uPVC Door Repair vs Replace Cost | The Ten-Year Maths
Full cost breakdown: repairing a uPVC door gearbox and cylinder twice a decade vs replacing the whole door. Real figures for Richmond homeowners.
A full uPVC door replacement in the TW9 to TW10 area will set you back somewhere between £800 and £1,800 fitted. A gearbox service and cylinder swap costs roughly £120 to £200. Do that twice over ten years and you're still under £400. The maths isn't subtle.
Yet every week someone calls us convinced they need a new door when the mechanism just needs a new multipoint gearbox and a decent cylinder. Sometimes the reverse is true: they've patched a door that's beyond saving and wasted money twice. So let's go through it properly.
What Actually Goes Wrong with a uPVC Door
Most faults come down to three things.
- The multipoint gearbox wears out. The hooks, rollers and deadbolt all run off one mechanism, and after years of use the steel strips and cams inside start to slip. The door lifts the handle but nothing locks.
- The cylinder gets loose or starts resisting the key. If it's a standard euro cylinder, it's also a pick-and-snap target.
- The frame or sash warps slightly. uPVC moves with temperature. A door that locks fine in January may catch in August.
The first two are repairs. The third depends on how bad the warp is.
The Ten-Year Cost Table
| Scenario | Year 1 | Year 5 | Year 10 | Ten-Year Total |
|---|---|---|---|---|
| Replace the whole door | £800 to £1,800 | £0 | £0 | £800 to £1,800 |
| Replace door + cylinder upgrade at fit | £950 to £2,000 | £0 | £0 | £950 to £2,000 |
| Gearbox replacement + cylinder swap now | £120 to £200 | £120 to £180 (cylinder service or swap) | £120 to £200 (gearbox if needed) | £360 to £580 |
| Gearbox only, cheap cylinder left in | £80 to £140 | £80 to £140 | £80 to £140 | £240 to £420 |
The cheapest column is not the best column. Leaving a standard euro cylinder in a uPVC door in 2025 is a real problem: snapping attacks take about ten seconds with a cheap tool you can buy on the internet. A Ultion or Avocet ABS TS007 3-star cylinder costs £40 to £70 on top of the gearbox job. That's the row to be on.
What Drives the Door Replacement Cost Up
Glass specification is the biggest variable. A plain white uPVC door with standard double glazing in a flat in North Sheen costs less than a composite-effect door with a decorative leaded panel on Richmond Hill. If you want PAS24 certification for insurance purposes, or the frame needs rebuilding because the original fit was poor, that pushes you toward the higher end.
Labour in SW London is not cheap either. Expect to pay more here than a national average quote suggests.
When Replacing Is Actually the Right Call
Be honest about the frame. If the uPVC has gone brittle, cracked at the corners, or the steel reinforcement inside has rusted and buckled the profile, no gearbox in the world fixes that. Same if the threshold has dropped so far that the door clears the ground by 15mm in the middle but drags at the sides.
A door over 20 years old with a rotten frame, broken double-glazing seal and a sprung sash is a replace job. Don't throw £160 at a gearbox in a door that'll need replacing in 18 months anyway.
A door that's 8 to 12 years old, structurally sound, with a failed gearbox? Almost always worth repairing.
How to Spend the Money Sensibly
First call: get the mechanism diagnosed before you agree to anything. A locksmith should be able to tell you within five minutes whether the fault is the gearbox, the cylinder, an alignment issue or something structural. If anyone jumps straight to 'you need a new door' without trying the handle a few times and checking the keep alignment, be sceptical.
If you're repairing, do the cylinder at the same time. Brands worth fitting: Ultion TS007 3-star, Avocet ABS, Mul-T-Lock MT5+. All meet SS312 Diamond standard. All are significantly harder to snap than the cylinder that probably came with the door.
If you do replace the door, make sure the new cylinder isn't the builder-grade chrome euro that comes in the box. Swap it out on day one.
For most occupied homes in Ham, Petersham, East Sheen or St Margarets, a decent repair adds five or more years to a functioning door. The savings over replacement are real. The upgrade cylinder pays for itself the first time someone tries the door who shouldn't.
uPVC or composite door repair
What is the door doing? Tick the closest, the engineer confirms on site.
A guide, not a quote. We give you the actual labour rate, an estimate on parts and the VAT on the call, then fix the price before any work starts. No anti-social hours surcharge.
If you're in the Richmond or TW postcode area and not sure which camp your door falls into, Rapid Response covers the area with an average arrival under 30 minutes. We'll tell you on the call what's likely involved and give you a price before we start.
Tom Bradley, Commercial and landlord locksmith
Tom looks after the shops, offices, HMOs and landlords. He thinks in terms of what a thing costs a business over a year, not just on the day, and he has fitted enough master suites to know when one is overkill.
Need a locksmith in Richmond?
We answer the phone day or night. Quote on the call, fixed at the door.
020 3376 9314