Damp patches on newly plastered wall (Ed.)

[Annabelannabel]

Hi,
I live in a mid terraced house. I have had this wall skimmed and painted recently. These damp patches are showing up in the middle of the walls. Does anybody have a clue what they might be. This wall is the living room wall (ground floor) adjoining to the next house. Thanks

 

[JohnD]

How long ago was the wall plastered? Did it dry out to pale pink?

Is there a source of damp in the room, such as wet washing on radiators?

What was on the wall before? Cupboard, fireplace?

Is there a kitchen or bathroom on the neighbours side of the wall?

 

[Annabelannabel]

It was plastered about 3 months ago and was all dry except a couple of areas that appeared discoloured/ slightly darker than the rest but felt dry to the touch. I don’t dry clothes in the room , however the room is directly onto the kitchen (galley kitchen). There was nothing on the wall before- fireplace is on the opposite wall of the room. Not sure what is on my neighbours side- possibly a fireplace

 

[JohnD]

Have a look at the roof to see if there is a chimney above (or on the ridge at the party wall)

To check if it is condensation, tape a piece of clear plastic or clingfilm tightly to the wall, see if water droplets or mist form on the room side of the plastic (condensation) or the wall side (wet wall).

Thicker patches of plaster take longer to dry, for example if there was a defect the plasterer had to fill in.

Ventilate the room well, and photograph the patches in a few weeks to see if they change size.

 

[Annabelannabel]

I believe there is a chimney above- belonging to my neighbour. Great tip regarding the cling film , I will do that I have had air bricks installed which should help ventilation. Anything else I can do to help ventilation ? Thankyou

 

[JohnD]

If you have trickle vents, leave them open.

If you have a kitchen extractor, run it during cooking or washing up.

Another source is leaking pipes or drains, usually in or near the kitchen or bathroom, including under the floor, but can be radiator pipes. Look for any damp patches on the external brickwork, near the ground or under leaking or blocked gutters and downpipes.

Old chimneys can be damp if they are blocked and have no ventilation.

Water vapour is lighter than air and rises through the house.

Look out for misty windows on cold mornings.

Bedrooms benefit from opening the windows in the morning after throwing back the bedclothes.