Damp on demise wall

[OuluChris]

Hi,

I live in an apartment building constructed in the late 1980's in London.

My bedroom wall is also the demising wall. On the other side is my neighbour's apartment. There are three floors of apartments above me.

Recently a small patch of the wall has been looking damp, growing black mould, and having a "froth" on it.

I guess I will need to contact the building management company but before I do so does anybody have any ideas about what could be happening and how difficult (and costly!) resolution of this problem could be.

Many thanks,


Chris

 

[^woody^]

Black mould is almost always condensation from your side, not damp coming in.

What part of the wall does it relate to, and what could be on the other side or above?

 

[OuluChris]

I'm not sure where the condensation would be coming from on my side.

It's difficult to say what is on the other side and above. My guess is that the other side is an entrance corridor but I have no idea what could be above.


Chris

 

[HawkEye244]

Hi Chris your photo didn't show properly.

 

[John D v2.0]

I'm not sure where the condensation would be coming from on my side.

It's difficult to say what is on the other side and above. My guess is that the other side is an entrance corridor but I have no idea what could be above.


Chris

Condensation comes from humidity in the air hitting a cold surface. If it's an entrance it might be cooler there. You can prove with a hygrometer and an it thermometer.