Damp

[MutleyDoSomething]

Hi.

The back wall in my bedroom wardrobe used to be an external wall before an extension was added. We keep getting damp up the wall close to where it meets the side wall of the house. I put in a tube heater on a thermostat which has helped. I noticed the other day that there are crystals forming on the end of the heater. The house has blown fibre cavity wall insulation but I suspect this wall doesn't have any. It's a loft converted bungalow and the top of this wall is open to air from the eaves so does get cold in winter. My plan was to drill a series of holes and pump it full of expanding foam. However the presence of crystals forming suggest that this may be more than 1 problem. Help and advice would be greatly appreciated, thanks.

 

[MutleyDoSomething]

I should add that a friend checked it a couple of years ago who is in the building game said it was condensation from a cold spot on the wall, but would we get crystals forming from condensation?

 

[Burnerman]

The crystals aren't mould spores by any chance?
Anyway, I wouldn't be injecting the cavity with expanding foam, but I would consider lining the wall on the inside.....assuming there's no penetrating damp of course.
John

 

[^woody^]

Are these Swarovski crystals or white powder?

You say they are on the heater? Are they really, or on the wall?

Ventilation might be more beneficial, but as the man with the burner says, line the wall not inject it. You will never completely fill any cavity with injection foam.

 

[MutleyDoSomething]

Definitely crystals. The end of the heater was touching the skirting board. The wall has previously been covered in white powder with I have washed down with bleach. I am guessing these are mould spores.

 

[^woody^]

Without seeing it is hard to be precise, but normally, white powder on plaster walls is salt leeching out of the wall as moisture evaporates. This might be a sign of more penetrating damp than condensation, or extreme condensation.

Mould will be black, and you tend not to get the two together as white salts is moisture coming out the wall and mould is from fresher moisture on the surface.