Sliding patio doors and French doors are the most common doors onto a garden or patio, and because they sit at the back of a property, out of sight, they are a favourite target for forced entry. Both are sensitive to dropping and alignment, and both are almost always repairable rather than in need of replacement. The good news is that the faults that leave these doors insecure — a dropped leaf, a worn roller, a tired shootbolt or a basic cylinder — are the everyday work of a locksmith, not a job for a window company, and they are almost always fixed in a single visit. We diagnose the actual fault, tell you honestly whether it is a repair or an upgrade, and give you a fixed price before any work starts, with no call-out fee.
Sliding patio door locks
Sliding patio doors are held by hook bolts that pull into the frame, and their biggest weakness is lifting: a poorly secured sliding door can be levered up and off its track. We fit and adjust anti-lift devices and hook bolts, replace worn patio locks and the rollers that have let the door drop, and realign the sliding panel so it runs and locks smoothly. If your patio door has started to catch, scrape or lift in its frame, that is the warning sign to deal with before it stops locking altogether.
French door locks
French doors have a “first-locking” or slave leaf held by top-and-bottom shootbolts (the espagnolette), and a master leaf with a euro cylinder. The faults we see most are a leaf that has dropped so the shootbolts no longer line up with their keeps, worn or seized shootbolt mechanisms, and tired cylinders. We realign the leaves, replace the shootbolt and espagnolette mechanisms, and upgrade to correctly sized anti-snap euro cylinders so the doors lock firmly top and bottom again.
Worn rollers and dropped doors
Both door types ride on rollers or hinges that wear over time, and once the door drops even a few millimetres the locking points stop lining up — so it gets harder to lock and eventually won’t. Catching it early means a roller or hinge adjustment and a keep reposition rather than a failed mechanism and a door you can’t secure.
Security upgrades
Where a euro cylinder is fitted we upgrade to an anti-snap, TS007 3-star cylinder cut to the exact length — an over-long cylinder that protrudes past the handle is one of the easiest things to attack. On sliding doors we add or adjust anti-lift hardware, and on both we reinforce the keeps so the bolts have something solid to bite into. Because patio and French doors are a common back-of-house entry point, these upgrades make a real difference. Many of the anti-snap cylinders we fit, such as Ultion, also carry a manufacturer’s guarantee against snapping and come with key control, so replacement keys can only be cut with your authority — useful on a door that opens onto a garden that neighbours or passers-by can see into. Where a matching cylinder is on your front and back doors we can key them alike, so a single key runs the whole house. And because most of this is a straightforward retrofit — measuring the existing lock and swapping the cylinder or shootbolt — it is usually done in one visit, at a fraction of the cost of a new door.
