Got "Ugly" Window Sills? Stained from Moisture?

The PW Asks: What can you do when the wood under your window gets gray or blackish?

The Painter Says:

Condensation occurs in the winter from the glass sweating and then freezing on the window sash and jamb. It then breaks down and lifts the finish, causing wood to mold and deteriorate.

Remedy: We remove the old deteriorated finish from the window and the sash and where the moisture has begun to lift the finish. We apply wood bleach if it has turned black from mold or mildew. Then we apply a light stain to blend with the existing finish and a couple of coats of an oil polyurethane brushed up a little onto the glass to bond with the glass so that moisture can’t penetrate from the back side of the window sash again, and rot the bottom of the window.

This is not a do-it-yourself task, it requires a skilled craftsman.

PW: Have you had “Ugly” Window Success?

Painter: Very good! Very good success. We help people catch the window sash rotting situation before they go bad and the finish is peeling and the wood is graying. Maintaining the bottoms of windows gives people more longevity out of the windows rather than replacing them.

PW: Do a lot of people replace their windows from not catching the situation in time?

Painter:  Replacing happens a lot so it is worth having them protected.


PW: Besides the condensation on the glass, are there other issues involved with decaying window sash?


Painter: Yes. The windows were probably sprayed with a cellulose lacquer. Think of a sponge. That is the chemical make-up of a cellulose lacquer which is very common on the market to be used in new construction because it is cheap. We always use a vinyl undercoat and a post-catalyzed lacquer. It costs more and makes all the difference. The new construction homes finished by Signet Painting over the past twenty years do not have this "ugly" stained window sash problem.