I have a long-neglected window sill that now has fungus (not mold) growing out of it. We are pretty sure that the wood is not rotten, as the wood feels firm to the touch.

Can I still salvage the sill by scraping away the old paint, killing the fungus, and painting and sealing it? Or is it too late? If it's not too late, what's the best way forward?

Brown fungus growing straight out of window sill

  • The picture seems to imply that the trim is a finger jointed piece that is starting to come apart due to moisture getting into the glue joints.
    – Michael Karas
    Commented Oct 19, 2014 at 16:43

1 Answer 1


The wood may give the impression of feeling firm but could very well be beyond recovery. You should try probing the wood with a narrow pointed tool such a flat blade screwdriver. If you can push the tool into the wood any amount then it is a pretty good indication that this needs replacement.

Replacement of the outside window trim can involve a lot of issues depending upon the type of siding and whether the siding goes under the trim or butts up to the trim. A few more pictures showing the trim installation would help for giving further advice.

Another thing that will need looking into is to see of the compromised wood extends beyond just the trim. Is the sill and/or frame of the window also starting to go bad? If so this could be an indication for replacement of the whole window.

  • 1
    What you see is the fruiting body of fungal mycellium that has penetrated into the wood after it has undergone decomposition. Replacement is the only fix. Painting it is like painting blister rust on a car body, it doesn't stop the rot. As noted, trim removal and further inspection to access how far the rot has gotten into the infrastructure are necessary. Commented Oct 19, 2014 at 17:14
  • @Michael: I can certainly provide more pics, and will try the screwdriver test soon. What kind of pics should I take? Regarding the extent of the damage, how do I determine that?
    – anon
    Commented Oct 20, 2014 at 1:44
  • @FiascoLabs: Yikes. I will try to determine the amount of rot that has occurred.
    – anon
    Commented Oct 20, 2014 at 1:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.