Damp on Bedroom Wall-Cold Bridging?

[Chris009]

Afternoon All,

I have recently bought a house and since the temperatures have dropped I have noticed a damp patch on the wall in the upstairs bedroom at the front of the property. (see Pic)

The bedroom does have moderate condensation on the windows and I have read about cold bridging and wanted some advice as to whether the issue is damp or cold bridging.

I live in a terraced house and there is render on the external wall that appears to be in good condition with no obvious crack to allow moisture in. I think the house had been replastered in 2021 and the same wall in the living room at the front of the house doesn't have any damp spots.

There are no radiators close by for a potential leak and there is no damp on the ceiling indicating a leak in the roof space.

If anybody has had a similar issue and is aware of a fix I would be very grateful. This is my first house and I have been taken by surprise and I'm not sure what to do.

Any help would be greatly appreciated.

Thanks,

Chris

 

[^woody^]

Cold bridging is not a defect.

The diagnosis would be whether its penetrating damp from outside, or condensation damp from inside.

You acknowledge an existing condensation issue and that does appear to be the cause and what needs to be dealt with.

However there is something about that patch and the whole section of wall above it that is making it more susceptible to condensation.

 

[Chris009]

Hi,

Thank you so much for your reply @^woody^

It looks like there may have been a ventilation vent in the wall that has been rendered over.

How can I address this issue in the short term?

Will a dehumidifier make any difference along with keeping the room warm till I can afford to get the vent opened up?

Any guidance would be greatly appreciated.

Thanks,

Chris

 

[^woody^]

If there was a vent there, is it still open on the back?

Either way, that would not explain why all the wall above is darker, and with a straight demarcation line.

Is the plaster either side of that area the same? Sound the same when tapped, feel the same?

What type of house, old with solid walls?
Is that a box room, and that a corner?

 

[Chris009]

Hi,

The walls have been plastered and it appears that the section of wall that is damp seems solid. Next to it to the right is has a slightly more hollow sound.

The house was built in the 1900's and this is the master bedroom at the front.

I'm not sure there will be any insulation in the walls given the age of the building.

Thanks,

Chris

 

[Chris009]

@^woody^ here is a picture of the wall for reference.

 

[^woody^]

Right. Hollow implies dry lined with plasterboard, and hard/dull implies wet plaster - which can be more susceptible to condensation damp. Does the rest of the wall sound hollow?

Is there anything on the external to indicate a problem with the external wall or roof above, or any indication of something being removed such as a chimney?

If no other signs of a problem, then if for some other reason that damp section of wall has been wet plastered and different to the adjacent boarded areas, then if that damp section was replaced with plasterboard the same as the adjacent wall, then that should sort out the condensation damp, leaving you to address any general condensation control.

 

[Chris009]

@^woody^ The rest of the wall sounds solid. There is a small section adjacent to the damp patch that does have a more hollow sound when knocking on it. It looks like in that section of the external wall there may have been a satellite that has been taken down or potentially a vent. The house next door is vacant and there is a crack in the render on the neighboring property but nowhere near that section of wall. See attached picture. I will be ordering a dehumidifier now and would be grateful for any other suggestions to address the issue.

Thanks again!!