Exterior Window Repair

[Herb Smith]

I've got a couple of old wood storm windows to repair. These are just small basement windows about 32"x25". At the bottom corner on one of them, the wood has rotted - area involved is about 3"x1"x1". This is an old house (circa 1920). Years ago I seem to remember using an epoxy-type product to replace a small section of a rotted window sill, but memory fails me as to what I used and products have probably improved since then anyway. I guess I could just cut back the area to good wood and then just replace that area with new wood. Is there a better way?

[Paul Girouard]

There is all ways another way!

#1: You could remake the entire sash , apply CPES to the raw wood , then prime , re-glaze , repaint.


#2: Remake just the rotten part using epoxy:




























#3: Just fill with epoxy , and sand fair after it drys:

[Paul F Franklin]

I like WoodEpox for exterior wood repairs. It's a two part knead-able epoxy filler. You knead together equal parts of A and B and it forms a thick putty a little stiffer than play dough. You over apply it, let it set, and then machine or sand it to desired shape. It is not real sticky and sometimes seems like it won't stay put, but it really does. A surform rasp does an excellent job of quickly shaping it. It's best to shape it within a day of applying it; it continues to get harder for a few days. Once set, it paints very well and has held up very well outdoors everywhere I've used it.

[Tom Ewell]

Abatron is what I use, probably similar enough to other products ... two part kneading 'dough' just like Paul mentions
I keep several handy sized pieces of laminate (putty knife size) using alcohol to 'sweat' the laminate while shaping the epoxy filler to a smooth finish.
Once set, shape like wood.

Structural repairs should be made where needed. Think of this stuff as formable body filler and not structural substitution.

Abatron also has the resin repair systems to mitigate rot, there's a bunch of similar system available.

[Lee Schierer]

I've used Minwax Wood Hardner and Minwax two part wood filler for wood repairs such as you are facing.

[lowell holmes]

I had rotten window sills. I replaced the wood with treated lumber and painted. The repair has lasted 20 years and is still sound.

You know quarter sawn white oak is a very good wood for moisture resistance. You fix it and it stays fixed.

[Stan Calow]

I use Elmer's Pro-bond after Min Wax wood hardener.

[Jeff Bartley]

Herb-
Post up pics of your rotten storms and it'll be easier to advise on a repair. Sometimes it's best to do a surgical wood repair, sometimes epoxy works better.
I believe it's Abatron who makes an epoxy product called Rot Consolidate, it's a thin two-part mix brushed onto rot. It then hardens after absorbing into the wood. This is followed by the aforementioned WoodEpox, the two-part play dough like epoxy. WoodEpox is a structural product but it needs something to 'tooth' into in order to provide a solid repair.
We do a lot of these repairs at work!

[Rich Riddle]

We started doing this on the back of our house with enormous windows and found that even though the wood around the rotted part wasn't rotted, it wasn't the strongest either. We then replaced the wood with treated wood and composite wood where possible. It took a month to repair, but it's held up for a few years. Good luck.

[Ellen Benkin]

Bondo -- it works

[lowell holmes]

Bondo -- it works

There are some window issues that cannot be fixed with Bondo.
I had three 48" wide picture windows with plate glass in them that had rot on the bottom rails. The window frames were mulled together.
New wood was the only solution. The wood that I put in will not rot because it is flashed properly and in some cases the exterior wood is quarter sawn white oak.

If you are nor familiar with the fact that quarter sawn white oak is one of the water resistant woods, you need to look it up.

[Herb Smith]

Thanks for all the help. I'll be using the Abatron product for my small repair.

Yes, I knew about QS White Oak as being water resistant, but in this case it's probably overkill. I'm also making a couple of new storms for these small basement windows and will be using cypress. Cypress has served me well for almost 20 screens and more than a few storm windows on the main floor of the house. Water resistant, seems to hold up well in our rather severe winter climate and a couple of bucks less expensive per bd. ft. compared with QS White Oak.