Locks explained
Multipoint Locks: How They Work and Why They Fail
A multipoint lock secures a uPVC or composite door at three or more points along its edge, driven by a gearbox behind the handle and locked by a euro cylinder. When it fails, the cause is usually a worn gearbox or a door that has dropped. A mechanism or gearbox job costs £85 to £300 (MLA price list; MyJobQuote).
What is a multipoint lock?
A multipoint lock is a long steel strip running down the edge of the door with a central gearbox and several locking points: hooks, rollers, mushroom cams or bolts. Lifting the handle throws them all into keeps on the frame at once, and turning the key or thumb turn then locks the gearbox so the handle cannot be pushed down. It is the standard lock on uPVC and composite doors and is found on many timber and aluminium doorsets too. The key works a separate euro cylinder, which is why a cylinder can be changed without touching the mechanism.
Which standard applies to a multipoint lock?
The grade people ask about sits mostly on the cylinder: TS 007 3 star, a 1 star cylinder with a 2 star handle, or Sold Secure SS 312 Diamond. The whole door, including frame, glazing and lock, can be tested as a doorset to PAS 24, the baseline for Secured by Design's Police Preferred Specification. Insurers usually ask for a multipoint lock with a graded cylinder on uPVC and composite doors, though wording varies. The mechanism has no consumer-facing grade of its own, so what you check is the cylinder mark and, for a new door, PAS 24.
Why does a multipoint lock stop working?
The common faults, roughly in order:
- The door has dropped. Hinges sag, the hooks miss their keeps, and you have to lift hard or push the door to lock it. That extra force strains the gearbox. - The gearbox is worn or broken. The handle feels loose, does not return level, or lifts without throwing the points. - A keep or roller has moved. One point binds and the whole strip feels stiff. - The cylinder is failing. The key catches, or turns without locking.
If the handle is getting harder to lift, a small hinge or keep adjustment early can save the gearbox later.
How do you tell what multipoint lock you have?
Open the door and look at its edge. A long faceplate with several hooks, rollers or bolts is a multipoint lock; a single bolt and latch is a sashlock. The maker's name, and sometimes a part number, is stamped on the faceplate, and it matters, because gearboxes are not all interchangeable. Measure the backset, the distance from the door edge to the centre of the cylinder, and the distance between the handle spindle and the cylinder, known as the centres. A locksmith matches those figures to a replacement gearbox or a full strip.
What does a multipoint repair cost, and when do you call a locksmith?
A gearbox repair or a replacement multipoint mechanism costs £85 to £300 (MLA price list; MyJobQuote, checked October 2026). The low end is a gearbox swap; the high end covers a full strip, an obsolete pattern, or extra work on a dropped door. If the cylinder needs changing as well, a fitted euro cylinder is £105 to £175 from the same two sources. Call before the door jams shut or open: a door that will not lock cannot be left, and a jammed gearbox on a locked door is a harder job than a stiff one.
Common questions
Why do I have to lift the handle so hard to lock my door?
Usually the door has dropped or the keeps are out of line, so the hooks drag. Adjusting the hinges or keeps often cures it. Left alone, the extra force wears out the gearbox.
Do I need a whole new mechanism or just a gearbox?
Often only the gearbox, if the strip and locking points are sound and a matching gearbox is still made. Older or discontinued patterns sometimes need a full replacement strip, which costs more.
Can the cylinder on a multipoint door be upgraded on its own?
Yes. The cylinder is a separate part. Fitting a TS 007 3 star or SS 312 Diamond cylinder is the usual upgrade, at £137 to £150 fitted (MLA price list; Checkatrade).