⏱️ ~2 hours + drying 💰 Cost: ~$30–$50 (vs $500+ for replacement)
To repair a rotted window sill, first using a chisel or scraper until you reach sound, healthy timber. For minor to moderate rot, stabilize the remaining fibers with a liquid wood hardener , then fill the cavity with a two-part epoxy wood filler . If the rot affects more than one-quarter of the sill or is structurally unstable, a full replacement with rot-resistant materials like cedar or PVC is necessary. Preparation and Materials Gather these essential tools before starting: how to repair a rotted window sill