What Is a Multipoint Lock and How Does It Work?
The Lock Behind Almost Every uPVC and Composite Door
If your front door is uPVC or composite - as most British front doors installed in the last 25 years are - it almost certainly has a multipoint lock. You use it every day without thinking about it: lift the handle, turn the key, and the door is secured. But what is actually happening inside the door when you do that is more complex than a traditional single-point lock, and understanding how it works helps you recognise problems before they become emergencies.
How a Multipoint Lock Works
A multipoint lock secures the door at three, five, or sometimes seven points along its edge, rather than at a single point like a traditional mortice deadlock. When you lift the handle, several components engage simultaneously:
- Hooks - metal hooks that swing out from the door edge and grip into keeps (metal plates) fitted in the door frame. Most doors have two hooks, positioned above and below the main lock body.
- Rollers or mushrooms - compression bolts that press into the frame to pull the door tight against the weatherseal. These improve both security and draught-proofing.
- Central latch and deadbolt - the main lock body, operated by the euro cylinder, which contains both a sprung latch (for day-to-day closing) and a deadbolt (for full locking).
The sequence is: push the door closed (the latch catches), lift the handle (hooks and rollers engage), turn the key (the deadbolt throws and everything locks in place).
This distributed locking is significantly more secure than a single deadbolt because force applied to any one point of the door is resisted by all the other locking points simultaneously.
Types of Multipoint Lock
There are several gearbox (the main lock body) configurations used in UK doors:
By Locking Point Type
- Hook locks - the most common on modern doors. Hooks provide strong resistance to the door being forced outward from the frame.
- Deadbolt locks - use traditional deadbolts at multiple points. Less common on modern uPVC doors but found on some composite doors and older installations.
- Roller locks - primarily for draught-proofing rather than security. Rollers pull the door tight but do not provide the same resistance to forced entry as hooks.
Most modern multipoint locks use a combination - hooks for security and rollers for compression.
By Backset and Centres
Multipoint locks are not one-size-fits-all. Two key measurements define which gearbox fits your door:
- Backset - the distance from the edge of the door to the centre of the keyhole. Common UK backsets are 35mm and 45mm.
- Centres (PZ) - the distance from the centre of the keyhole to the centre of the handle spindle. The standard in the UK is 92mm (sometimes called PZ92), but 62mm and 72mm also exist.
These measurements matter when replacing a multipoint gearbox - the replacement must match the original, or the door will not lock correctly.
The Euro Cylinder: The Weak Link
The multipoint lock mechanism itself is robust. The weak point, in most cases, is the euro cylinder that operates it. A standard euro cylinder can be snapped in seconds using basic tools, and once it is broken, the entire multipoint system can be unlocked.
This is why upgrading to an anti-snap euro cylinder is the single most effective security improvement for a uPVC or composite door. The multipoint mechanism stays the same - you are only replacing the cylinder. For more detail, see our guide on lock snapping and how to prevent it.
Common Multipoint Lock Problems
The Handle Will Not Lift
The most common complaint. Causes include:
- Misaligned door - the door has dropped slightly on its hinges, so the hooks and rollers no longer line up with the keeps in the frame. This is often seasonal - doors expand in warm weather and contract in cold.
- Worn gearbox - the internal mechanism that translates handle movement into hook engagement has worn. This is a mechanical wear issue that worsens over time.
- Broken gearbox spring - the spring that returns the handle to the down position has snapped, preventing the mechanism from cycling correctly.
The Door Locks but Feels Loose
If the door locks but there is noticeable movement or draughts, the rollers or mushroom bolts may be worn and no longer pulling the door tight against the frame. Adjusting or replacing the keeps in the frame can often resolve this.
The Key Turns but the Deadbolt Does Not Throw
This usually indicates a problem with the connection between the euro cylinder cam and the gearbox. Either the cylinder is the wrong length (the cam does not reach the gearbox mechanism), or the gearbox itself has a fault.
The Door Slams Shut but Will Not Latch
The sprung latch is sticking or the latch keep in the frame is misaligned. This can sometimes be resolved by adjusting the keep, but a sticking latch often indicates internal corrosion or wear that requires gearbox replacement.
Repair or Replace?
When to Repair
- Door misalignment - a locksmith can adjust hinges and keeps to restore alignment
- Worn keeps - the frame-side hardware can be replaced independently of the lock
- Stiff operation due to lack of lubrication - silicone spray on the moving parts can restore smooth operation
When to Replace
- Broken gearbox - if the internal mechanism has failed, the gearbox needs replacing. Individual gearbox components are not available as spare parts.
- Multiple symptoms - if the door is stiff, the handle is loose, and the locking is inconsistent, the gearbox is usually the cause
- After a break-in attempt - even if the mechanism still works, it may have been weakened
Gearbox replacement is a job for a professional locksmith. The door panel needs to be partially disassembled to access and remove the old gearbox, and the replacement must match the exact specifications. Our uPVC locksmith service covers multipoint lock repair and replacement across London.
How Much Does Multipoint Lock Work Cost?
| Service | Typical Cost |
|---|---|
| Door realignment (hinge adjustment) | From £69 |
| Euro cylinder replacement (anti-snap) | From £69 labour |
| Multipoint gearbox replacement | From £99 labour |
| Keep adjustment or replacement | From £45 |
Parts are charged separately. For full pricing, see our locksmith price list.
City Locksmith London
We work with multipoint locks every day - replacements, repairs, and upgrades. If your door is stiff, your handle is not lifting properly, or you want to upgrade the cylinder, our uPVC locksmith service covers all of it. Contact us for a quote.