Major damp in corner of room

[mrrusty]

Cold corner behind a cupboard without much air circulation. It'll be condensation. Pull off the rotten plaster, let it dry out and I bet it becomes dry as a bone.

 

[Stotty1]

Cold corner behind a cupboard without much air circulation. It'll be condensation. Pull off the rotten plaster, let it dry out and I bet it becomes dry as a bone.

We are wanting to put a new corner sofa in this corner once decorating is complete.
If it is just condensation will it come back once the sofa is placed there and potentially turn it moldy?

 

[Alastairreid]

Keep it back from the wall to allow air to circulate.

 

[mrrusty]

will it come back once the sofa is placed there and potentially turn it moldy?

Ordinary room air is say 21 degrees and 60% relative humidity. The dew point is surprisingly high - around 12-13 degrees, so if that corner gets cold at night down to the dew point, condensation will form. In the usual way of things as the room air circulates it will evaporate any surface condensation again back in to the air. In unventilated corners, behind wardrobes etc, there is little or no air circulation so any evaporation saturates the air in the local vicinity and evaporation stalls - the condensation stays in the wall and builds up.

The remedy as others have said is make sure there is some air circulation in cold corners.

 

[JohnD]

Tape a piece of clingfilm or clear plastic tightly to the wall.

If it is condensation, it will form on the outer (room side) of the plastic.

If water is coming from the wall, it will form under the plastic

To me, it looks like damp from the leaking drain.

 

[mrrusty]

If water is coming from the wall, it will form under the plastic

..and if the wall is damp from condensation it may also form under the plastic exactly the same.

That test proves nothing because there will be a temperature gradient through the wall - the inside surface may be above the dewpoint and the dewpoint may be part way through the wall between room and cold outside. If condensation at the dew point is inside the wall, you won't necessarily see anything on plastic taped to the surface.

 

[catlad]

Looks like you might be dealing with a solid wall? You would be wise to remove a few tiles so you can access whether or not you can fill it with kingspan or celotex to upgrade it while you are renovating.

 

[JohnD]

..and if the wall is damp from condensation it may also form under the plastic exactly the same.

and how will the the moist air get to the wall through the plastic?

 

[Nige F]

Looks like you might be dealing with a solid wall? You would be wise to remove a few tiles.

then post pictures.

 

[Stotty1]

Looks like you might be dealing with a solid wall? You would be wise to remove a few tiles so you can access whether or not you can fill it with kingspan or celotex to upgrade it while you are renovating.

Good point, Never thought about it being a solid wall, but would explain why the tiles are set further back than the rest of the brickwork.
Filling it with insulation would be great, as it can get cold in this room throughout winter.

I did try prising a few off a while ago but stopped as they were not coming off as easily as I thought they would, I got worried I was going to crack them or cause more damage than I was able to fix at the time.
I will have another go and post pictures of the results.

Thanks

 

[opps]

Good point, Never thought about it being a solid wall, but would explain why the tiles are set further back than the rest of the brickwork.
Filling it with insulation would be great, as it can get cold in this room throughout winter.

I did try prising a few off a while ago but stopped as they were not coming off as easily as I thought they would, I got worried I was going to crack them or cause more damage than I was able to fix at the time.
I will have another go and post pictures of the results.

Thanks

If you take tiles off lower down, how are you going to put them back? The nails are half way up (and under) the tile above.