Damp appearing on internal wall

[gee3po]

Hi,

We are complete novices at house stuff so learning as we go.

Randomly a damp patch has appeared from on an internal wall. From the bottom upwards. Also some bulging plaster from where there has been previous fittings. The other side of wall is a conservatory. Wall doesn't feel wet anywhere. House is 1920s. We've lived in it about 4 years There is no radiator on this wall. Any ideas? Also how to stop it/fix it? Photos attached. Thanks in advance for any advice that can be given

 

[Jurassicspark]

Is the glass wet? Or does it get wet?

If yes, then it's condensation forming on the cold spots of the wall.

 

[JohnD]

Show us the other side of the wall

Especially the joint where the conservatory roof should be sealed to the wall to keep rain out. Above and below the roof.

What is above this room, on or near the wall?

 

[gee3po]

Thanks for the replies. Glass doesn't get wet. However will keep my eye on that. Here are the photos of the other side. The conservatory does get very cold. There is a bedroom above this room . However there is no damp higher up on this wall. Only lower down. Thanks again

 

[JohnD]

I can't see any trace of rain getting in, but have a look at the outside wall and the flashing. Tap on the plaster in the conservatory to see if it is hollow plasterboard with a gap behind. If so, water or damp may be concealed in the gap. Is there any damp in the conservatory? Look high and low.

To verify condensation, tape a piece of clear plastic or clingfilm to the surface.

If if it condensation, it will form on the surface of the plastic, in the room.

If it is penetrating it will form under the plastic.

 

[Ivor Windybottom]

Top advice above. We have a similar one, the issue is that the flashing wasn't ever cut into the original wall, it's just stuck on flat. If torrential rain is blown in exactly the right direction it runs down the wall from above and behind the flashing. In our case it's a bare stone wall inside the conservatory and it looks a right mess from the one time it leaked during exceptional rain once. In your case it will be running down the inside of the plasterboard and collecting where it does, probably around the plaster, fixings or insulation for the reveal.

Do you see a correlation between the wetness and heavy rain?

If so then the flashing needs replacing. Properly, by cutting it into the wall. Something that conservatory suppliers don't seem to bother doing.

 

[gee3po]

Thank you very much for all the advice. If it was coming in because of poorly fitting flashing would we not see dampness at the top also? We've lived in the house for about 4 years, had a lot of heavy rain and it's only appeared very recently. There is no damp in the conservatory itself. Thanks again

 

[Ivor Windybottom]

The original outside wall of the house will be behind the plasterboard. It's possible that it's running down that wall and not contacting the plasterboard, until it gets to somewhere it can't run any further, e.g. where the door frame is bolted in.

The plasterboard is probably sitting on scattered lumps of adhesive, with an air gap behind most of it. If you tap with your knuckle you'll hear it's hollow and possibly find that odd solid bit where it's supported.

This is all just a possible theory. But if it's related to the rain then it's likely to be along the right lines.

 

[Ivor Windybottom]

Can you see the flashing, e.g. from an upstairs window? If so please take some photos of it.