uPVC door repair

What the job covers

• Replacing a failed gearbox when the handle turns but the door will not lock
• Fitting a new multipoint mechanism when hooks or rollers have broken
• Adjusting the hinges on a dropped door so the hooks meet the keeps
• Replacing a drooping handle with one whose spindle and screw centres match
• Repairing the lock on a patio, French or sliding door

A uPVC or composite door locks at several points at once. Lifting the handle drives a multipoint mechanism that runs the height of the door, throwing hooks, rollers or bolts into keeps on the frame; the key then turns a euro cylinder to deadlock it. In the middle, behind the handle, sits the gearbox, the part that most often fails. When the handle turns but nothing moves, or the key will not turn, the gearbox or the mechanism has usually broken.

The commonest cause is not the lock at all. A dropped door, one that has sagged on its hinges, puts the hooks out of line with the keeps, so the handle has to be forced up. Forcing it wears the gearbox until it gives. Adjusting the hinges and keeps is often the whole repair if it is caught early. Keytek reports uPVC failures peaking twice a year, in summer heat and winter cold, as frames expand and contract.

Replacing a mechanism means matching the old one: the backset (from the door edge to the centre of the cylinder), the distance between the spindle and the cylinder, the length of the faceplate and the number of locking points. Fullex, Winkhaus, Yale, Maco and GU all make different patterns. A careful locksmith reads the markings on the faceplate and either carries the part or orders the exact one, rather than forcing a near fit. Replacing only the gearbox, where the maker allows it, costs less than the whole strip.

A handle that droops has a weak spring, and a new handle must match the spindle position and screw centres. Patio, French and sliding doors use different locks again, so say which you have when you call.

Ask for the total before work starts: parts, labour, VAT and any call-out charge. Describe the symptom exactly: the handle goes down but will not lift, the key will not turn, or the door has to be slammed. Ask whether they will adjust the door so the new part is not strained, and whether they plan to replace only the gearbox or the full mechanism, and why. Ask whose parts they fit and what guarantee comes with them. If the door is locked shut, ask how they will open it and whether the door or frame could be damaged.

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