How to Repair Wood Rot

What You'll Need
Wood scraper
Epoxy filler
Sand paper
Reciprocating saw
Replacement frames, windows, flooring, etc.

Learning to repair wood rot is a home improvement task that everyone should learn. Wood rot is a form of decay that impacts wood that is exposed to moisture and to heat. It is most prevalent in hot and humid environments, but temperate climates can also produce ideal conditions for seasonal wood rot. To prevent extensive damage to wood frames, sills and thresholds, it is important to repair wood rot as soon as it is discovered.

Step 1 – Evaluate the Damage 

The first step is to evaluate how much damage has been caused by the wood rot fungus. You will usually be able to spot visual signs of wood rot such as discoloration, flaking, splitting and splintering. As you visually explore the surface damage, you will also want to feel for deeper damage caused by the threads sent out by the fungus into the wood structure. Palpate the wood for sponge or soft areas. Use a screwdriver to poke at the wood to feel out damage and to test the depth of the damage. 

Step 2 – Remove All of the Damage

The best way to repair wood rot is to remove all of the damaged and infected wood. If you caught the infection early, you may only need to remove small sections of a window sill or a door’s threshold. However, if the damage has been evolving over a long period of time, you may need to remove the entire door or window frame as well as floor boards and subflooring.

To remove the damaged areas you can use a crowbar, hammer and chisel to remove smaller pieces, and a reciprocating saw to take out larger pieces of damaged wood. 

Step 3 – Repair and Replace Missing Wood

Once the damaged wood has been removed, your next step is to repair what is left. Small repairs will include filling in spots with epoxy filler, sanding down the area, and staining and sealing the repaired area so that it matches the look of the rest of the window or door. If a larger piece of wood has been removed then you will need to replace entire pieces of wood. 

If you need to replace a lot of wood that has been damaged, particularly if this damage has occurred around a window or door, it is often easier to simply replace the old door or window with a pre-hung door or window. To do this, you will remove drywall and old wood down to the 2x4-inch studs and fit in the new window or door. This will enable you to attach new insulation, moisture barriers and flashing to help prevent this window or door from being affected by wood rot. 

Step 4 – Maintain Your Wood 

The final step is to maintain your wood to prevent future incidents of wood rot. Maintenance will include seasonal inspections for wood rot and moisture damage and annual applications of sealant and/or stain, depending on the original treatment of the wood. It will also include frequent visual inspections around common places for wood rot, such as around windows, doors and vents.