Damp detectives please.

[If in doubt...]

Hi,

When we moved in to this 70's bungalow there was a small patch of damp on the ceiling above a bedroom window. A quick wipe and it went, I then fitted decent extraction in the bathroom and kitchen and it's been fine for 2 years as a spare room.
Now my son and his girlfriend have moved back in temporarily (between renting / buying) and after 4 - 5 months the damp is back with a vengeance and far worse. They spend all their time in there so that's probably half the problem, but it is the only place we get this so before I pop up in the loft to suss things out is there anything in particular I need to be looking for? The loft is insulated so could it be lacking in that area or maybe is there a leak? It runs the whole width of the room above the window and no sign of any leakage that I can see - just seems to be surface damp rather than wet plasterboard.

Thanks in anticipation.

 

[Wayners]

If I had a pound for every time I've seen that.
Bet there is no insulation along that bit so it's a cold plasterboard surface and the warm moist air is dumping water on surface as it's cold.
Windows get condensation?
Then the mould starts growing on the wet surface..
Add insulation above. Will raise dew point.
Don't dry washing in house without dehumidifier running.
Buy a dehumidifier and run every evening for about 4 hours.
After a shower use a hand wet vac to suck up water off tiles and tray/bath.
Lower the moisture in the air you produce and suck the rest up with dehumidifier. Only way I know you will fix that.

 

[^woody^]

The cause is excess humidity, the reason is cold spots causing condesation and the result is mould from lack of air movement.

Check the loft, sort the insulation out.
Check causes of excess humidity from lifestyle.
Fit trickle vents in the window.

Case closed.

 

[If in doubt...]

Thank you chaps. I've always been wary of humidity having come from an old victorian place. Kitchen and bathrooms here will make ear drums bleed with the suction from the extraction I've fitted so I wanted to check if it was something else as there are no other issues elsewhere.

That window is weather facing so possibly colder? I'll also encourage them to go out more often as they practically live in there and it's a small room - Told them the door needs to be left open a bit more also .

I'll get up in the loft and see about the insulation.

Cheers