Patio & French door locks
Patio or French door won't lock? Usually it's dropped, not broken.
Wolverhampton, Stafford and Cannock. Honest diagnosis: rollers, alignment, mechanism or cylinder.
A sliding patio door that will not lock has usually sunk on its worn rollers so the hooks miss their keeps, and French doors that will not lock are usually out of alignment or missing their slave-leaf shoot bolts. In both cases the lock itself is fine, the fix is an adjustment from £90, and the "new mechanism" or "new doors" quote you got over the phone was for a fault you do not have. Run the three checks below (the lift test alone settles most sliding-door calls) and you will know which fault yours is before you ring anyone. If you still need me, the all-in price is agreed on the phone before I leave the van.
- No Call-Out Fee
- No VAT Added
- Standard DBS Checked
- £1M Insured
- 12 months Guarantee
Patio door won't lock? Three checks before you call anyone
Patio and French doors are where phone misdiagnosis costs people the most, because the two most common faults (worn rollers on a slider, alignment on French doors) are both invisible to anyone quoting from a price list. These three checks take two minutes and usually name the fault for free.
-
The lift test: raise the sliding panel gently as you lock it
Grip the handle, lift the sliding panel upwards a few millimetres, and try the lock while you are taking its weight. If it locks while lifted, you have just diagnosed the fault: the roller cartridges under the panel have worn, the door has sunk, and the hooks are missing their keeps. Nothing about the lock is broken. That is a roller adjustment or replacement plus a keep re-alignment, not a new mechanism, whatever anyone quotes you over the phone.
-
Feel the slide: one finger, or a shoulder?
A healthy sliding patio door moves with a finger or two. If yours won't slide without a shoulder behind it, or has been getting heavier for months and now grinds along the bottom track, the rollers are worn or seized and the panel is dragging instead of rolling. Before anything else, vacuum the bottom track and wipe it clean, because grit alone can do this and costs nothing to fix. If it is still heavy on a clean track, it is the rollers, and the heaviness and the "won't lock" are the same fault.
-
French doors: try locking with the door standing open
Swing the master leaf (the one with the handle) open, lift the handle and turn the key in mid-air. If everything throws smoothly with the door open but refuses with it closed, the mechanism is fine and the problem is alignment: the doors have dropped on their hinges, or the slave leaf's shoot bolts are not seated so there is nothing solid to lock against. If the handle will not lift even with the door open, the gearbox itself has failed. Thirty seconds, and it tells me exactly what to bring.
Rollers, alignment, mechanism or cylinder: which is it?
Match your symptom to one of the four branches below. The first two are adjustment jobs with no new parts, and they cover the majority of patio door lock repair calls I take. Only the last two involve replacing anything.
-
If the sliding door locks while you lift it, or has become heavy to slide...
Worn or collapsed roller cartridges. The panel runs on small wheeled cartridges underneath, and when the bearings wear or the nylon wheels split, the panel drops onto the track: heavy to slide, and the hook bolts miss their keeps. The fix is adjusting the rollers back up via the screws in the door edge, or replacing the cartridges where they are past saving, then re-aligning the keeps. From £90 for the visit, replacement rollers priced on the day by pattern. Not a new lock, and definitely not the new doors a window company will quote.
-
If your French doors lock fine standing open but not closed...
Alignment, not a broken lock. Either the leaves have dropped on their hinges over time, or the slave leaf is loose because its shoot bolts at the top and bottom are not fully seated, so the master leaf has nothing firm to lock against. Hinge adjustment and shoot-bolt seating is a doorstep job from £90, usually no parts at all. This is the single most misdiagnosed French door fault: it feels like a lock failure, so people get quoted for a mechanism they do not need.
-
If the handle or mechanism is dead no matter what: door open, door closed, lifted or not...
The mechanism has genuinely failed. On a slider that is the hook-bolt lock or its gearbox; on French doors it is the multi-point gearbox in the master leaf, the same mechanism family as any uPVC front door. Like-for-like replacement is from £145. The one habit that kills these early is forcing a misaligned door for months: the gearbox carries the strain the rollers or hinges should have been taking. The mechanism-level detail lives on my door won't lock guide.
-
If the key will not turn, or you have lost the patio door key...
The cylinder. On modern sliders and virtually all French doors that is a standard euro cylinder, changed from £90 with new keys cut on the spot, and worth upgrading to anti-snap on French doors (the cylinder is their weak point: see the anti-snap guide). Some 1980s and 1990s aluminium sliders carry proprietary cylinders instead: send me a photo of the lock face on WhatsApp and I will source the right pattern before I set off. Sizing matters on thicker doors too: the euro cylinder size guide shows how to measure.
What window companies will not tell you
Replacement rollers exist for almost every sliding patio door ever fitted in this country, including the 1980s and 1990s aluminium ones. "Parts are no longer available" usually means "we would rather quote you for new doors". A roller and keep visit is from £90; replacement doors start around two thousand pounds. When the door slides with one finger and locks first time afterwards, you will know which one you needed.
Sliding patio doors vs French doors: what fails on each
People say "patio doors" for both, but they are different machines and they fail differently. Knowing which you have tells you most of the diagnosis before you touch anything.
Sliding
One panel rolls past another on a bottom track
Lives or dies by its roller cartridges. When they wear, the panel drops, the slide goes heavy, and the hook bolts miss their keeps. Fix: roller adjustment or replacement plus keep re-alignment. Security watch-point on older doors: the lifting attack, countered with anti-lift blocks in the top track.
French
Two hinged leaves meeting in the middle
The master leaf locks against the slave leaf, so the slave's top and bottom shoot bolts must be seated first. Most faults are hinge alignment or unseated shoot bolts, not the lock. Security watch-point: the euro cylinder, which wants to be anti-snap because it sits on the most secluded door of the house.
What they share: both are usually the most private door on the property, tucked round the back where a burglar gets time and cover. That is why insurers commonly want key-operated locks on patio and French doors listed as final exits, and why I would rather upgrade a cylinder and fit anti-lift blocks than sell you anything bigger. The wider picture on which lock suits which door is on my types of door locks guide.
Patio door won't lock in hot weather
Frames and panels expand in the heat, tolerances tighten, and a patio door that was already marginal (a slightly dropped slider, slightly tired hinges on French doors) stops locking on hot afternoons and behaves again in the evening. Everest's own advice for their patio doors says the same: heat expansion can stop the lock engaging, and the door returns to normal as it cools. If your door only misbehaves on warm days, the fault is clearance, not the lock. A roller or hinge and keep adjustment gives the door its summer margin back, from £90, and nobody should be quoting you a mechanism for it. Dark composite front doors show this seasonal pattern even more strongly, which I cover in full on the composite door locks guide.
Recent patio and French door call-outs
Three recent calls across Wolverhampton, Stafford and Cannock: one set of collapsed rollers on a 1990s slider, one French-door alignment that was never a lock fault, one genuine out-of-hours mechanism failure. Real-pattern situations, real prices on the receipt, next to what the customer had been quoted elsewhere. Customer details lightly anonymised at their request.
-
Tuesday 7 July 2026 at 2.20pm · Wolverhampton
Mr Ken B., WV11, Wolverhampton
Aluminium sliding patio door, fitted sometime in the 1990s, needed two hands and a run-up to slide and had not locked properly for months. A window firm had quoted for replacement doors and told him parts "weren't available any more".
Quoted elsewhere £1,850Paid to me £130Both roller cartridges had collapsed: bearings rusted solid, one nylon wheel split in half. Universal tandem rollers matched to the pattern, panel jacked back up to height, keeps re-aligned, track cleaned. The door now slides with one finger and locks first time. Parts for old sliders are almost always still available: "not available" usually means "we would rather sell you doors".
-
Saturday 11 July 2026 at 9.40am · Stafford
Mrs Eleanor W., Stafford
uPVC French doors onto the garden would not lock after the decorators had been in. Handle lifted halfway then stopped dead. She had been quoted for a new locking mechanism over the phone by a national number.
Quoted elsewhere £280Paid to me £90The decorators had opened the slave leaf and nobody had re-seated its shoot bolts, so the master had nothing to lock against, and the constant trying had pulled the top hinge out of line. Seated the bolts, quarter-turned the hinges back into alignment, showed her how the slave leaf secures so it never catches her out again. No parts. The mechanism was never broken.
-
Wednesday 15 July 2026 at 9.05pm · Cannock
The Nowak family, WS12, Cannock
Sliding patio door hook lock failed in the unlocked position at 9pm: the door would shut but nothing would throw, and they could not secure the back of the house for the night. Out-of-hours call with young kids in the house.
Quoted elsewhere £450 OOHPaid to me £230The hook lock's gearbox had stripped, a genuine failure after years of the door being slammed against a slightly dropped keep. Secured the door that night with a like-for-like mechanism off the van, out-of-hours rate, about 45 minutes. Set the rollers and keeps at the same time so the new mechanism is not fighting the drag that wore out the old one.
The mechanics above are documented by the door trade itself: Everest's patio door advice notes the sliding door "will need to slide freely into place to be able to lock correctly" and that heat expansion can stop a patio door locking until it cools, while Aspire Doors' French door guide puts most French door faults down to "misalignment of the doors which happens over time". The multi-point mechanics behind the master leaf are the same ones the Master Locksmiths Association describes for uPVC doors generally. My from-prices for the work above start at £90 for a roller, hinge or keep adjustment visit and £145 for a like-for-like mechanism.
What customers say about door and lock call-outs
Verified Google reviews from real customers across Wolverhampton, Stafford, Cannock and the surrounding villages.
I locked myself out my house and phoned Sean at 1.32am. He arrived at my house in Bilston 35 minutes later. He lives 30 minutes away. He was very professional and tidy. I would recommend him to anyone. Within 1 hr and 15 minutes of calling him he had come out, sorted my lock and on his way home. You can call him anytime and he will get to you asap. Worthy of the 5 star rating
Thankyou for your review Shell. Real pleasure to assist you both with your emergency call-out. Sean - Lockerfella Locksmiths 24/7
I contacted Sean in a panic after our back door wouldn’t lock at 21:15 on a Sunday night. Sean came back with a price almost immediately and offered to come and look at it straightaway. At my request, I asked him to come Monday morning and he sent me an ETA and turned up bang on time. Sean quickly diagnosed the problem, he had to go off to get a a part and when he was on his way back to me, he even shared his location via WhatsApp so I knew when he would be back. Part fitted, worksite cleaned up and he was on his way. Reasonably priced, fantastic communication from start to finish and a great bloke to speak too as well. Thanks Sean, you’re an absolute star!
Absolute pleasure meeting you and your wife today in Codsall / Wolverhampton. I'm really pleased I was able to repair your faulty upvc door mechanism. Thankyou for the glowing review....it's really appreciated. Sean - Lockerfella Locksmiths 24/7
Phoned this lovely man this morning before 8am , it's now 11.28 am and my lock is fixed , thank you Sean , as I live alone i was feeling vulnerable, thank you so much , fir your prompt response
Thankyou so much for your review Maureen. Real pleasure assisting you today in Walsall to replace your Euro Cylinder and Door handles. Sean ☺️
Used Sean to replace patio door lock in Rugeley. Great communications, fast & friendly service. Reasonable price agreed before arrival. Would highly recommend.
Thankyou for the review guys! Pleasure helping you today with the new barel and keys. Sean - Lockerfella Locksmiths 24/7.
We needed a lock change in Wolverhampton urgently and Sean was great ! Friendly and did a professional job would highly recommend!
Thankyou so much for the review guys! Sean - Lockerfella Locksmiths.
I had a great experience with Lockerfella Locksmith, especially with Mr Sean. He was professional, patient, respectful, and took the time to make sure everything was done properly. My door lock turned out to be much more difficult than expected, but Sean stayed calm and worked hard until the job was completed perfectly. I really appreciated his honesty, kindness, and excellent workmanship. I highly recommend Sean and Lockerfella Locksmith to anyone looking for a reliable locksmith. Thank you again, Sean, and I wish you continued success in your business!
It was an absolute pleasure helping you today Saeideh in Wolverhampton. Thankyou so much for the kind words. Sean - Lockerfella Locksmiths 24/7.
Sean came out to Atherstone, Warks. (CV9) today and mended our jammed shut 1980's UPVC front door. One of the bolts had failed so wouldn't release, and being an old mechanism a replacement turned out to be unavailable. Fortunately thanks to his knowledge and experience Sean was able to provide us with a secure, permanent fix and save us the potential expense of replacing the door. We 100% recommend him and will definitely use him again if any other lock problems crop up.
Thankyou for the fantastic review Isobel. It was my pleasure assisting you today. If you ever need any help in the future I will be here to help. Sean - Lockerfella Locksmiths 24/7.
Absolutely brilliant guy! Sean was in in seconds after I stupidly locked myself out. He kept me updated with what he was doing and was very professional and friendly too! Most importantly he didn't charge the earth, was extremely honest and no upfront or hidden fees. He's great for anyone local to Sutton Coldfield and surrounding areas
Thankyou for your review Richard. Very much appreciated. And an absolute pleasure meeting you and assisting you tonight. Sean - Lockerfella Locksmiths
Prices
What does patio door lock repair and replacement cost?
The figures below are the floor prices for the patio and French door lock jobs I am called to most. They include attendance, diagnosis and labour, with no separate call-out fee. A full patio door lock replacement uses the same cylinder and mechanism parts as any uPVC door, so the prices match; replacement roller cartridges are priced on the day because sliders take different patterns. I quote the all-in figure on the phone before I leave the van. The full price list with covers and affects sits on the dedicated pricing page.
- Roller, hinge or keep adjustment (dropped slider or French door alignment) from £90
- Euro cylinder change (patio door lock barrel, lost keys, standard cylinder included) from £90
- Hook-lock or multi-point mechanism replacement (like-for-like) from £145
- Out-of-hours emergency (6pm to 8am, weekends, bank holidays) from £170
No VAT added on top. No call-out fee on any of these. Replacement rollers and anti-lift blocks are itemised on the day so you can see exactly what each part cost. See the full price list and what each one covers →
About the locksmith
The locksmith answering your call
I'm Sean Hamilton. I run Lockerfella as a one-man-band. If you ring me about a patio or French door, the first things I will ask are whether the slider locks when you lift it and whether the French doors lock standing open, because those two questions separate a £90 adjustment from a genuine mechanism job. I quote the all-in price on the phone before I leave the van. No call-out fee. No new doors for a door that needed two rollers.
- 30+ years fascinated by locks. I've been picking, stripping and studying locks for the love of it for over 30 years. Lockerfella is what happens when a lifelong interest in how locks work becomes the day job.
- Trained and certified. Certificate of Locksmith Skills from A'Jam Locksmiths covering cylinder, mortice, padlock, wafer and euro lock picking, plus re-keying and mortice bypassing.
- Standard DBS checked, £1M insured, 12 months workmanship guarantee. Redacted DBS and insurance certificates are published on the About page, with originals available to view in person before work starts.
- One man, one van, one phone number. The phone rings on me directly. No call centre. No third-party fitter. If I quote you a price, that's the price you pay.
Common questions about patio and French door locks
Straight answers on sliding doors that will not lock or slide, French doors that will not close, lost patio door keys, hot weather, security, and what each repair actually costs.
Why won't my patio door lock?
On a sliding patio door, the honest answer is that the door has usually dropped, not broken. The panel runs on small roller cartridges underneath, and when the bearings wear or the nylon wheels split, the whole panel sinks a few millimetres, so the hook bolts no longer line up with their keeps in the frame. The quick test: lift the sliding panel gently by the handle as you try to lock it. If it locks while you are taking its weight, the rollers are the fault, and the fix is a roller adjustment or replacement plus re-aligning the keeps, not a new lock. If lifting changes nothing and the mechanism feels dead, the hook lock or gearbox itself has failed, and if the key will not turn it is the cylinder. Tell me which of those you have on the phone and I will bring the right parts.
Why has my patio door become heavy to slide?
Worn rollers, almost every time. A sliding patio door should move with one or two fingers. When it starts needing a shoulder, the roller cartridges under the panel have worn or seized, the panel has dropped onto the track, and you are dragging the door's full weight along the aluminium instead of rolling it. Grit in the bottom track makes it worse, so it is always worth vacuuming the track and wiping it clean first, which is free and occasionally solves it. But a door that has been getting steadily heavier for months needs the rollers adjusted or replaced. Left alone it does not just stay annoying: the dropped panel stops the hooks meeting their keeps, and that is the point people ring me saying the door "won't lock".
How much does patio door lock replacement cost?
It depends which part has actually failed, because a patio door lock is several parts. A euro cylinder change (where the key goes in) is from £90 including a standard cylinder. A failed hook-lock mechanism or gearbox is from £145. A roller adjustment and keep re-alignment visit, which is what a big share of "broken lock" calls actually need, is from £90, and replacement roller cartridges are priced on the day depending on the pattern your door takes. Out-of-hours attendance (6pm to 8am, weekends, bank holidays) is from £170. No call-out fee, no VAT on top, and I quote the all-in figure on the phone before I leave the van.
Why won't my French door lock?
Run the open-door test first: swing the master door (the one with the handle) open, lift the handle and turn the key with the door standing open. If the mechanism throws smoothly in mid-air but will not lock with the door closed, nothing is broken: it is alignment. Either the doors have dropped on their hinges, or the slave leaf (the one without the handle) is not properly secured, because its shoot bolts at the top and bottom are not fully seated, so the master has nothing solid to lock against. Both are adjustment fixes from £90. If the handle will not lift even with the door open, the multi-point gearbox in the master leaf has failed, which is the same mechanism family as any uPVC door and is replaced from £145.
I've lost the key to my patio door. Can you sort it?
Yes. On most modern sliding patio doors and virtually all French doors the lock is a standard euro cylinder, so a lost key is a cylinder change from £90 with new keys handed to you on the spot, and the mechanism itself is untouched. Some older aluminium sliders (roughly 1980s and 1990s) carry proprietary cylinders instead, and those I source by pattern: I will ask you for a photo of the lock face on WhatsApp before I come out so I arrive with the right part rather than a guess. Either way the door does not need drilling in most cases, and it absolutely does not need replacing, whatever a window company quotes you.
Are sliding patio doors easy to break into?
Old ones can be, and it is worth being honest about why: early sliding doors could be lifted off their track from outside, because the panel sits on rollers and the original designs left enough clearance to lift the door clear of its keeps. Modern sliders close that off with anti-lift blocks in the top track and multi-hook locks that clamp the panel to the frame. If yours is an older door, the upgrades that matter are anti-lift blocks, a decent cylinder, and making sure the hooks actually engage (a dropped door that "sort of locks" is a door that is not really locked). French doors are a different picture: their weak points are the cylinder, which wants to be anti-snap (see my anti-snap locks guide), and slave-leaf shoot bolts that people forget to seat. I fit and upgrade all of it, and your home insurer will usually want to see a key-operated lock on any patio or French door listed as a final exit.
Why won't my patio door lock in hot weather?
Same physics as any door in the sun: the frames and panel expand in the heat, tolerances tighten, and a sliding door that was already marginal (slightly dropped, slightly misaligned) stops locking on hot afternoons. Everest's own advice for their patio doors is that heat expansion can stop the lock engaging and the door returns to normal as it cools. If your door only misbehaves on hot days, do not let anyone sell you a new mechanism for it: the lasting fix is a roller and keep adjustment so the door carries enough clearance for summer. Dark composite front doors suffer the same seasonal pattern even more strongly, which I cover on my composite door locks guide.
Ready when you are
Patio door still fighting you? Tell me the symptoms.
Tell me whether it is a slider or French doors, whether it locks when you lift it or with the door open, and how it slides. I will tell you on the phone whether it is rollers, alignment, mechanism or cylinder, and the all-in price. No call-out fee. No deposit. No surprises.
Page last reviewed: . Reviewed by Sean Hamilton, the locksmith behind Lockerfella, under our editorial standards.