Spring Window Sealing and Weatherstripping

Walk through your home on a breezy day and check every window. Run your hand along the edges—you can feel drafts as temperature changes. Use the incense test for precise leak detection. Check the caulk around the exterior window frame: cracked, peeling, or missing caulk lets water and air through. Inspect the glazing compound (putty) holding glass in wood windows—it cracks with age. Check for rotted wood on sills. Check the weep holes on vinyl windows (they should be open, not caulked shut). Measure the gap between sash and frame to determine weatherstripping thickness. Note windows that are hard to open or close—they may need track adjustment or new hardware.

Start with stationary gaps: remove old caulk with a putty knife, clean the surface, apply painter's tape for clean lines, and run a bead of silicone or acrylic latex caulk. Smooth with a wet finger or caulk tool. For weatherstripping: clean the window frame where the stripping will adhere. Cut foam tape to length and apply to the top and bottom of the sash where it meets the frame. For sliding windows, apply V-strip to the sides. For casement windows, apply compression strip around the entire opening. Test the window operation—if too tight, reduce thickness slightly. Replace the sash lock if it no longer pulls the window tight against the weatherstripping.

Check for loose or cracked glass panes. For wood windows, replace cracked putty (glazing) by removing old putty, applying primer to the bare wood, pressing in new glazing compound, and painting after it skins over. For vinyl windows, check that the glass is seated in the sash and the rubber gasket is intact. If double-pane windows have condensation inside the glass, the seal has failed and the insulating glass unit needs replacement. For stubborn or sticking windows, clean the tracks and apply silicone lubricant. Adjust sash balances if the window will not stay open. These minor repairs restore functionality and seal performance without full window replacement.

The outside of your window needs attention too. Inspect the caulk bead where the window frame meets the siding—this is the primary water barrier. Remove old caulk and reapply exterior-grade silicone or polyurethane sealant. Check the drip cap above the window—it should direct water away from the top of the frame. If missing or damaged, install a new one from a home center. For basement windows, check for gaps between the window frame and the foundation. Fill large gaps with expanding foam designed for windows and doors, then cover with trim. Exterior sealing prevents water ingress that leads to rot and mold inside walls.