A window that will not shut or lock properly is more than a nuisance as the weather turns. It lets in draughts and rain, and it can leave the house less secure than you think. The good news is that the frame is very rarely the problem.
Most faults come down to a handful of parts that can be changed without replacing the window.
How a UPVC window locks
When you turn the handle on a typical UPVC window, it drives a gearbox inside the sash. That moves a bar around the edge of the window with small locking points, often called cams or mushrooms, that slide into keeps on the frame. The window is held on friction hinges at the top and bottom, which let it swing open and stay where you leave it.
If any of those parts wears, bends or moves out of line, the window can stop closing or locking.
Common causes
Worn or bent friction hinges
Friction hinges do a lot of work and are exposed to the weather. Over time they can corrode, loosen or bend, especially if a window has caught the wind while open. The sash then drops or twists, so it catches on the frame and the locking points miss the keeps. A worn hinge is a stock part and is usually replaced on the same visit.
A handle that spins or will not turn
If the handle turns freely without moving anything, the spindle or the gearbox has usually failed. If it will not turn at all, the gearbox may have jammed. Do not force it, as that can break the gearbox and leave the window stuck open or shut.
Keeps out of line
If the window closes but the handle is stiff to lock, the keeps on the frame may need adjusting so they meet the locking points cleanly.
Snapped or loose stays and restrictors
Stays and restrictors that limit how far a window opens can break, especially on upstairs windows. They are worth replacing promptly, particularly in children's rooms.
Swollen or sticking timber windows
Wooden windows can swell in damp weather and stick in the frame. Easing them, and sorting the paint and seals, is a carpentry job rather than a reason to replace them.
What you can check yourself
- Look at the gap around the closed sash. It should be roughly even.
- Open the window and check the hinge screws are tight and the hinge arms are straight.
- Clear any dirt or debris from the hinge tracks and the frame.
- Lightly lubricate the moving parts, following the manufacturer's guidance.
Avoid bending hinges back by hand or taking the gearbox apart. It is easy to make things worse.
Is it the window or the glass?
Sometimes people notice a window problem at the same time as misting between the panes. Those are separate faults. A misted unit can be replaced in the existing frame without touching the hardware. Our guide on why double glazing mists between the panes explains more.
Repair or replace?
If the frame is sound, it is almost always worth repairing. Hinges, handles, gearboxes and keeps are replaceable parts. A whole new window only makes sense when the frame itself has warped, cracked or rotted, or if you want to change the style.
Do not leave a window that will not lock
An insecure window is an easy way in, and many insurers expect windows to be locked when the house is empty. If a ground floor window will not lock, get it looked at sooner rather than later.
Need a window looking at?
Steve replaces friction hinges, handles, gearboxes and stays, and realigns windows that will not close, across Kington, Hereford and north Herefordshire. Timber and sash windows are covered as well as UPVC.
See window repairs and replacement, misted and broken double glazing and lock repairs, or call 07948 117374.