Damp or condensation? :?

[k8palmer]

First of all this is my first post on here so hello to all.

I live in a 1940s/50s semi-detatched former council house. Just yesterday I noticed a damp patch and some spots of black mould in a bottom corner of our dining room - I only noticed because I was moving some books that were on the floor against the wall, and noticed that a couple of the books also had a couple of spots of mould on them and smelt damp, but I don't know how long it's been like this. The corner is formed of 2 outside walls and is SE facing. with the South wall forming the gable end - this wall is shelved in the dining room and used for storing more books etc.

Rising damp seems unlikely, as due to the slope the house is built on the floor is elevated at least a meter above ground level at this side of the house, but could this still be possible? There is a drainage pipe near the corner on the East side but I've seen no evidence of this leaking. The guttering was cleaned out a few months ago. I have no idea if there has ever been any damp proofing to the property although the previous owners have put in wall cavity insulation (you can see the marks on the outside walls where this was done).

We do often use this room for drying clothes (particularly in colder/wetter weather when it's impossible to hang them outside - we don't have a tumble drier) which is why I suspected condensation - particularly as the corner is furthest from the radiator. It's not a room we use much and has been used as a bit of a dumping ground when decorating other rooms. There is what I suspect is an air vent higher up the South wall between 2 of the shelves - a raised rectangular shape about 12 inches across, that the previous owners have papered over! Should I uncover this, and is condensation the most likely cause? If so would a dehumidifier help?

Any advice gratefully received ... thanks

Kate

 

[JohnD]

tape a piece of clear plastic tightly to the wall. If water forms on the room side it is condenation. If it forms on the wall side it is from the wall.

Moisture forming on external walls behind furniture is typoxal of condensation. Opening the window, or the airbrick, to ventilate the room better will often cure it.

Does anyone drape wet washing around the house or over radiators?

Post some pics if you can //www.diynot.com/forums/viewtopic.php?t=129539

 

[k8palmer]

Thanks for your reply.

We do hang washing to dry in this room on an indoor drying rack / clothes horse when it is too cold or wet to hang it outside (which is quite often as we live in Scotland! )

I have been guilty of drying damp towels over radiators too.... and hanging sheets to dry over doors, bannisters etc as there's nowhere else to put them... we do open the window in there when we can, but I'm also thinking of uncovering the air vent, I'd need to rip off the wallpaper though.
I'm going to try to upload a photo...

View media item 52014

 

[foxhole]

You should not block any vents, they are there to prevent damp and condensation and where gas appliances are present to supply air to avoid poisonous fumes.

 

[k8palmer]

Thanks. I did not block the vent (if that's what it is) myself - it was papered over when I moved in. What's the best way to uncover it without making too much mess? Stanley knife?

 

[foxhole]

Should be fine.