Handle spinning, jamming halfway or turning without locking anything? We repair and replace the locking mechanism inside your casement window and leave the frame and glass exactly where they are.
A window lock mechanism repair means taking out the failed locking gear inside the opening sash of a uPVC casement window and fitting a correctly matched replacement. The mechanism is the metal strip set into the edge of the sash, driven by the handle, and the cams or bolts along it are what actually hold the window shut. Once the gearbox wears or a cam shears, the handle can spin freely, stick part way round or turn fully without securing anything. Where the sash and frame are still sound, the mechanism can normally be replaced on its own and the rest of the window stays as it is.
From £175
From £175
From £175
From £175
From £175
From £175
No Hidden Charges
Work Guaranteed
Pay on Completion
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Please note: We do not repair or replace window locks in timber windows and doors, Single glazing, Secondary glazing, Velux windows.
Send us photos or a short video of the window and its handle by WhatsApp. We will work out which locking mechanism it takes and come back with a price.
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Send us photos or a short video of the window and its handle by WhatsApp. We will work out which locking mechanism it takes and come back with a price.
Send a photo or video
Talk to an expert
Send your enquiries
No Hidden Charges
Pay on Completion
Work Guaranteed
Google Reviews
Please note: We do not repair or replace window locks in timber windows and doors, Single glazing, Secondary glazing, Velux windows.
Local experts near you
On all repair work
Years of experience
5-Star rated service
Your window lock does more work than you would think. Every time you turn the handle, a spindle drives a gearbox, and that gearbox pushes cams or bolts along the edge of the sash so they engage with the keeps fitted to the frame.
Wear builds up quietly. Springs tire, gear teeth round off, cams lose their shape and the spindle socket widens. Forcing a stiff handle, slamming the window shut, or years of grit and weather all speed that along.
Once the gear stops travelling its full stroke, the cams no longer seat properly in the keeps. The handle may feel light and vague, stop dead at forty five degrees, or spin all the way round while the sash stays loose.
From there it stops being an annoyance and becomes a security and comfort problem. A sash that is not pulled tight against the seals lets draughts through, rattles in the wind and gives very little resistance to anyone trying the window from outside.
Fitting a mechanism that matches the original backset, gearbox height and cam layout usually brings the window back to a firm, even close without touching the frame or the glass.
Fix more windows on the same visit and the price per window drops.
Sort more than one window on the same visit and the price per window drops. Secure, easy to lock and draught free for less.
20% off when you repair 3 or more windows
A sash that locks tight seals properly and keeps draughts out
Locks that engage firmly every time you turn the handle.
All repairs come with 1 year guarantee including parts
Pay standard price
GET 20% OFF
Discount applies to uPVC casement windows that open outwards on the same property
Send photos or a short video on WhatsApp for a free quote with no obligation.
Prices cover supplying and fitting the replacement locking mechanism, plus resetting the keeps on the frame so the sash closes evenly. Oversized, unusually heavy, externally glazed or awkward to reach windows are quoted individually.
AUTUMN SPECIAL
Save 20% on lock repairs across 3 or more windows
When the handle on a uPVC casement window stops locking, the answer is almost never a whole new window. Window Fixers replaces failed espagnolette and shootbolt locking mechanisms across London, matching the new gear to the backset, gearbox height and cam pattern of the original so the sash closes the way it was designed to. We work on everything from older cockspur handle locks to modern multipoint strips, with clear pricing, a 1-year parts and workmanship guarantee, and no pressure to replace hardware that is still doing its job.
A handle that will not lock rarely means a new window. We fit a new mechanism and leave your existing frame, sash and glass alone.
Every lock mechanism we fit is covered for a full year, parts and workmanship included.
Send a photo of the window and handle for an initial price. Lock mechanisms from £175 per window, no call-out charge and nothing added later.
If we cannot complete the lock repair we agreed, you do not pay for work we have not finished.
We match the replacement to the backset, gearbox height, cam layout and handle centres already fitted to your window.
Espagnolette strips, shootbolts, gearboxes, cockspur locks and restrictors in outward opening uPVC casements, right across London.
We keep window lock repairs simple. Clear answers, a fixed price before anything is booked, and a window that locks properly when we leave.
Free assessment & fixed quote
Email or WhatsApp us a photo or video of the window, ideally the full opener plus a close-up of the handle and the lock strip along the edge of the sash. That tells us the mechanism type, backset and cam layout you need, and we send back a fixed price. No call-out charge.
Fitted and tested, usually same day
Our technician removes the failed mechanism from the edge of the sash and fits the matched replacement. The keeps on the frame are then reset so every cam or bolt engages evenly, and the handle is adjusted to turn cleanly through its full stroke. No mess, and no damage to your frames or glass.
Guaranteed for 12 months
Before we leave we run the handle with you, several times, and check the window locks without lifting, shoving or holding the sash. Compression feels even along the edge and the rattle is gone. Parts and workmanship are guaranteed for a year, and you pay once the job is finished.
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Send a photo or video of the handle and window and we will reply quickly.
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Speak to someone who repairs these locking mechanisms every day.
Send enquiries
Send us the details and we will come back to you with a price.
Every lock mechanism replacement is backed by our 1-year parts and workmanship guarantee, so you know the new gear was fitted correctly and the window was tested before we left.
A failed locking mechanism is a hardware fault, not a reason to buy a window. Where the sash and frame are sound, we swap the mechanism and reset the keeps so the window closes firmly again.
Window Fixers specialises in uPVC casement window lock repairs and mechanism replacement across London. If the handle spins without catching, jams part way round, or the window has to be forced before it will lock, the locking gear inside the sash is usually the culprit. We fit a matched replacement mechanism, reset the keeps on the frame and keep your existing window in place wherever we can. Every lock repair is backed by our 1-year repair guarantee.
Straight answers on failed gearboxes, spinning handles, what a lock replacement costs, how long it takes and our 1-year parts and workmanship guarantee.
The usual signs are a handle that spins with no resistance, sticks part way through its turn, or turns fully while the sash stays loose. You may also find yourself lifting or pushing the window before the handle will go round. Other parts can produce similar symptoms, so the window is worth checking properly before anything is ordered.
It is the long metal strip fitted into the edge of the opening sash on most uPVC casement windows. The handle drives a gearbox in the middle of that strip, which slides cams or rollers along it so they engage with the keeps on the frame.
That normally points to a broken gearbox or a sheared drive inside the mechanism. The handle is still turning the spindle, but nothing is being pushed along the sash, so no cam ever reaches its keep.
Usually not. The locking mechanism is a separate component. Where the sash and frame are still sound, it can be taken out and replaced while the window itself stays exactly where it is.
Yes. The cams are what pull the sash tight against the seals. If they are worn or no longer reaching the keeps, compression drops off and air finds its way through, often with a rattle in the wind.
Only where it is needed. A handle and a mechanism are separate parts and one can fail without the other. If the handle is snapped, loose on the spindle or a poor match for the new gear, we will tell you before the work is booked rather than after.
Stiffness usually comes from a mechanism running dry or starting to bind, or from cams fighting against keeps that have drifted out of line. Forcing a stiff handle is what tends to snap the gearbox, so it is worth looking at early.
If a cam or bolt has jammed in its keep, or the gearbox has failed part way through its travel, the sash can be held closed with no way of releasing it from the handle. This can normally be freed and the mechanism replaced without damaging the frame.
Most first-floor casement lock repairs are carried out from inside the room, depending on the window design and safe access. We check access before confirming the work.
Our lock repair service covers uPVC and aluminium casement windows. Send us a photo if you are not sure which you have and we will tell you either way.
That means the cams are not lining up with the keeps on the frame, and lifting the sash brings them back into line for a moment. The cause may be the mechanism, the keeps, the hinges or a mix of all three, so it needs looking at properly.
Sometimes. Where the mechanism itself is sound and the real problem is alignment, resetting the keeps and squaring up the sash can be enough. Once gear teeth or cams are worn or broken, replacement is the repair that actually lasts.
A shootbolt mechanism drives bolts out of the top and bottom of the sash into keeps in the frame, either instead of or alongside cams along the edge. They are common on taller openers and give a firmer clamp across the full height of the window.
Yes. We can fit restricted opening hardware that limits how far a casement window swings, which many people want on upstairs rooms. Tell us the room and the window and we will confirm what suits it.
Not quite. A snapped handle is its own part and often a quicker job than a mechanism. That said, handles usually snap because something behind them was stiff, so we check the mechanism at the same time.
Yes, both. We work on outward opening uPVC and aluminium casement windows, side-hung and top-hung alike.
Usually. Mechanisms are identified by backset, gearbox height, cam spacing and handle centres rather than by brand name, so an equivalent can normally be sourced even for windows that are decades old.
Most single window lock replacements are a straightforward visit. The actual time depends on the sash size, the mechanism type, access and what condition the keeps are in. We will tell you once we have seen your photos.
Send photographs or a short video on WhatsApp. The most useful shots are the whole window, a close-up of the handle, and the edge of the open sash showing the lock strip and its cams. We will identify the mechanism and come back with a price, or tell you what else we need to see.
Replacing the locking mechanism in a standard uPVC casement window costs from £175 per window. That covers the new mechanism, fitting it, and resetting the keeps on the frame so the sash closes evenly. It applies to both side-hung and top-hung outward opening casements, whether they use an espagnolette strip or a shootbolt.
Window handles are a separate part and start from £108 for the first handle on a visit.
If three or more windows at the same property need work, a 20% multi-window discount applies.
These prices are for standard, safely accessible uPVC casement windows. Very large or unusually heavy openers, externally glazed windows, awkward access, and anything needing specialist equipment or extra work are quoted individually.
Send us a few photos or a short video of the window and handle and we will confirm the right mechanism and give you a clear price before anything is booked.
See how a failed locking mechanism gets put right without the cost of a new window. Each job below shows the customer’s own photos, the repair carried out and the final price paid.
Side hung uPVC casement window lock mechanism replaced. Total cost £175 all in
Top hung uPVC casement window lock mechanism replaced. Total cost £175 all in
Top hung uPVC casement espagnolette lock replaced. Total cost £175 all in
Side hung uPVC casement shootbolt lock replaced. Total cost £175 all in
Side hung aluminium casement window lock mechanism replaced. Total cost £175 all in
Side hung uPVC casement window handle and lock replaced. Total cost £175 all in
Window Fixers repairs and replaces uPVC casement window locking mechanisms throughout London, in houses, flats, rented homes and commercial premises. Send us a photo or short video of the window and handle and we can usually name the fault and give you an initial price before anything is booked.
Based in London and providing mobile window repair services across Greater London, including..
Barnet, Enfield, Haringey, Camden, Islington, Hackney, Waltham Forest, Newham, Redbridge, Barking & Dagenham, Havering, Greenwich, Lewisham, Southwark, Lambeth, Wandsworth, Merton, Croydon, Bromley, Sutton, Kingston upon Thames, Richmond upon Thames, Hounslow, Ealing, Hillingdon, Brent, Harrow, Hammersmith & Fulham, Kensington & Chelsea and Westminster.
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