uPVC Door Maintenance — What to Do Before It Stops Working
Most uPVC door failures are preventable. Simple maintenance guide — lubrication, adjustments, and the early signs that the mechanism needs attention.
Most uPVC door failures aren't sudden. They're a gradual stiffening, a slight resistance here and there, a handle that needs a bit more force than last year. By the time the door stops working entirely, it's usually been telling you for months. Here's what to do before you get there.
In short
- Lubricate with PTFE spray once a year — not WD-40
- Adjust hinges if the door drops or stiffens
- Check the weather seals and keep them clean
- Stiff handle or handle goes up/down but nothing locks = time to call a locksmith
The golden rule: use PTFE, not WD-40
WD-40 stands for Water Displacement, 40th formula. It's a solvent and a water displacer. It's excellent for loosening seized nuts, not for lubricating door mechanisms. What it does to a lock cylinder over time is strip out any actual lubricant, then attract dust, which builds up into a paste inside the mechanism. Two years of WD-40 on a lock costs more to fix than two decades of PTFE.
PTFE-based dry lubricant sprays are widely available from hardware shops. Spray into the cylinder, around the hinges, and into the mechanism through any accessible slot in the frame. Do this once a year, ideally at the start of summer before the heat makes everything expand.
Hinge adjustment
uPVC doors drop with age — the hinges compress over years of use, the door sags fractionally, and it starts to drag on the sill or press unevenly against the frame. This creates stiffness and eventually prevents the multi-point locks from engaging properly.
Modern uPVC hinges have adjustment screws. There are usually two:
- Compression adjustment — how hard the door presses against the seal (inward/outward)
- Lateral adjustment — left/right position of the door in the frame
A quarter-turn of each makes a visible difference. Adjust slowly, check the gap around the door after each adjustment, and test the lock engages smoothly. If the gaps are uneven — wider at the bottom than the top, or vice versa — that's hinge drop. Adjust the lateral screw on the lower hinge to correct it.
If you've lost the hex key size, it's usually 4mm or 5mm.
Weather seal maintenance
The rubber seal around the door frame takes years of compression, UV exposure, and temperature cycling. It becomes brittle, cracked, and eventually stops sealing properly. Doors with failed seals let in draughts, are noisier in wind, and the door often fits less snugly — which makes it work harder to lock.
Once a year: clean the seal with warm soapy water, dry it, and apply a silicone-based rubber conditioner. This slows UV degradation significantly. If the seal has hardened, cracked, or come away from the frame in sections, replacement is a half-hour job.
The early warning signs
In order of urgency:
- Slight stiffness in the handle lift — lubricate and check hinge adjustment
- Door catching on the sill — hinge drop, adjust now
- Handle noticeably harder than last year — mechanism starting to wear; lubricate, adjust, monitor
- Key stiff in the cylinder — lubricate the cylinder specifically; if it doesn't improve, the cylinder may be wearing
- Handle lifts but only some locks engage — mechanism failure starting; call a locksmith
- Handle lifts but nothing engages — gearbox has failed; door won't lock
Signs 1–4 are maintenance. Signs 5–6 are repair. The difference in cost between catching it at 3 versus arriving at 6 is approximately £300.
What not to do
- Don't force a stiff handle. The handle is connected to the mechanism. Forcing it bends the cam, damages the rollers, and turns a £40 call-out into a £400 mechanism replacement.
- Don't ignore a door that drags on closing. That friction is being transferred into the locking mechanism every time you shut the door.
- Don't assume stiffness in winter is just the cold. Thermal expansion does affect uPVC, but a well-adjusted door handles it. Consistent stiffness is an adjustment problem, not just weather.
Sign-off
If your uPVC door has gone from maintenance territory to repair territory, call 020 3780 8827. Most mechanism failures in Barnet are diagnosed on site and repaired the same day where parts are available.
Frequently asked questions
How often should I oil a uPVC door lock?
Once a year at minimum. Use a PTFE-based dry lubricant spray on the lock cylinder, hinges, and any moving parts in the frame. Do not use WD-40 — it is a water displacer and solvent, not a lubricant, and it attracts dust which gums up the mechanism over time.
My uPVC door is stiff but still works — should I worry?
Yes, a bit. Stiffness usually means the door has dropped slightly or the mechanism is starting to wear. Left alone, stiffness becomes a stuck door. Hinge adjustment and lubrication now costs much less than a mechanism replacement later.
The handle goes up and down but the door won't lock — what's wrong?
The gearbox (multipoint mechanism) has failed. This is a mechanical failure, not a lock issue. The mechanism needs to be replaced. See the uPVC door repair page for pricing.
Can I adjust the hinges on a uPVC door myself?
Yes. uPVC door hinges usually have two adjustment screws — one for lateral (left-right) adjustment and one for compression (how hard the door presses against the seal). A cross-head screwdriver is usually enough. Adjust in small increments.
What's the lifespan of a uPVC door mechanism?
10–20 years with maintenance, significantly less without. The gearbox is the component that fails most often, typically from wear on the cams and rollers. Heat in summer and cold in winter both accelerate wear if the mechanism isn't lubricated.
Locked out? Need a locksmith now?
Call now and speak to John directly — no call centre, no script. You'll know the price before he's on his way.