Patio & French Door Locks
Patio sliders and French doors are a popular feature in Wandsworth homes — from garden-facing flats along Garratt Lane to Victorian conversions in Earlsfield with original rear extensions — but their locking systems are quite different from a standard front door and need specialist attention when they go wrong. Whether a multipoint lock has seized mid-winter, a French door mortise lock is no longer engaging properly, or a uPVC patio slider has dropped on its track and left the hook bolts unable to reach their keeps, the fault usually lies in a component that a general handyman will not carry or know how to source.
Open 24 hours, 7 days a week · Fully insured
Earlsfield Locksmith is a 24/7 mobile locksmith service covering the whole of Wandsworth. Our trained and insured technicians carry a range of multipoint lock gearboxes, euro cylinders, espagnolette rods, and French door lever lock hardware in the van, so most repairs and replacements are completed in a single visit. We come to you — there is no shop to drop keys at, and no waiting in a queue. If your patio or French door has stopped securing the way it should, call 020 3757 5840 and we will send someone straight away.
What we do
Available 24/7
Day, night, weekends and bank holidays — a real local locksmith answers and sends a fully-stocked van.
We come straight away
Based in Wandsworth, we send a locksmith straight away — we're usually with you in about 30 minutes.
Fully insured
Vetted locksmiths, a clear price on the phone, and no surprise add-ons when we arrive.
Damage-free entry
We pick and bypass locks the right way, so most lockouts are solved without drilling anything.
How Patio and French Door Locks Actually Work — and Why They Fail
A uPVC patio slider uses a multipoint locking system driven by a central gearbox. When you lift the handle and turn the key, a series of hook bolts, mushroom-headed bolts, and rollers shoot out along the door slab and engage with keeps set into the door frame. Over time — especially in a property that settles, or where the frame has been exposed to heavy rain and sun — the door drops fractionally on its rollers. That tiny drop is enough to misalign the hooks with their keeps, putting enormous strain on the gearbox mechanism every time someone forces the handle upward to get the door to lock. Eventually the gearbox snaps internally and the door either will not lock at all or locks on only one bolt.
French doors present a slightly different picture. Many Wandsworth properties have double uPVC French doors fitted with an espagnolette — a slim rod and gearbox system that runs the full height of the active leaf and shoots bolts into the head and threshold. Others, particularly older timber French doors on Victorian terraces near Summerstown or Colliers Wood borders, use a traditional French door mortise lock set fitted into the edge of the door, often paired with surface-mounted cremone bolts or flush bolts on the passive leaf. A french door mortise lock can wear, corrode, or simply reach the end of its design life, and when the case cracks internally the door will not deadlock. Neither French doors nor patio sliders give much visual warning before they fail — which is exactly why residents contact us both for planned upgrades and for genuine emergencies.
Repairing vs Replacing: What Our Technicians Assess on Arrival
When a technician arrives at your Wandsworth address — usually within about 30 minutes of your call — the first task is a systematic diagnosis before any parts are touched. For a patio slider this means checking the roller height, testing each locking point in turn, inspecting the gearbox cam for damage, and looking at the condition of the euro cylinder. Many apparent gearbox failures are actually a dropped door that just needs roller adjustment; in those cases the fix is quick and no new parts are needed. Where the gearbox itself has failed, we match the replacement by measuring the case dimensions, PZ (centre-to-keyhole) distance, and backset, then fit a compatible unit from stock. Because uPVC door systems are made by dozens of manufacturers, having the right measuring knowledge matters far more than simply swapping like-for-like by eye.
For French doors the assessment covers the mortise lock or espagnolette gearbox, the condition of the keeps, the passive leaf's flush bolt alignment, and — critically — the euro cylinder. Cylinders on French doors are exposed at handle height on external faces and are a known snapping target. If the existing cylinder protrudes more than a few millimetres beyond the handle rose, we will recommend an anti-snap, anti-pick euro cylinder as part of any door lock replacement London job. We confirm the exact, up-front price on the phone before any work begins — the final quote depends on the specific lock or gearbox required, the time of day (evenings, weekends, and bank holidays affect call-out charges), and travel distance — so there are no surprises when we arrive. Call 020 3757 5840 to get your quote before we set off.
French Door Lever Locks, Mortise Sets, and Handle Configurations
One of the most common questions we receive is about how to lock French doors with lever handles when the existing mechanism has become stiff or refuses to engage the deadlocking position. On most uPVC and modern timber French doors the answer lies in the gearbox behind the backplate rather than the handle itself — the handle is simply the actuator, and replacing it alone rarely solves a locking fault. Where a french door knob lock or lever handle has been fitted to an older door originally designed for a different backset, we can assess whether an adaptor plate is viable or whether the door edge needs to be mortised to a new depth to accept a correct-sized french door mortise lock set.
For timber French doors — still common in older Earlsfield terraces and Wandsworth Common-side Victorian semis — a 5 lever rebated mortice lock for french doors is often the most appropriate solution. The rebated version accounts for the small step (the rebate) where the two door leaves overlap, so the lock case and faceplate sit flush and the bolt throws correctly into the striking plate on the passive leaf. These locks are available in BS 3621-compliant versions, which many home insurance policies require on external doors. Fitting one correctly requires accurate marking out of the mortice pocket, correct chisel work on the rebate, and precise keep alignment — work that our experienced technicians carry out as a routine part of upvc door lock repair London callouts, taking care to avoid unnecessary damage to the door or frame throughout.
When You Need an Emergency Locksmith London for Patio and French Door Lockouts
A failed patio or French door lock is not just inconvenient — in many Wandsworth homes, particularly garden flats or ground-floor conversions, the rear door is the only practical exit to the garden, and in some layouts it is the primary means of escape in an emergency. If you are locked out London-side of your patio slider with no other way back into the property, or if the door has locked itself in the closed position and will not release from inside, the situation calls for a 24 hour locksmith London response rather than a wait-until-morning approach. Our team is available every hour of every day, including bank holidays, and we operate across the SW postcodes that cover Wandsworth, Earlsfield, Tooting, Southfields, and surrounding areas.
When a technician reaches you, entry is always approached in the least destructive way possible. For uPVC patio and French doors that means trying the cylinder and testing the gearbox engagement before any other method is considered — damage-free resolution is the aim on every job. If the cylinder itself must be removed and replaced, that is handled cleanly and the new cylinder is supplied and fitted as part of the same visit. Once inside, we do not simply leave: we diagnose why the lock failed, advise on whether the gearbox needs replacement, and carry out any door lock replacement London work there and then if the right parts are on the van. We work in the same professional way whether the callout is a planned upgrade on a Monday morning or an emergency locksmith London response at 2am on a Sunday — the standard does not change.
Frequently asked questions
My uPVC patio door handle lifts but the door will not lock — what has gone wrong?
In most cases the gearbox inside the door has failed. The gearbox is the central mechanism that translates your handle movement into bolt engagement along the edge of the door. When the internal cam or carrier strip breaks, the hooks and rollers simply stop moving even though the handle still lifts freely. A secondary cause is a dropped door — if the rollers at the bottom have compressed or adjusted downward over time, the hook bolts no longer align with their keeps in the frame, which puts so much stress on the gearbox that it eventually fails. A trained technician can distinguish between the two causes quickly and advise whether roller adjustment alone is enough or whether a gearbox replacement is needed.
Can you replace a French door mortise lock without damaging the door?
Yes, in the great majority of cases. Replacing a mortise lock for French doors is a straightforward process for an experienced locksmith: the old case is removed, the mortice pocket is checked for size compatibility, and the new lock is fitted. If the replacement case has slightly different dimensions we may need to pare the pocket very slightly, but this is controlled work done with hand tools and leaves the door fully intact. Where a 5 lever rebated mortice lock for French doors is being fitted for the first time on a door that previously had only surface bolts, a little more work is involved — but we still aim for a clean, damage-free result and confirm exactly what is involved before starting.
How much does it cost to repair a patio door lock in Wandsworth?
There is no single fixed price because the final quote depends on several factors: which gearbox or lock component is needed and whether it is in stock on the van, the time of day (a callout on a weekday afternoon and one at midnight on a bank holiday will differ), travel distance within Wandsworth, and whether the euro cylinder also needs replacing. What we always do is confirm the exact price clearly over the phone before anyone sets off, so you know the full cost before agreeing to the visit. There are no hidden additions once work begins.
My French doors have lever handles — how do I know if they are actually deadlocking?
This is a very common concern. On most uPVC French doors with lever handles, lifting the handle compresses the multipoint bolts and turning the key brings the door into the deadlocked position — meaning the bolts cannot be retracted without the key even if the handle is lifted from outside. You can test this by locking the door, removing the key, and then trying to push the handle down from inside. If it moves and the bolts retract, the door is not deadlocking and the gearbox or cylinder tailpiece may need attention. If the handle is rigid and the door holds firm, it is deadlocked correctly. If you are unsure, a quick call to 020 3757 5840 and a description of the door type will let us advise you before we visit.
Are patio and French door locks something a commercial property in Wandsworth can get repaired too?
Absolutely. Alongside residential callouts our team handles commercial door locksmith work for small businesses, landlords, and managing agents across the Wandsworth area. Commercial French doors and patio sliders — common in ground-floor offices, cafes, and retail units — often have heavier-duty multipoint systems, and the consequences of a failed lock are more urgent given access, insurance, and security obligations. We carry commercial-grade gearboxes and cylinders and can work outside business hours to avoid disruption. The same up-front pricing process applies: we agree the cost before starting.
What should I do if my patio door lock has failed and I cannot secure my home tonight?
Call 020 3757 5840 straight away — we answer 24/7, every day of the year. While you wait, do not leave the property unattended if the door cannot be secured from inside. If the door can be pulled closed but the lock will not engage, you may be able to prop or wedge it temporarily, but this is not a substitute for a working lock. A trained and insured technician will be on the way usually within about 30 minutes and will carry the most common gearbox and cylinder parts to complete the repair in one visit. We serve the full Wandsworth area including Earlsfield, Tooting, Southfields, and neighbouring postcodes.