Damp patches from leak or insulation?

eviltimeban

These are on the ceiling of my bedroom, appeared almost overnight. Room is upstairs and there's a converted attic room more or less directly above. No signs of anything amiss in the attic room, and I don't think there are pipes running there as I've never heard them (based on how loud the other pipes in the house are).

Roof leak going under? Bad insulation? Three patches is an odd one, also the fact the two side ones are parallel. Mould appeared on the middle one very quickly.

How do I best assess and what would be the potential fix?

db

That is almost certainly water. The marks are at the screws in the plasterboard. Is there a roof window above this in the attic where rain might have come in?

10-10-20

It's seemingly following the joists and rafters, but I don't think that it has been cold enough yet for condensation run-off from the roof felt, so I think that's out of the question. It could be condensation run-off from a fan vent which has failed though. Or given the windy weather it could be wind-driven rain which got pushed under the slates/tiles.

Can you eye-ball the roof at all?

eviltimeban

https://www.boards.ie/discussion/comment/123943106#Comment_123943106

I think your last point is the one - there's definite gaps under the slates / tiles and that might have caused water to get in. The attic room itself, and the eaves either side, seemed dry when I checked this morning. We have had the issues of birds nesting under the rafters so could be related to that. I've a roofer coming tomorrow to have a look.

If it is that, it's mad the water travelled almost to the centre of the ceiling before making itself known.

On a related point, should I avoid turning on the main light that's in the middle?

10-10-20

As the light is well out of reach then it should be fine to operate unless there is running or pooling water, which you'd know about by now.

whizbang

take down the light; there could be enough of a hole to look through, or even enlarge the hole an the light seems quite big enough