Sill - Fixing Rotted Window

Most epoxy fillers come in two parts (resin + hardener). Mix only as much as you can use in 5–10 minutes. Press the mixture firmly into the repair area, overfilling slightly to allow for sanding. Shape it roughly with a putty knife.

A rotted window sill is more than just a cosmetic eyesore; it can compromise your home’s structural integrity by allowing water to seep into the walls. Fortunately, if caught early, most rot can be fixed without a full window replacement. fixing rotted window sill

Brush or spray wood hardener onto the exposed area. It soaks into remaining fibers and consolidates them. Let it cure per manufacturer instructions (usually 2–4 hours). Most epoxy fillers come in two parts (resin + hardener)

Best for localized rot affecting less than 10% to 15% of the sill. Shape it roughly with a putty knife

Dig out all soft, crumbly wood until you reach solid, sound material. Use a chisel, scraper, or rotary tool with a carving bit. The repair area should have clean, sharp edges—no loose fibers.