Quick answer
Most composite door problems — locks, hinges, seals, glass, handles and thresholds — are repairable, typically costing between £75 and £320 depending on the issue. Full replacement is only usually necessary for extensive timber-core water damage or a frame that's structurally beyond re-fixing, so it's always worth getting a repair assessed before assuming replacement is the only option.
Overview
The vast majority of composite door problems - locks, hinges, seals, glass, handles, thresholds - are repairable. Full replacement is only needed for extensive slab damage or catastrophic frame failure.
Symptoms
- Any door problem.
Common causes
- Age, wear, damage.
The repair-first approach
A surprising number of homeowners assume that any significant problem with a composite door means starting again with a new one. In our experience, that's rarely true — the slab, frame and hardware are all individually repairable or replaceable components, and it's unusual for enough of them to fail simultaneously that a full replacement genuinely makes more sense than a targeted repair.
This matters financially: a £150–£250 repair extending a door's useful life by another five to ten years is a far better outcome than a £1,395+ replacement triggered by something that didn't actually need it. We always assess with repair as the default assumption and only recommend replacement where the numbers or the condition genuinely point that way.
The most common repairs, by frequency
Alignment and hinge adjustment accounts for roughly a third of our repair call-outs — a door that's begun to drop, catch, or need extra effort to close is almost always a hinge adjustment or replacement, not a sign of anything more serious. Lock and cylinder problems make up another significant share, ranging from a simple lubrication and adjustment through to full multi-point mechanism replacement where the gearbox itself has failed.
Seal replacement, handle and letterbox hardware, and glass unit repairs make up most of the remainder. Each of these is a component-level fix — the door doesn't need to come off its hinges for most of them, and several can be completed in under an hour.
- Alignment/hinge adjustment — most common repair
- Lock and multi-point mechanism repair or replacement
- Seal (weatherstrip) replacement
- Handle, letterbox and hardware replacement
- Glazed unit repair (misting, cracked glass)
- Threshold and cill repair
How we diagnose before quoting
Every repair starts with an actual diagnosis rather than a guess from a description over the phone. Symptoms often overlap — a door that's 'hard to lock' could be a hinge, a keep alignment issue, a gearbox fault, or frame movement, and each has a different fix and cost. A short on-site assessment identifies the real cause before any parts are ordered or work quoted, which avoids paying for the wrong fix.
This is particularly important on older doors where more than one issue may be present simultaneously — for example, a worn hinge causing enough drop that the lock also struggles to engage. Fixing only the lock symptom without addressing the underlying hinge wear would mean the same call-out again within months.
What genuinely can't be repaired
There are a small number of situations where repair isn't the sensible route. Extensive water damage that's reached the timber core of the slab — common after years of an undetected seal or gap failure — compromises the structural integrity of the door itself and can't be reversed. Similarly, a frame that's been fixed into masonry that's since crumbled or rotted beyond the point where new fixings will hold isn't something re-fixing can solve.
Cracked or badly warped slabs (rare, usually a manufacturing fault surfacing years later) and multi-point mechanisms that have failed alongside significant frame distortion are the other main categories where we'd recommend replacement over repair.
Repair costs in context
Composite door repairs in Cornwall typically range from £75 for straightforward hardware or lubrication work up to around £320 for more involved jobs like multi-point mechanism replacement or significant seal and frame remediation combined. Most single-issue repairs — a hinge adjustment, a lock cylinder swap, a seal replacement — sit comfortably in the lower half of that range.
We quote a fixed price after diagnosis rather than an hourly rate with an open-ended parts bill, so you know the total cost before committing to the work.
Preventing repeat call-outs
An annual service, typically around £95, is the single most effective way to catch the small issues — a slightly stiff cylinder, seals starting to compress unevenly, hinges needing a minor adjustment — before they develop into the kind of problem that needs an emergency repair. Doors serviced annually tend to need fewer reactive repairs over their lifetime and generally hold their alignment and weatherproofing for longer between visits.
What a remedial survey covers before we quote a repair
Every repair starts with establishing cause, not just symptom. We check whether a fault sits with the door leaf, the frame, the hardware, or the original installation, because treating the wrong layer wastes money without fixing the actual problem — replacing a lock cylinder won't help if the real issue is a racked frame putting the whole mechanism under tension.
This usually takes 20 to 30 minutes on site: push-testing the frame, cycling the lock and hinges, checking seal compression, and looking at the external sealant line. The survey fee is typically credited against any repair work booked as a result.
Typical repair costs across common faults
Costs vary widely by fault: hinge adjustment or replacement from around £45–£95; multi-point lock mechanism replacement £120–£220; letterbox or handle replacement £40–£110; re-sealing the perimeter £90–£160; and frame re-fixing where an installation fault has caused the symptom £120–£220. A full refit sits well above all of these at £450–£850 and should only be needed where the frame itself is compromised.
Insurance-backed guarantees and existing warranty cover
Before booking a paid repair, check whether the fault might already be covered — a genuine manufacturer's warranty on hardware typically runs 10 years, and a genuine insurance-backed guarantee on installation workmanship should still respond even if the original installer has ceased trading. We're happy to advise on whether a fault looks like a workmanship issue that should go to a guarantee first, though we can't process a claim on another company's behalf.
Second homes and coordinating repairs remotely
A large share of our repair call-outs are for owners who aren't on-site, coordinated by phone with a keyholder or letting agent opening up for us. We photograph the fault and the completed repair as standard, which matters more than usual when the owner can't see the work happen in person and needs to be confident it was done properly.
Deciding whether a repair is the right call
A repair makes sense when the fault is isolated — one hinge, one lock component, one section of failed sealant — and the frame itself tests sound. It stops making sense once you're looking at a second or third repair on the same door within 18 months, which usually signals an underlying installation or frame issue that repeated small fixes won't resolve; at that point a proper diagnostic survey is worth more than another quick fix.
Typical repair costs in Cornwall
| Work | Typical price | Notes |
|---|---|---|
| Diagnosis / assessment visit | £45–£75 | Often credited against repair cost |
| Hinge adjustment or replacement | £75–£150 | Most common repair |
| Lock cylinder replacement | £75–£130 | Security-critical |
| Multi-point mechanism replacement | £180–£320 | Where gearbox has failed |
| Seal replacement, full perimeter | £90–£180 | Weatherstrip renewal |
Guide prices only — we confirm the cost after seeing the door.
When to call a professional
- Anything you can't diagnose or fix in 30 minutes.
Prevention
- Annual service catches most problems before they become expensive.
