How To Repair Cracked Window Putty [updated] <2026 Edition>

A well-done putty repair will last 20–30 years. Spend an afternoon on it now, and your windows will thank you for decades.

Repairing cracked window putty (glazing) is a straightforward DIY project that restores both the appearance and the energy efficiency of your windows. While modern sealants exist, traditional glazing putty remains the standard for older wood-framed windows. Putty knife or stiff scraper Replacement glazing putty (oil-based or fast-drying) Heat gun or hair dryer (optional, for stubborn putty) Exterior wood primer and a small brush Fine-grit sandpaper Step-by-Step Repair Guide 1. Remove the Damaged Putty how to repair cracked window putty