Patio & French Door Locks
Patio sliders and French doors are among the most common weak points on homes across Erith — from the terraced streets off Bexley Road to the newer riverside developments near the town centre. The multipoint locking systems fitted to uPVC patio and French doors do an excellent job when they are working correctly, but the hooks, rollers, and gearboxes inside the door slab take daily stress and eventually wear out, misalign, or fail entirely. When that happens, the door either will not open from inside, will not lock at all, or leaves you with a latch that feels sloppy and insecure — none of which is acceptable on a rear garden access point.
Open 24 hours, 7 days a week · Fully insured
“Erith Locksmiths is a fully insured, mobile locksmith service operating 24 hours a day, every day of the year — evenings, weekends, and bank holidays included. Our trained technicians come directly to your property, assess the door on the spot, and carry a wide range of replacement gearboxes, cylinders, handles, and multipoint lock cassettes in the van so that most repairs are completed in a single visit. We cover Erith and the surrounding areas, including Belvedere, Thamesmead, Abbey Wood, and Slade Green, and we always confirm an exact up-front price on the phone before anyone sets off — so there are no surprises when the job is done.
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 Erith, 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.
Repairing Patio and French Door Locks: What Usually Goes Wrong
The locking mechanism on a uPVC patio slider or a set of French doors is not a single lock — it is a multipoint system that engages two, three, or more hooks or bolts simultaneously when you lift the handle and turn the key. That complexity is what makes them secure, but it also means there are more components that can wear out. The most frequent faults we attend in the Erith area are a stiff or broken gearbox (the internal mechanism that drives the hooks when the handle is lifted), snapped or bent hooks that no longer engage the keep plate in the frame, a euro cylinder that has become difficult to turn or will not release, and misalignment caused by the door dropping on its hinges over time — which puts the hooks out of line with the keeps and places enormous strain on the gearbox every time the door is locked.
On French doors specifically, the meeting stile — the vertical edge where the two leaves come together — takes additional punishment because it has to align precisely for the locks on both leaves to engage. French door lever lock problems are particularly common here: the lever handle spindle shears, the rose works loose, or the latch bolt retracts but the multipoint hooks do not follow because the gearbox has seized. We also regularly replace worn french door knob lock sets on older uPVC French doors where a knob-operated gearbox was fitted originally; these are often upgraded to a lever-operated multipoint at the same time for easier day-to-day use. If the fault is a broken or draughty seal around a patio slider, that is worth mentioning when you call, as door alignment and lock function are closely linked.
French Door Mortise Locks and Multipoint Systems Explained
Homeowners sometimes ask whether their French doors use a mortise lock. Some older timber French doors do indeed use a french door mortise lock — typically a 5 lever rebated mortice lock for french doors, which is a mortise lock set designed with a rebated faceplate so the two lock bodies on each leaf mesh neatly at the meeting stile when the doors are closed. This type of mortise lock french door setup is still common on hardwood French doors fitted before the widespread adoption of uPVC, and it can be repaired or replaced like any standard mortice deadlock. Modern uPVC French doors, however, almost always use a surface-mounted or cassette-style multipoint lock with a euro cylinder rather than a traditional door locks mortise lock arrangement — the two look very different but serve the same purpose.
If you are unsure which system your French doors have, our technicians will identify it on arrival. For timber doors needing a mortise lock for french doors, we carry a selection of rebated mortice lock sets and can fit a french door mortise lock set that meets current security standards. For uPVC multipoint systems, we stock gearboxes from several common manufacturers so we can usually match the existing lock cassette by measuring the spindle distance, the backset, and the hook spacing — no need for you to know the brand or model number before you call.
Locked Out in Belvedere or Erith? Our Emergency Response for Patio and French Doors
A failed patio or French door lock can leave you locked outside in your garden — a situation that feels less urgent than a front-door lockout but becomes a real problem after dark or in poor weather. If you are locked out in Belvedere, Erith, or anywhere in the surrounding postcode districts, call us on 020 3757 5599 and we will send a technician straight away; we are usually with you in about 30 minutes. As a 24 hour locksmith Belvedere residents and Erith homeowners rely on, we respond to these calls at any time — including late evenings and bank holidays.
Before you call, it is worth checking whether a window is on the latch or whether a neighbour holds a spare key — not because you should attempt to force anything, but because a quick check around the property occasionally reveals a simpler solution. Do not attempt to force a patio slider or French door yourself: the aluminium or uPVC frames dent and crack easily, the glass panels are costly to replace, and forcing the lock mechanism can cause secondary damage that makes the subsequent repair significantly more involved. Our trained technicians use non-destructive entry techniques wherever possible, preserving the door and frame and keeping the job straightforward. If the lock or gearbox is beyond saving, we will explain that clearly and proceed with a replacement only after you have agreed to the quoted price. As a mobile emergency locksmith Belvedere and Erith service, we carry out upvc door lock repair Belvedere calls regularly and keep common parts stocked in the van.
Replacement, Repair, or Upgrade — Choosing the Right Fix for Your Door
Understanding which service you actually need saves time and avoids unnecessary expenditure. Here is a plain guide to the four terms we use most often. A repair means fixing a component that has failed — replacing a broken gearbox spring, re-hooking a dislodged roller on a patio slider, or adjusting hinge positions to realign the door so the multipoint engages cleanly. A replacement means swapping out a whole unit — a new gearbox cassette, a new euro cylinder, or a new set of handles — because the existing component is worn beyond adjustment. An installation means fitting a lock system to a door that did not previously have one, or adding a secondary lock to a door that only had a single-point latch. A lock change means removing the existing cylinder or lock body and fitting a new one — typically done after a break-in attempt, after moving into a new property, or after keys have been lost. We provide all four services on uPVC patio sliders and French doors, and door lock replacement Belvedere and Erith calls make up a significant part of our daily workload.
The price you pay depends on several factors: the type and size of the gearbox or cylinder required, whether parts need to be ordered or are available on the van, the time of day (evening and weekend call-outs are priced differently to standard daytime visits), and the travel distance from our operative's location at the time of your call. We will always confirm the exact price with you over the phone before we set off, and we will not begin any work until you have agreed to it. There is a call-out charge, and this is explained clearly upfront — you will never be presented with an unexpected bill at the end of the job. For anything more complex — such as a lock change Belvedere landlord or letting agent needs across multiple properties — we can discuss the scope of work and quote accordingly before the visit.
Keeping Patio and French Door Locks in Good Condition
The single most effective thing you can do to extend the life of a uPVC multipoint lock is to lubricate the mechanism twice a year using a dry PTFE spray — not WD-40 or oil-based products, which attract grit and cause the gearbox to seize over time. Apply the spray to the hooks, the keeps, and the cylinder plug while working the handle through its range of movement. Check that the door sits squarely in the frame by looking at the gap around the perimeter: if the gap is uneven, the hinges may need adjustment, which is a straightforward task for a skilled locksmith but, if left unattended, will eventually destroy the gearbox. On patio sliders, keep the bottom track clear of grit and debris; a clogged track forces the roller carriage to work harder and accelerates wear on both the rollers and the locking mechanism above.
If your French doors are facing the garden and exposed to wind and rain — as many Erith properties are, particularly those near the marshes or the riverside — check the weather seals annually and replace them when they compress flat. A good seal keeps the door closing consistently against the frame, which in turn means the multipoint hooks engage with less effort and less wear. If you notice the handle becoming stiffer to lift, or if the key feels gritty in the cylinder, those are early-warning signs that call for a service visit rather than waiting for a full failure. Calling us at that stage — rather than waiting until the lock fails at 10pm on a Sunday — usually means a quicker, simpler, and less involved job. Call 020 3757 5599 any time — we answer 24/7 and are happy to advise even if you are not sure yet whether a visit is needed.
Frequently asked questions
How do I lock French doors that have lever handles rather than a knob?
On most uPVC French doors fitted with lever handles, locking the door correctly is a two-step process. First, lift the lever handle upward — this draws all the multipoint hooks into their keeps along the frame and the meeting stile simultaneously. Then insert your key into the euro cylinder and turn it to deadlock the mechanism in the engaged position. If you do not turn the key after lifting the handle, the door is held shut by the hooks but is not deadlocked, meaning the hooks can be retracted if the handle is worked from outside. Some doors have a lever-lock arrangement where turning the key both engages and deadlocks in one movement — if you are unsure how your particular door should be operated, our technicians can demonstrate the correct sequence during any visit and check that the mechanism is functioning as designed.
My patio door handle lifts but the hooks do not engage — is that the gearbox or the cylinder?
In almost every case, that symptom points to the gearbox rather than the cylinder. The gearbox is the internal cassette that converts the rotational movement of the handle spindle into the linear movement that pushes the hooks out. When a gearbox fails — usually through wear on the cam or a broken spring — the handle moves freely but nothing happens inside the door. The cylinder, by contrast, is only responsible for deadlocking the hooks once they are already engaged. Our technicians carry a range of replacement gearbox cassettes and can usually identify and fit the correct one on the same visit. If the hooks themselves are bent or the keeps in the frame are damaged, those will also need attention, but the gearbox is the most common single cause of this fault.
Can you replace a mortise lock on older timber French doors in the Erith area?
Yes. We carry a selection of rebated mortice lock sets suitable for timber French doors, including five-lever versions that meet current insurer expectations. A five lever rebated mortice lock for French doors has a specially shaped faceplate that accommodates the overlapping rebate where the two door leaves meet, so both lock bodies sit flush and the bolt shoots correctly into the striking plate on the frame. If your existing lock is worn, damaged after a break-in attempt, or simply dated, we can replace it with a modern equivalent during a single visit. We will measure the existing lock before sourcing the replacement to ensure the new set fits the existing mortise pocket without requiring frame modification where possible.
What factors affect the price of a patio or French door lock repair?
Several things influence the final quote. The type of gearbox or cylinder required is the biggest variable — a standard cassette gearbox differs in cost from a bespoke or less common profile. The time of day matters too: call-outs during evenings, weekends, and bank holidays are priced differently to standard daytime visits. Travel distance from our operative's location at the time of your call is factored in, as is whether the parts needed are on the van or have to be sourced. We always confirm the exact price with you over the phone before setting off, and we will not begin work until you have agreed to it. There are no hidden additions at the end of the job — the price agreed at the outset is the price you pay.
Is it safe to try to force open a stuck patio slider myself while waiting for a locksmith?
We would strongly advise against it. uPVC patio sliders are built around a relatively thin aluminium chassis inside a PVC casing — both materials deform under lateral force in ways that are expensive to repair and sometimes irreversible without replacing the whole door slab or frame section. Beyond the structural risk, the glass panels in the door are under a degree of stress from the frame, and forcing the door can cause the glass to crack or shatter. The practical steps worth taking while you wait are checking whether a window is on the latch, confirming whether a neighbour or family member holds a spare key, and ensuring you are in a safe and sheltered spot. Our team will be with you as quickly as possible — usually around 30 minutes — and will use non-destructive entry methods wherever the situation allows.
Do you work on commercial premises as well as homes?
Yes. As a commercial door locksmith service we attend shops, offices, and light commercial premises across the Erith and Belvedere area, not just residential properties. The multipoint lock systems used on uPVC and aluminium-framed commercial French and patio doors are broadly similar in principle to residential versions, though the gearboxes and cylinders are often heavier-duty and the keeps are set into steel frames rather than uPVC. We carry parts suited to both residential and commercial door configurations and can advise on upgrading to a higher-security cylinder profile if the existing installation is not adequate for a commercial setting. Call 020 3757 5599 at any time — we answer 24/7 for both residential and commercial enquiries.
Locked out or need a lock fixed? We are on the way.
Open 24 hours, 7 days a week · Insured, background-checked technicians · Up-front pricing
020 3757 5599