Off-Colored Rectangular Spots showing through 20 year old painted walls.

Questions & AnswersCategory: Spots and PatchesOff-Colored Rectangular Spots showing through 20 year old painted walls.
C.M. asked 10 years ago

We’ve been living in our house for 10 years now…Have noticed we have off-colored pale tan patches now on the light pastel teal colored painted wall. I don’t think they were there when we moved in, I would have noticed that I’m sure. Now that we’ve moved a bookcase, I notice one behind where it stood as well (on the wall). What could cause this? Is this a paint issue or could it be mold growing behind the wall? My spouse doesn’t think mold as the patches are ‘too rectangular’ (not perfect rectangles, but rectangular in shape) We did remove the carpet as we had what looked like some spots of reddish brown surface mold — which is why I question the spots perhaps being from mold…
Wondering what could be causing these patches: an old paint issue or mold from behind the wall — which is the more likely scenario?

Oh, meant to say that the rectangular patches don’t feel wet in any way…One is on the inside of an exterior wall; the other on a wall adjoining a small bedroom and the bathroom. Just want to supply as many details as possible. Thanks in advance for your reply,

1 Answers
MagicDave answered.

Hard to say, do you have a picture to add? It possibly could be that there were wall pictures hanging there, years ago and the light has caused this difference on shade from the rest of the wall??? I don't thing mold or mildew would be the cause…