Repair Wood Dryrot

-When working with old houses, it is not uncommon to come across wood that has dryrotted. The dryrot might appear in window sills, wood siding, window muntins, or even in columns. The difficult choice is whether you should try to repair or go to the expense of replacing the dryrotted element.

-The first issue is safety. If you think the rot may have affected the structural integrity of the house, definitely consider replacement. A structural engineer or architect can take a look at it for you and let you know if it's a safety issue.

-If it is not a structural or safety problem, then you can try to repair the wood dryrot. First, scrape out the ruined, soft rotten wood from the area. Next, apply wood hardener. I've heard of Minwax, but there may be other brands. This will soak into the dry rot wood and give you some kind of base to build upon.

After it has dried (follow manufacturer's recommendations), I would recommend using a product called "Bondo". You can get it at auto parts stores. It is principally used to build up ruined automobile finishes, but remodelers use it to build up wood affected by dryrot. Once again, I would follow the manufacturer's use and safety recommendations, but basically, you apply the bondo to the dryrotted area, let it dry, then sand it down to look as good as possible. Multiple applications may be necessary.

When the dry rot has been repaired with the bondo, you can prime it and paint it at your discretion.

-Note: In my experience, the finished product has looked acceptable, but definitely not excellent. Don't have high expectations for the finished appearance of this technique, but it may be less expensive than replacing the area affected by the wood dry rot.

Good luck!

Former builder and instructor of "Save Time and Money in Home Remodeling" cont. ed. course at Emory University