone any suggestions about ways of lining the wardrobe to minimise the problem?

The house is well pointed - the guttering is new and the roof is good.

[Lobster]

If it's indeed condensation, which does seem likely from your description, then lining the affected area with expanded polystyrene is very effective IME. You can buy it on rolls like wallpaper, about 3mm thick. It works by reducing the temperature gradient between the cold external wall and the moist air inside the house.

You stick in on with special adhesive (all available at B&Q etc).

If you can organise permament ventilation of the wardrobe (eg a grille or two fitted between the room and wardrobe) then so much the better; otherwise tell her to leave the doors open a bit.

David

[The Natural Philosopher]

Yep. Cork tiles are just the ticket for a cold wall.

Paper over if you don't like the look

[The Natural Philosopher]

I would agree with you but for one thing: I do NOT like polystyrene in habitable spaces, because of the toxicity in a fire.

Hence my suggestion to use cork instead.

[Andrew Gabriel]

I would use 25mm thick Cellotex or Kingspan sheets, if you can afford to lose an inch inside the wardrobe. That should guaranee that nearly all the thermal insulation between the room and the outside is behind the surface of the wall, which would make condensation unlikely even if the doors are shut.

[Stuart Noble]

Cork tiles might be more suitable?

[Woland]

corner wall is showing signs of mould and damp. I am initially assuming this is due to the fact that the wall is an exposed corner - the house is 1920's and does not have proper cavities.

leaving the sliding doors open and have a fan running to try and fix the immediate symptom.

John,

as other correspondents have already said, the above is likely to be due to condensation. The killer test would be that of checking the temperature inside the wardrobe w.r.t. the one in the rest of the room: it should be slightly less than in the rest of the room. If this is the case, then the wardrobe is a so-called "cold end" and thus acts as a condensation point for ambient humidity.

My approach would be that of lining the inside with a Kingspan 25mm rigid polyurethane foam board stuck to the wall and covered with ply, which can be easily wallpapered or painted if needed (after the usual priming, etc).

Good luck

W.

[newshound]

You are thinking of polyurethane, not polystyrene. Polystyrene may burn sooty and it's not nice as ceiling tiles because it produces burning rain if you have to go out under it. But I wouldn't worry about 3 mm of polystyrene on a wall, especially under lining paper.