The Rot Doctor


Subject: Window Rot?
Date: Sun, 30 Sep 2001

Hello, My family and I have recently moved into a home about 28 years old. All of the windows are storm windows with the sectional part of the panes painted white (sorry I don't know the proper word). The problem is that there is a black looking substance coming thru the paint, which looks like it may be some kind of fungus. The storm windows are no more than 10 years old and are in pretty good condition other than having an unattractive look in certain sections. Is there a simple way to get rid of it other than replacing the windows? Thank you for any help you can give me.

Having window pains

It could be fungus, or it could be a bacterial mildew.

Your repair procedure here is fairly standard. Remove the paint from the affected wood, sand it smooth, and then treat with CPES (Clear Penetrating Epoxy Sealer). This will sterilize the wood, eliminate the fungal/bacterial problem, harden any soft wood, and form a prime coat for repainting. Once this is done -- and it will only have to be done once -- the discoloration will not reappear.

It won't take much CPES to do this. A two quart unit should be enough to do all the windows. Disposable bristle brushes are recommended for application, and lacquer thinner for any clean-up.

Come back if you have additional questions,