How do I unstick a window that will not open?
Paint, swelling and seized mechanisms — the three causes and the gentle approach to each.
- Difficulty
- beginner
- Time
- 40 min
- Read
- 2 min
- Safety
- caution
Short answer
Usually paint sealing the joint, swelling in humid weather, or a seized hinge. Run a knife round the seam to break the paint seal first — that solves most of them without any force.
A window sticks because something has closed the gap it needs — paint, moisture, or a mechanism that has stopped moving. Force is the wrong response to all three and is what breaks the glass.
Safety
What you'll need
- Craft knife or paint scraper
- Lubricant spray
- Rubber mallet (optional)
- Wooden block (optional)
Step by step
- Work out whether it is paint, swelling or the mechanism.Painted shut: a visible paint film bridging the joint. Swollen: it worked last month and the weather has been wet. Mechanism: the handle moves but the window does not.
- Break the paint seal first.Run a craft knife or a paint scraper along the whole seam between sash and frame, both inside and out where you can reach. This alone frees most painted-shut windows.
- Tap gently around the frame.A rubber mallet, or a hammer against a wooden block, tapping along the sash to break any remaining bond. Gentle and repeated, never one hard blow.
- Apply steady pressure, not sudden force.Push evenly along the sash rather than at one point. Uneven force twists the frame and is what cracks glass.
- Lubricate the mechanism.For a handle that turns without opening, spray the hinges, the locking cams and the friction stays. Work it back and forth. Seized friction hinges are very common.
- Wait for dry weather if it is swelling.Timber swells in humidity. A window that sticks only in wet weather often frees itself when things dry out, and planing it then leaves a gap in summer.
- Plane sparingly, and only when dry.If it genuinely needs easing, mark where it binds, take off very little, and reseal any bare wood immediately or it will absorb moisture and swell again.
- Check the hinges have not dropped.A sash that has dropped on its hinges binds at one corner. Tightening or adjusting the hinges is the fix, not removing wood.
Tips
- Do this in dry weather. A window eased when swollen will rattle when it dries.
- Once free, lubricate the hinges and locking points and repaint the edges properly. Bare timber on a window edge is what causes it to swell next time.
- If it is a fire escape route, a window that will not open is a safety matter rather than an inconvenience.
Questions people ask
How do I open a window that has been painted shut?
Cut along the seam between sash and frame with a craft knife, inside and out, then tap gently around the frame with a mallet. Steady pressure, never a sudden shove.
Why does my window only stick in summer?
Timber swells with humidity. If it works in dry weather, resist planing it — you will have a gap for the rest of the year.