How to Repair a Sticking Sash Window

Sticking may be caused by excess paint, swollen timber, distorted beads or faulty balancing gear.

Diagnose before planing

Observe where resistance occurs during movement and inspect visible edges. Removing historic timber before identifying the cause can make draughts and rattles worse.

Repair options

Correcting paint buildup, adjusting beads, resolving moisture and servicing pulleys may restore movement without replacing the sash.

Common reasons for sticking

Excess paint, swollen timber, displaced beads, loose joints and damaged cords can all cause a sash to bind. The location of resistance helps distinguish them.

Observe the movement

Does the sash jam at the same height every time, or only after wet weather? Does one side rise before the other? Record these clues before attempting any adjustment.

Check moisture first

Dampness can swell timber and signal failed external joints or coatings. Planing timber without fixing moisture may leave a loose, draughty window once it dries.

Repair choices

A repairer may remove paint buildup, reset or renew beads, service the balancing mechanism or carry out localised timber repairs. The aim is a smooth fit with appropriate running clearance.

What to avoid

Do not force a stuck sash or lever against glazing bars. If the glass is cracked or the sash feels unstable, stop and seek help.