How often should I maintain a UPVC door?

Every 6 months is the standard recommendation. Lubricate the mechanism and hinges in spring and autumn. A 15-minute job twice a year prevents the majority of gearbox failures.

What oil should I use on a UPVC door lock mechanism?

Use a dedicated uPVC lubricant or 3-in-1 oil. Apply it along the mechanism track and work it in by operating the handle several times. Avoid WD-40 as a long-term lubricant — it evaporates quickly and leaves residue that attracts dust and accelerates wear.

What are the signs my UPVC door mechanism is failing?

A stiff or noticeably heavy handle, a door that requires pushing to engage the bolts, grinding sounds when lifting the handle, or bolts that only partially engage. Any of these mean the mechanism needs attention before it fails completely.

Can I fix a UPVC door mechanism myself?

Lubrication and hinge alignment are straightforward. Replacing a gearbox requires identifying the exact mechanism model, sourcing the correct part, and disassembling the door panel. If the mechanism has stopped mid-cycle — bolts partially extended — do not attempt to force it. Call a locksmith.

How much does UPVC door repair cost in London?

A gearbox replacement starts at £149 including the part. A cylinder replacement starts at £99 labour plus the cylinder. Handle replacement starts at £109 including parts. Most jobs are completed in a single visit.

Why does my UPVC door feel stiff when I lift the handle?

Either the mechanism needs lubrication, the door is misaligned so the bolts press against the keeps, or the gearbox is wearing out. Start with lubrication and an alignment check. If the stiffness persists after both, the gearbox is the issue.

Photo by PNW Production / Pexels

upvcmaintenance

UPVC Door Maintenance — How to Keep the Mechanism Working

A UPVC door mechanism needs basic maintenance every six months. Skip it long enough and the gearbox seizes. Here is what to do and how to spot the early warning signs.

James Mitchell

22 June 2026 · 6 min read

## What a UPVC door needs

A UPVC door mechanism needs two things: lubrication and alignment checks. Do both every 6 months and most mechanisms last 10–15 years without a repair call.

Skip both long enough and the gearbox seizes. At that point it is a repair, not maintenance, and it starts at £149.

Lubricating the mechanism

When you lift the handle, the gearbox drives multiple bolts into the frame — top, middle, and bottom. Those moving parts need oil.

Use a proper uPVC lubricant or 3-in-1 oil. Apply it along the full length of the mechanism through the gaps around the cylinder and handle, then lift and lower the handle several times to work it in.

Do not use WD-40 as a long-term lubricant. WD-40 is a water displacer and dries out quickly. It will help temporarily if the mechanism is stiff but it is not a substitute for oil. Using it repeatedly leaves a residue that attracts dust and speeds up wear.

Oil the hinges too. Three or four drops on each hinge, then open and close the door several times. A stiff hinge puts lateral strain on the frame and the locking points — a common cause of gearbox failure that gets blamed on the mechanism.

Checking door alignment

A UPVC door that has dropped out of alignment will not lock smoothly. The locking bolts will not engage the keeps cleanly, and the gearbox works harder with every operation.

With the door open, look at the gap between the door edge and the frame. It should be consistent all the way round — roughly 3–4mm. If the gap is wider at the top and narrower at the bottom, or vice versa, the door has sagged.

UPVC doors have adjustment screws on the hinges that allow vertical and lateral movement. A quarter-turn is usually enough to correct minor sagging. If the door is badly out of alignment, call a locksmith before forcing it into its locking points — that is how gearboxes fail.

Warning signs before the mechanism fails

These are signs that something needs attention:

- The handle feels noticeably stiffer than it used to - The door will not lock from outside without lifting the handle and pushing the door at the same time - The key turns but you have to push the door into the frame for the bolts to engage - You can hear a grinding or clicking sound when operating the handle - One or more locking points engage but others do not

Any of these means the mechanism is working harder than it should. Lubrication and alignment checks catch most issues early. If the problems persist after maintenance, the gearbox is wearing out.

What happened in Kennington

A family called because their front door lever had seized mid-morning, with a toddler inside. The mechanism had stopped mid-movement — the bolts were partially extended and the handle would not complete its travel in either direction.

We bypassed the mechanism without breaking the door. Door and frame came out intact. Total time from call to the door being open: 40 minutes.

The gearbox showed years of wear consistent with no lubrication. The follow-up repair was a gearbox replacement — £149 all in. A can of uPVC lubricant every six months would have prevented it.

The difference between worn and broken

A worn mechanism is stiff or intermittent. It still works, but you can feel it getting worse. Lubrication at this stage can extend its life by months.

A broken mechanism is one where the handle lifts but nothing moves, or the bolts engage and the door will not open from inside. The gearbox needs replacing. There is no repair that brings back a snapped drive cam or stripped gear.

The distinction matters: one is a planned maintenance cost and the other is an emergency call at whatever time the mechanism finally gives out.

When not to wait

If the door will not lock at all, do not leave it. A UPVC door held closed only by the latch can be forced with a shoulder in seconds. The multi-point bolt system is what provides structural resistance.

Call the same day. A gearbox replacement takes 45–90 minutes and the door will be secure before the engineer leaves.

Areas we cover

We carry out UPVC door repairs and maintenance checks across central London: Kennington, Lambeth, Southwark, Westminster, Kensington, Chelsea, Camden, Islington, Shoreditch, Hackney, Wandsworth, and surrounding areas. Same-day appointments are usually available.