The Rot Doctor


Subject: window sill rot question again
Date: Tue, 01 May 2001

Hey doc. Sorry but I have to tackle these projects one at a time due to my weird work schedule and the weather. I recently received my order and repaired the fascia boards as per your advice. They turned out great, thanks.

It appears I have several window sill problems, but I will address just this one today, and the others later as I need to order more product. The 2nd story windowsill (aren't I lucky) is the problem today. At the right hand corner I have a large hole and a lot of rot, even extending down below the bottom of the sill(hidden by paint but very soft to probing). Anyway, the hole is about as big as an elongated silver dollar and extends through the vertical trim piece on the right hand side of the window. It has completely penetrated into the window weight cavity it appears, as I can see the inside wall boards, between two studs. The hole extends upward a couple of inches, and also to the right of the trim piece where there is a smaller hole. So how can I avoid filling in the space between the 2 x 4's (back it somehow?) so I don't have to use so much epoxy filler. Or should I also use the "lay-up and laminate?" stuff. Any suggestions would be greatly appreciated. Too bad you couldn't do an "on-line show" kind of like This Old House and use my place as one of your projects to show off your products. Then you could see for yourself exactly what I needed!!!! Thanks again for your time.



Okay, you've given me a pretty good picture of this particular problem. A nice one, huh?

Here's what I'd suggest: When the wood is reasonably dry, saturate it all with CPES. You may want to use a sprayer (such as the spray bottle we sell) to pump the CPES into the cavity. You'll want to allow it to saturate the wood, and run down into affected areas you can't see. Basically what happens here is the CPES runs where the water ran, and where it meets soft or deteriorated wood it saturates it and hardens it and effectively stops the rotting process.

After waiting about 3-4 days (or longer), you should be able to make yourself some bendable "dams" out of something like plastic or cardboard, put a string or piece of wire in the middle and use that to pull the dam against the inside of the area you are repairing. Hold that in place while you push in the Epoxy Filler. The "dam" will serve as a backing surface to keep the Epoxy Filler from dropping down between the studs. After 24 hours the Epoxy Filler will have hardened and you can snip off the string or wire and have yourself a good, solid repair. The Epoxy Filler can be sanded smooth and repainted.

My guess is you'll probably need close to a 2-quart unit of the CPES to thoroughly saturate the area, and have enough to run down into unseen areas. As for the Epoxy Filler, it's strictly a volume issue -- as much as you need to fill the void.

One other option here: Sometimes it is possible to use a piece of CPES-treated wood to fill some of the larger areas, using the Epoxy Filler to hold it in place and permanently locate it. Just thought I should mention that.

Come on back when you have additional questions. We'll help any way we can.