Most uPVC casement windows lock with an espagnolette: turning the handle drives a metal strip hidden in the edge of the sash, which pushes shootbolts or mushroom cams into keeps on the frame. A window that will not lock usually has a broken handle, a worn or snapped espagnolette, keeps that have moved, or a sash that has dropped on its hinges. We find which it is, replace the faulty part and set the window so it locks without force.
How does a uPVC window lock work?
Unlike a door, a typical uPVC window has no key barrel doing the work. The locking happens along the opening edge of the sash:
- HandleOften a locking handle with its own small key. It has a spindle that passes into the gearbox.
- Espagnolette or gearboxThe strip in the sash edge that converts the handle’s turn into a sliding movement. On older windows it may be a single-point “cockspur” instead.
- Shootbolts or camsPins or mushroom heads that slide along with the strip, sometimes extending into the top and bottom of the frame.
- KeepsSmall plates or blocks screwed to the frame that the cams engage with and pull the sash tight against its seals.
Tilt-and-turn windows use a more complex gear with a mis-operation device, and repairs to those are covered separately on our tilt and turn window repair page.
What is causing my window not to lock?
| What you notice | Most likely cause |
|---|---|
| Handle turns freely but nothing happens | Broken handle spindle or a snapped espagnolette |
| Handle will not turn far enough to lock | Cams are hitting the keeps – the sash has dropped or the keeps have moved |
| Handle jams half-way | Worn or seized gearbox, or debris in the mechanism |
| Window locks but rattles or lets in a draught | Keeps worn or set too loose, or seals flattened |
| Window stuck shut, handle will not move | Failed gearbox or a sheared espagnolette |
The single most useful test: open the window and turn the handle through its full range. If it moves smoothly when the window is open but jams when it is closed, the mechanism is probably fine and the sash is out of line with the frame. That is often a hinge problem – see uPVC window hinge repair.
When is it just the handle?
Sometimes the lock gear is perfectly sound and only the handle has failed – a cracked casting, a spindle that has sheared, or a lost key for a locking handle. In that case a new handle with the right spindle length and fixing centres solves it. Our window handle replacement page covers that in detail. We always check the espagnolette before assuming it is the handle, because a new handle on a broken gearbox will not help.
Do not force a handle that has stopped turning. On windows above ground floor, a sash that suddenly releases can swing out, and forcing the handle can shear the gearbox and leave the window stuck open or shut. Please do not lean out of upstairs windows to work on locks or hinges.
How we repair uPVC window locks
- Find out the symptoms. On the phone we ask how many windows are affected, whether the handle turns, and whether the window is stuck open or shut. Photos of the handle and the sash edge help us identify the hardware.
- Test open and closed. At the visit we separate a lock fault from a sash alignment fault.
- Identify the gear. We measure the backset, the length of the strip, and the position of the cams so a replacement matches. Some older systems are no longer made, so we find a compatible alternative.
- Replace or adjust. We replace the espagnolette, handle or keeps as needed, and adjust the sash if it has dropped.
- Test every position. We lock, unlock and open the window several times and check the sash pulls tight against its seals.
Common parts can often be fitted at the first visit if we carry them; less common ones are ordered and fitted on a return visit.
Window security, child safety and escape
A window lock does three jobs: keeping intruders out, keeping the weather out, and letting you open the window easily when you need to. Some practical points:
- Ground-floor and easily reached windows benefit most from locking handles and multiple locking points.
- In children’s rooms and on upstairs windows, window restrictors can limit how far the window opens. They should be releasable by an adult on windows that are used as a means of escape.
- Keep keys for locking handles somewhere close by but out of reach of children, so the window can be opened quickly in an emergency.
- A light oil or silicone spray on the cams and keeps once or twice a year, as the hardware maker recommends, keeps everything moving freely.
Window locks in Liverpool homes
Window locks are a routine part of the main repair service we offer. Much of the uPVC across Liverpool was fitted between the 1980s and the 2000s, and window hardware from that period is now wearing out in large numbers. We see it in the inter-war semis of Allerton and Childwall, and in post-war housing in areas like Speke, where whole houses of windows were fitted at once and the gear is the same age. In exposed spots near the coast, a lock that no longer pulls the sash tight soon shows up as a draught or a wet sill after wind-driven rain.
What affects the cost of a window lock repair?
The make and type of mechanism, whether a compatible part is still available, the number of windows, whether the sash needs realigning as well, and access to upstairs windows. A handle swap is simpler than replacing a full espagnolette. We quote after seeing the windows, and our double glazing problems guide explains how lock, hinge and seal faults often go together.
If the windows are still covered by an installer’s guarantee, check that paperwork before booking a repair with anyone else.
Window will not lock?
Call 07777 659786 or send the form with a short description – and a photo of the handle and the edge of the sash if you can. We will call back and arrange a visit as part of our uPVC window repairs in Liverpool and Merseyside.
Frequently asked questions
Why does my uPVC window handle turn but not lock?
If the handle turns freely without moving the locking cams, the spindle may have sheared or the espagnolette inside the sash may have snapped. If the handle moves but stops before the locked position, the cams are probably hitting the keeps because the sash has dropped or the keeps have moved. The fix is different for each.
Can you repair a uPVC window that is stuck shut?
Usually, yes. A window stuck shut normally has a failed gearbox or a broken espagnolette holding the cams in the locked position. We release the mechanism carefully without damaging the frame, replace the faulty part and test the window. Please avoid forcing the handle, as that can make it harder to open.
Can you get parts for old uPVC windows?
Many older locking systems are still available, and where the original is not, there is often a compatible replacement with the same backset and cam positions. We measure the existing gear and match it. Occasionally a small adaptation to the keeps is needed so a modern part works with an older frame.
Is it the handle or the lock that is broken?
Take the handle off, if it is easy to do so, and turn the spindle hole in the sash with a suitable tool. If the cams move, the gear is working and the handle is at fault. If not, the espagnolette or gearbox has failed. We always check this before ordering parts.
Should every window in the house have locking handles?
Locking handles are most useful on ground-floor and easily reached windows. On windows used as a means of escape, make sure the key is kept nearby so the window can be opened quickly. Restrictors are another option for upstairs rooms, as long as an adult can release them in an emergency.