I've recently noticed some spots appear on a pitched ceiling of our bedroom, and I'm trying to work out what could be causing them. I've only been in the house 12 months, and didn't notice anything last year, but it means I don't have a lot to compare to.

Here's some photos:

Damp spots on painted ceiling Close up of spot c9cm across More spots

Altogether there are 7 of them, all at exactly the same height up the wall/ceiling. They range in size, the smallest being the size of my thumb to the largest with the photo of the ruler. The distances between them vary too (patches marked with an O):

O -- 65cm -- O -- 32cm -- O               O -- 65cm -- O -- 25cm -- O -- 12cm -- O

I've had my neighbour (and ex-roofer) take a look, and from the outside on a ladder (not on the roof) he couldn't see anything that looked like it could be leaking from the perspective of the tiles. He said they looked in great condition. Additionally throughout heavy rain, this has been fine. It's only since we've hit freezing conditions that I've noticed it.

A small change from last year, is we also had our window replaced (sliding doors) to something less drafty. Could this potentially be a condensation thing? There are no vents etc on the outside of the roof - I've briefly read that vent tiles exist. The temperature of the room varies between 14-19 degrees C throughout the day/night.

Also worth noting that this is in the UK in-case that's relevant to the distances between. Appreciate any advice on what this could be/how I resolve it!

  • 3
    Think it might be condensation, warm house air hitting a cold rafter. Roof leaks is also possible but thinking 60/40 for condensation. Either way someone needs to check it out.
    – crip659
    Commented Dec 18, 2022 at 16:57
  • 2
    It wouldn’t cost much to cut a hole in the plaster/drywall to get an accurate assessment. Try and cut it out in one piece for easy re-use. Commented Dec 18, 2022 at 20:57

1 Answer 1




rat pee

Roof rats like attics. If your roof is sound and not leaking, maybe you have rats up there. It happened to me.

It looks to me like those spots are along a seam of some kind. Maybe that is why they are showing up there and not elsewhere.

I hope it is not rats. Although getting rid of rats and repainting is probably about the same expense as fixing the roof and repainting.

  • I won't rule anything out yet, but given we've never heard anything, and we've got 2 cats who I think would be pawing at the ceiling I'm hoping it's not a rat. I've never actually seen a rat in the area, though the odd mouse has been caught by said cats...
    – Ian
    Commented Dec 18, 2022 at 19:26
  • I did hear something and went up and looked around; nothing. Then when I had the rat guy out, no question. Much poo and signs of long habitation. They nested in the insulation which is how they got away with it. I did not know how to look. Word from the formerly unwise - do not address attic rats by throwing poison into the recesses of the attic. Rats eat the poison and then die. In the walls. Your family members will then be pawing at the walls to escape the smelly house.
    – Willk
    Commented Dec 18, 2022 at 20:58
  • Poison fed to rats all too often also ends up inside non-target animals such as owls, hawks, pets, etc.
    – kreemoweet
    Commented Dec 19, 2022 at 7:33
  • Those look much too regular to be rats, I think. Commented Dec 19, 2022 at 14:41

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