How to Fix a Hole in a Rotted Window Frame

Lay plastic sheeting or newspaper on the window ledge beneath the rotted section of the window frame and use masking tape to hold it in place. Cover the floor or ground beneath the window frame with newspaper or sheeting, using masking tape to hold it in place against the wall or siding of the house.

Place the tip of a flathead screwdriver at the edge of the rotted hole in the window frame. Hit the bottom of the flathead screwdriver with a hammer to force the flat tip into the wood at the edge of the rotted section, and pry back to remove the piece of wood that you knocked loose.

Move the flathead screwdriver along the outside edge of the rotted section of window frame and hit the bottom with a hammer again. Pry away the loose piece of wood. Go around the entire area of rotted wood in this manner until you get to solid wood that doesn’t feel soft to the touch.

Pour a bottle of epoxy into a disposable container and add the hardener provided with the epoxy. Mix the epoxy well with a plastic knife and allow the epoxy to sit for the time recommended by the manufacturer to reach the proper consistency. Wipe the knife off with a paper towel to remove the epoxy before it dries.

Spread the epoxy into the hole in the rotted window frame with the plastic knife. Smooth the epoxy down so that it sits evenly with the rest of the window frame. Allow the epoxy to dry for 24 hours.

Sand down the epoxied section of the window frame with medium-grit sandpaper. Apply paint primer to the surface and paint over the epoxy in the same color as the rest of the frame. Let the paint dry 24 hours and apply waterproof sealer over the repaired section of the frame.