Diagnosis guide

Front Door Won't Lock

A door that needs lifting, shoving or a second attempt to lock is warning you before the gearbox fails completely.

Most people landing here want one thing: to get the door secure tonight and know whether it's the cylinder, the gearbox or the alignment. That's what this page answers — no scare tactics, no automatic upsell to a full replacement.

Get it looked at 07375 533723

Composite front door with multi-point locking — a front door that won't lock put right by Rosac

What you'll notice first

you have to lift the handle hard, or lean on the door, before the key will turn
the handle goes up but the key spins with no resistance
the door locks from inside but not from the outside
a grinding or clicking noise from inside the door as the handle rises

What actually causes it

1the multi-point gearbox has worn or a cam has sheared inside the mechanism
2the slab has dropped on its hinges so the hooks no longer line up with the keeps
3the euro cylinder is worn and the key no longer picks up the cam cleanly
4seasonal movement — a composite slab expands slightly in a hot spell and binds on the frame
5the keeps have never been adjusted since the original fit and have worked loose

Your realistic options

Alignment and keep adjustment

Hinges packed and toe-and-heeled, keeps repositioned so the hooks drop into the centre of the strike. Often the entire fix and it takes under an hour.

Gearbox or cylinder replacement

A failed multi-point gearbox is a stocked part on most common systems. Cylinders we replace with a snap-secure, anti-bump TS007 3-star unit rather than like-for-like.

New door

Worth it when the slab itself has delaminated or bowed, when the frame is out of square in the opening, or when the door is old enough that the mechanism is obsolete.

Repair or replace — our honest view

Nine times out of ten a door that won't lock is an alignment or mechanism issue, not a dead door, and the sensible route is to fix the mechanism. Replacement becomes the right answer when the slab has physically distorted, the frame has moved with the opening, or the security spec was never adequate in the first place.

What we check on survey

we check the gap line down the lock side — an uneven taper means the slab has dropped
we lift the handle with the door open to see whether the mechanism itself throws cleanly
we identify the gearbox by centre distance and backset so the right part is ordered first time
we check the cylinder standard, because a lot of original cylinders are snappable

How it's priced

Adjustment is a short visit. A gearbox or high-security cylinder is the part plus fitting. A new composite door is a different scale of spend and we'd only quote it once the repair route has genuinely been ruled out.

How urgent is it? Treat this as urgent. A door that only locks on the third attempt is a door that will eventually not lock at all, usually on the way out to work — and an unlockable front door is both a security problem and an insurance problem.

Stopping it coming back

lubricate the mechanism and hinges twice a year — most gearbox failures are dry-running failures
never force the handle when it feels stiff; that's what shears the cam
get the alignment corrected as soon as you start lifting the door to lock it

Front Door Won't Lock — questions we get asked

Can you fix the lock without replacing the door?

Almost always. Multi-point gearboxes are replaceable parts, and most locking faults are actually alignment faults that need no new parts at all.

The key turns but nothing happens — what is that?

Usually a failed cylinder cam or a sheared gearbox drive. The handle is still lifting the hooks, but the key has lost its connection to the mechanism.

Is it worth upgrading the cylinder at the same time?

Yes. If we're taking the cylinder out anyway, moving to a 3-star anti-snap unit costs very little on top and closes the most common forced-entry route on uPVC and composite doors.