I have a vinyl window in my shower sitting on top of a marble or stone sill. The silicone caulking didn't stick properly last time and is now peeling off and getting moldy, since it's always getting wet.

Is there a different caulking I should use in this situation? Or is there something else entirely that I should do to seal it?

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    Silicone will not stick to a surface that has silicone Residue on it. All traces of the old caulk must be removed.
    – Kris
    Commented Jul 12, 2021 at 12:43
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    There should be some slope from the window frame to the wall to help the water run off. It appears that some may be sitting there. No matter what you do, it'll get nasty if the water just puddles. Other than thoroughly clean & recaulk, your only option may be to ensure that the ledge is well dried after each shower & make sure the vent fan runs until the walls are dry.
    – FreeMan
    Commented Jul 12, 2021 at 13:47
  • Thanks for the tips. The ledge is sloped, it may be that the last time I didn't get all of the existing caulk off. It may be that the caulk will never adhere very well to the polished marble, but I'll give it another try and make sure I clean it really well first.
    – Billiam
    Commented Jul 20, 2021 at 14:03

1 Answer 1


Be sure to use a "kitchen and bath" silicone caulk which is mold-resistant. Other caulks (e.g., for windows and doors) will not do as well in the wet/humid environment.

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