Damp Ceiling

Cotta

Hi All,

I have a slightly damp ceiling along the legth of the wall within a second floor bedroom just above the window. Is this cause for concern or could it be as simple as the gutters needing cleaned?

SailorSam

Do the gutters look as if they need clearing ?
When it's raining can you see them overflowing.
If you can't get up a ladder yourself, the cheapest way is ask the window cleaner to take a look.

Cotta

They don't seem to be overflowing with water.

WestonDave

Could be that the lintel over the window is bridging cold across which is causing condensation on the inside. You can run a simple test for this. Dry the surface as best you can - paper towel, hair dryer etc. Stick a piece of foil on the affected area so its properly in contact with the wall all over. After a night, take it off and check it. Wet on the wall side means damp coming through the wall, wet on the room side means condensation on a cold surface.

Cotta

It seems to be an issue with condensation.

WestonDave

Ok - that's not so unexpected. When the loft is insulated the insulation shouldn't be pushed right to the edge otherwise you create air circulation issues in the loft. However the downside to that is that you can end up with a cold strip along the wall which being colder attracts condensation. Long term if not resolved you will get mould growth here.


What you do about it depends on whether you are getting condensation issues elsewhere as well (e.g. on windows etc). If you are then you need to reduce humidity levels by either changing air more often (ventilation) or dehumidifying (run a dehumidifier). If the house in general is OK and its just that one spot, then have a look in the loft to see if the insulation is in the right places (needs to be as far in to the eaves as it can go whilst still allowing space over the top for air to move). Maybe something as simple as a layer of that silver bubble insulation on the bits of the loft floor that the insulation can't get into might be enough to stop it being quite so cold. If all else fails I'd give the ceiling a coat of a paint with a mould killer in it. (Zinsser Perma White is one I've used with good results).


In general you should always try to cure the underlying problem but sometimes you do end up with a stubborn patch which persists due to the structure of the house and can't be cured without something drastic like drylining. In those cases a bit of symptom relief like anti mould paint is all you can do. (Our previous house had concrete trough gutters that bridged the cavity so we had a cold strip at the top of the walls - worst in the north facing rooms of which the bathroom was one. Short of drylining we could only deal with the mould that resulted).

Cotta

The house is new to me and I know the loft hasn't been insulated. A plumber was around recently to perform some basic checks and he advised of this and the fact that there are grants available for this.