We have a room that has been unused for a while. We noticed some faint spots appearing on the ceiling a couple years ago. The spots have slightly darkened over time but haven't changed in size or shape. I was not sure if it was mold or something else. We couldn't see any obvious signs of water damage or moisture in that area. We even looked in the attic. Other than these spots isolated in one corner, the ceiling and other walls look fine. We ignored it for all these years as the spots haven't really changed in size, shape or color but now we want to use the room and were planning on painting it when we noticed these spots again. Could this be mold? If so, is it dangerous or we can just put a good primer and paint it over?

Update: The mystery was solved. The part of the ceiling where these mysterious spots appeared were beyond the accessible space of the attic. Turns out it was squirrels. They were nesting in that location. The attic narrowed to zero but beyond that it had a cavity that was accessible from outside the roof. This cavity was not properly sealed and the squirrel(s) gained access to the cavity. They were nesting and probably peed on the drywall which explained the spots and smell.

Ceiling picture without flash: Ceiling picture without flash

Ceiling picture with flash: Ceiling picture with flash

4 Answers 4


They definitely look like water spots or leaks. You stated you've been in the attic and saw no sign of leaks... have you been up there lately and actually looked at the drywall where the spots are? If no signs of any leaks, blotch some bleach over the spot. If it's an old water stain that might remove it. If you do paint, get a stain blocker and apply it per instructions before painting. It really does not look like mold. Have you ever had any rodents up in the attic??

  • Yes, the previous owner did have rodents in the attic which were taken care of. Are you thinking this is rat pee or something? It might explain the weird smell in the room.
    – Null
    Dec 19, 2019 at 1:40
  • 2
    @Null That's exactly what was thinking.
    – JACK
    Dec 19, 2019 at 1:47

Looks like a leak in the roof or plumbing above! Find out what is going on before the Sheetrock comes down!

  • Thanks for your answer. However, wouldn't water damage spread over time? It has been like this literally for over two years without any change in the surface area. Also, is this mold?
    – Null
    Dec 19, 2019 at 1:09
  • I gave jack a + but this looks like leaks to me. Water leaks make the spots , molds and fungi usually have color, black if mold ,,, even with a high res photo we cannot tell if it is bad or not!!!!!!!!!!!!
    – Ed Beal
    Dec 19, 2019 at 1:27
  • That's what iI first thought too, but the OP said it hadn't changed in years... maybe a leak that was fixed...+
    – JACK
    Dec 19, 2019 at 13:47

It's difficult to look at a picture to determine if dark spots on a ceiling are mold. Here are a couple links that may help you make the determination:




They look like water stains. Is this along the outside wall ? If so, probably caused by ice damming in the past if you are in an area susceptible to freezing. Now that you are monitoring them, watch out for further wetness. Don't worry though, once dry, prime and paint. Mold starts with dark spots on areas that stay moist.

  • Thanks, I should've mentioned that this home is in a region that receive little rainfall and no snow.
    – Null
    Dec 23, 2019 at 19:44

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