yellowing near crown molding

I live in an older home (built in 1929) in NJ and one of bedrooms has yellowing showing around all the crown molding. The room is below the attic and the attic is insulated above the ceiling. I don’t think it is a water leakage issue. I don’t notice this issue in the other two bedrooms which also have crown molding.

What causes this yellowing? How to I get rid of it and prevent it from coming back?

Thank you for your help!enter image description here

  • When was this room last painted? How about the rest of the rooms? Is this the only room with the yellowing? I'd say that @norcal johnny is right, it's probably caulk, most likely an older/cheaper one to which the fire protection additives are starting to yellow.
    – Chris
    Commented Mar 4, 2019 at 4:41
  • Thank you @norcal Johnny and @Chris! I believe you figured out the mystery and it is the caulk. The stains only appear on or near it. My other bedrooms have mounding too but they appear to be newly installed. I will try to remove as much of the old caulk as possible and then re-caulk and prime with cover stain paint.
    – GOOT
    Commented Mar 6, 2019 at 13:03

1 Answer 1


Most likely, if you are certain it is NOT from moisture it can be the simple fact that it is some inexpensive painters caulk that was never painted.

In a commercial settings ie. eateries, we use clear silicone.

You could simply try painting it.

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