Moist wood is the perfect breeding ground for fungi. As the fungi grow deep in the damaged wood, the tiny spores eat away at the wood and create new spores in the process. The result is wood that is cracked, porous, and unstable. This is known as dry rot.

Steps to Dry Rot Repair

If the dry rot is found in a weight-bearing area, the wood should be torn out and completely replaced. However, dry rot repair can be done in place for areas like baseboards, window frames, and trim. Here’s how:

1. Eliminate the source of moisture. There’s no point in repairing an area that will be damaged again. Find the source of the moisture and eliminate it before you proceed.
2. Dig it out. Remove as much of the dry rot area as you can, and undercut the area so the filler you use will stay in place.
3. Prep the surface. Drill shallow holes around the margin of the wood, creating tiny “cups” that will hold liquid. Then fill the holes with a “wood hardener” liquid that protects the surface and gives the filler something to hold onto. You can choose a one-step treatment or an epoxy blend. If you have trouble getting the liquid into the little cups you drilled, use a turkey baster.
4. Fill it up. Choose a high-quality wood filler and carefully mold it to the area, pressing it into place. If the dry rot area is large, cut a piece of wood a bit smaller than the area, embed it in the filler, and nail it in. Fill the space around it with putty until the area looks as it did originally. The putty allows the wood to expand and shrink naturally without forming cracks in the repaired area.
5. Sand it. After the filler has had time to cure, sand it smooth. Sand the surrounding wood, as well, to create a smooth, elegant line.
6. Prime and Paint. Use a high-quality primer and allow it to dry before brushing on the paint. More than one coat might be necessary to make the area look uniform.

When to Call a Professional

If you have a wide area of dry rot or feel uncomfortable with dry rot repair, stay on the safe side and call a contractor to handle the job for you. If the dry rot is in a weight-bearing area of your home, calling a professional will give you the peace of mind of knowing the job is done, and done well.

About the author: Shannon Dauphin is a freelance writer based near Nashville, Tennessee. Her house was built in 1901, so home repair and renovation have become her hobbies.