Symptoms
- Vibrating or rattling sound during wind or when a truck passes
- Glass visibly shakes slightly in the frame
- Rattling only from one window, not others nearby
- Worse with the window unlocked
Likely causes
- CommonLoose-fitting sash with worn weatherstrippingAs seals compress over time, they stop cushioning the sash, allowing it to vibrate.
- CommonLock not pulling the sashes together tightlyAn unlocked or worn lock leaves play between the two sash panels.
- PossibleLoose glazing points holding the glass in the sashOlder wood windows use small glazing points that can loosen, letting the glass itself rattle.
- Less commonLoose window frame within the wall openingGaps between the frame and rough opening can let the whole unit shift slightly.
What to do
- Lock the window fully and see if that alone stops the rattle.
- Check weatherstripping along the meeting rail (where the two sashes meet) and replace if compressed or missing.
- For loose glass in an older wood sash, gently press around the glass edge; if it moves, glazing points or putty may need to be added or replaced.
- Add a small strip of adhesive foam weatherstripping at the specific rattling contact point for extra cushioning.
- Check around the exterior trim for gaps between the frame and the wall that could let the whole frame move slightly, and caulk if found.
- For persistent rattling with no clear seal issue, a interior storm window panel can add mass and reduce vibration.
- Re-test during the next windy day to confirm the rattle is resolved.
Tools and parts
- Caulk gun
- Weatherstripping
- Putty knife (if reglazing)
Window glazing pointsSearch: “window glazing points glass”
When to call a pro
Call a window repair pro if the glass itself is loose in an older wood sash and needs reglazing.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.