UPVC doors are the most common type of external door in the UK, and virtually all of them use multipoint locking systems. Understanding how these systems work — and what to do when they go wrong — is essential knowledge for any UK homeowner.

How UPVC Multipoint Locks Work

Unlike a traditional single-point lock that only secures the door at one point, a multipoint locking system engages at multiple points along the door frame simultaneously. When you lift the handle and turn the key, a series of hooks, bolts and rollers extend from the door into keeps in the frame, creating a much more secure seal than a single-point lock.

The heart of the system is the gearbox — a mechanical unit inside the door that translates the movement of the handle into the extension and retraction of the locking points. The euro cylinder (the part you insert the key into) operates the gearbox to lock and unlock the door.

Common UPVC Door Lock Problems

Dropped handle: The handle drops down and won't spring back up — usually caused by a worn or broken gearbox
Door won't lock: The key turns but the door doesn't lock — misalignment or worn gearbox
Stiff key: The key is difficult to turn — worn cylinder or misaligned door
Door won't close properly: The door has dropped or the frame has moved — requires adjustment
Lock snapping: The cylinder has been snapped by a burglar — requires immediate replacement
Broken handle: The handle has broken off — requires replacement

Repairing vs Replacing

Many UPVC door lock problems can be repaired rather than requiring a full door replacement. Keys4U carries gearboxes, cylinders and handles for all major UPVC door brands and can usually carry out repairs on the same visit. However, if the door itself is damaged or severely misaligned, a new door may be the most cost-effective solution.

Upgrading Your UPVC Door Security

The most important security upgrade for a UPVC door is replacing the standard euro cylinder with an anti-snap, anti-pick, anti-drill cylinder. Standard cylinders are vulnerable to lock snapping — the most common burglary technique for UPVC doors. An anti-snap cylinder can be fitted in under 30 minutes and costs from around £80 including fitting.

Look for cylinders rated TS007 3-star or Sold Secure Diamond — these are the highest security ratings available and are accepted by all major home insurers.

Measuring Your Cylinder

If you need to replace your cylinder, you'll need to measure it correctly. Measure from the centre of the fixing screw to each end of the cylinder. For example, a 35/45 cylinder measures 35mm on the inside and 45mm on the outside. Getting the measurement wrong means the cylinder won't fit correctly.

Keys4U locksmiths carry a wide range of cylinder sizes and can measure and fit the correct cylinder on the same visit. For UPVC door lock replacement across the UK, call us today.