Patio & French Door Locks

A uPVC patio sliding door typically uses a multipoint locking mechanism driven by a central gearbox. When you lift the handle, a series of hook bolts, roller cams, and mushroom-headed bolts shoot simultaneously into the keeps embedded in the frame. The weak points are predictable: the gearbox itself wears under daily use, the hooks can shear or stick, and the keeps in the frame gradually loosen as the uPVC moves through seasonal temperature changes. French doors — the hinged double-door style — follow a similar principle but add the complication of an astragal bar (the vertical strip where the two leaves meet) and the need for each leaf to lock independently before the shared multipoint mechanism engages.

The locking hardware on French doors varies considerably. Some doors use a french door knob lock or a french door lever lock set into the stile, operating a simple latch independent of the multipoint system. Others are fitted with a french door mortise lock — essentially a mortice lock body let into the door stile, sometimes called a mortise lock french door set — and on older or heavier doors you may encounter a 5 lever rebated mortice lock for french doors, which accounts for the overlap between the two door leaves. When any of these components seize, the door can become impossible to open from inside or outside. Our technicians carry gearboxes, hook bolt assemblies, euro cylinders, and mortice lock bodies to cover the range of hardware found across Bexleyheath properties.

These four terms are often used interchangeably, but they mean different things and carry different implications for cost and time. A repair means restoring an existing mechanism to working order — realigning a dropped door, lubricating and adjusting hook bolts, or replacing a single broken component within the gearbox assembly. A lock change means swapping out the cylinder (the euro cylinder that the key turns) while keeping the gearbox and handles in place; this is the right call when a key has been lost or a tenancy has ended and the landlord or letting agent needs key control restored without replacing the full mechanism. A replacement means fitting an entirely new gearbox, multipoint mechanism, or mortise lock set — necessary when the internal components have failed beyond adjustment. An installation applies when a door has no working lock at all, or where a secondary lock such as a surface-mounted patio door lock is being added for extra security.

In practice, our technicians diagnose before they quote. We will not recommend a full replacement when a repair will do the job safely and reliably, and we will not patch a mechanism that is genuinely beyond serviceable life. The factors that shape the final quote include the type and brand of mechanism, the number of locking points, whether replacement parts need to be sourced during the visit, the time of day, and travel distance to your address. We confirm an exact up-front price before any work begins, so there are no surprises on the invoice. If you are unsure whether your door needs a repair or a replacement, call 020 3757 5689 — we answer 24 hours a day — and describe what the door is doing; our team can often give you a clear steer before we even arrive.

Multipoint lock replacement on a uPVC patio or French door requires matching the existing mechanism precisely — the case dimensions, the backset, the handle height, and the hook spacing all need to align with the cutouts already in the door. Getting this wrong means cutting into the uPVC profile, which weakens the door permanently. Our technicians measure carefully and, where possible, source a direct replacement that fits without modification. Where the original manufacturer's part is no longer available, we fit a compatible unit from a reputable supplier that meets the same security standard. Euro cylinder replacement on these doors follows the same principle as on any composite or uPVC front door: we measure the existing cylinder, remove it without damaging the door furniture, and fit a new anti-snap cylinder of the correct size. Anti-snap protection matters on rear and side doors just as much as on the front — opportunist break-ins via patio and French doors are not uncommon in residential streets across Bexleyheath DA6 and the surrounding DA postcode area.

For doors fitted with a french door mortise lock or a mortise lock set within the stile, replacement involves carefully chiselling out the old body if it has seized in position, checking the mortice pocket dimensions, and fitting a correctly sized replacement — including, where the door design requires it, a 5 lever rebated mortice lock for french doors to handle the rebated meeting stile. Night latch and rim cylinder replacements are less common on patio and French doors but do arise on older properties where a surface-mounted nightlatch has been added as a secondary measure; these follow the same process as a Yale-style replacement on a front door. Across all of these lock types, our aim is damage-free removal and fitting wherever the condition of the door allows.

If a failed mechanism has left you locked out in Bexleyheath, the first sensible steps are to check whether another door or window is accessible (without taking any risk), and to see whether a spare key is held by a trusted neighbour, your letting agent, or a managing agent if you are a tenant. If none of those options apply, call 020 3757 5689. We send a technician straight away and are usually with you in around 30 minutes, though we never promise an exact time because traffic and demand vary. Our technician will verify that you have the right to access the property — standard practice that protects you as well as your neighbours — and will then work to open the door with as little disruption to the door and frame as possible. Where the mechanism has simply jammed rather than broken, we will attempt to free it before recommending replacement.

It is worth understanding how to lock French doors with lever handles correctly, because many call-outs turn out to be user error rather than a mechanical fault. On most multipoint French door systems, the passive leaf (the one that doesn't have the handle) must be locked first by operating its own top and bottom bolts before the active leaf's handle is lifted to engage the full mechanism. If you lift the active leaf handle while the passive leaf is loose, the gearbox on the active door takes all the strain and will wear prematurely. Our technicians are happy to walk you through the correct operation of your specific door as part of any visit, at no extra charge.