Quick answer
Deciding between repairing and replacing a composite door comes down to six factors: the cost of the repair itself, how much useful life the door realistically has left, its current security specification, its thermal (U-value) performance, its condition and appearance, and any warranty implications. Getting an honest quote for both options is the most reliable way to compare them properly.
Overview
Six factors decide it: cost of the repair, remaining door life, security spec, U-value, aesthetics, warranty implications.
Why this decision deserves more than a gut call
It's easy to default to 'just repair it' because that's usually the cheaper number on the day, or to over-correct towards 'just replace it' because a door with several small problems feels generally tired. Neither instinct is reliable on its own. The right approach weighs six specific factors against each other, because a door can score well on some and poorly on others — a structurally sound frame with a dated U-value, say, or a cosmetically tired slab with excellent security.
We deliberately quote both options honestly rather than steering towards whichever is more profitable for us, because most jobs genuinely are repairs, and a customer who trusts that recommendation is one who comes back for the next thing, whereas a customer sold an unnecessary replacement rarely does.
Factor one: the actual cost of repair
The starting point is always a specific, itemised repair cost rather than a vague sense that 'it needs a few things doing'. A single hinge adjustment at £75–£150 looks nothing like a combination of frame re-fixing, seal replacement and mechanism repair that might total £400–£600 across several visits. Get the real number before comparing anything else, because an unrealistically low mental estimate skews every other factor in favour of repair when it shouldn't.
Factor two: remaining useful life
A repair that costs £200 on a door with fifteen years of realistic remaining life left is a very different proposition to the same £200 repair on a door that's already twenty-five years old and showing several independent signs of ageing. The first is clearly worthwhile; the second risks being the first of several repairs in quick succession as other components reach end of life around the same time. Consider not just the immediate fault but what else on the door is roughly the same age and likely to need attention soon.
Factor three: security specification
If the fault being repaired is unrelated to security — a cosmetic scratch, a slightly stiff hinge — this factor barely moves the needle. But if the door's overall security spec is already dated (older cylinder types, externally glazed beads, a lock mechanism that doesn't meet current PAS24 expectations) alongside the fault you're repairing, that's a meaningful argument for replacement, since you'd otherwise be investing repair money into a door that still falls short on security regardless.
Factor four: thermal performance (U-value)
Doors installed before roughly 2010 commonly have noticeably worse U-values than current Part L standards expect of new installations. This factor matters most when combined with others — a dated U-value alone rarely justifies replacement, but it adds weight to the replacement side of the ledger when the door also needs a significant repair, since you'd be paying to extend the life of a door that's costing more in heat loss than a modern equivalent would.
Factor five: appearance and condition
This factor carries different weight depending on the property. A front door that matters for kerb appeal — a main residence, or a holiday let where first impressions affect bookings and reviews-adjacent guest experience — makes cosmetic condition a more legitimate part of the decision than it would be for, say, a rarely-used side door. If the finish is beyond restoration and the door faces the street or a holiday let's entrance, factor that in as a genuine (if secondary) consideration alongside the functional factors.
Factor six: warranty implications
Repairing a door that's still under a manufacturer or installation warranty may be coverable at no cost, or at reduced cost, depending on the specific fault and the warranty terms — always worth checking before paying privately for something that might be covered. Conversely, extensive private repair work on an older, out-of-warranty door doesn't come with any of the protection a new installation warranty would offer going forward, which is worth weighing if the door has multiple ageing components rather than a single isolated fault.
Getting both quotes and applying the 60% rule
Once you have a specific repair quote and a specific replacement quote, the simplest practical test is comparing the repair cost against roughly 60% of the replacement cost — starting from £1,395 fitted. Above that threshold, replacement is usually the better financial decision even before considering the other five factors; below it, repair remains sensible unless several of the other factors point strongly the other way. We'll always give you both numbers honestly so you can make that comparison yourself rather than relying on our recommendation alone.
The numbers, side by side
Typical repair costs: hinge or handle work £45–£110, lock mechanism £120–£220, re-sealing £90–£160, frame re-fixing £120–£220, full frame refit £450–£850. Replacement starts from £1,395 fitted. On pure arithmetic, anything under roughly £420 (30% of the entry replacement price) favours repair; above roughly £850 (60%), replacement usually wins on long-term value once you account for the new door's full warranty and current Part L thermal performance versus an older door's likely shortfall.
The middle band, £420–£850, is genuinely a judgement call, and that's where the door's age, exposure and fault history matter more than the raw cost comparison.
What a remedial survey adds to the decision
A proper survey before deciding tells you whether you're really choosing between repair and replace, or between a small repair and a repair you don't yet know you'll need in eighteen months. We check the frame's fixing points, drainage, and seal condition as standard alongside whatever fault brought you to us, precisely so the decision accounts for the door's overall condition rather than just the symptom you called about.
Your rights if a recent repair failed and pushed you toward replacement
If you're considering replacement partly because a previous repair — from us or another installer — didn't hold, that repair should have been carried out with reasonable care and skill under the Consumer Rights Act 2015. It's worth raising this with whoever did the original repair before committing to full replacement, since a failed repair redone properly may still be cheaper than starting over, even if trust in that outcome is understandably lower the second time.
Second homes: why replacement often wins the calculation
For an owner managing a Cornwall property remotely, every repair visit has a hidden cost in coordination and lost letting availability that doesn't appear on the invoice. Where the raw repair-versus-replace numbers sit in the middle band, this coordination cost often tips the decision toward replacement for second homes and holiday lets in a way it wouldn't for an owner-occupier who can manage a repair visit around their own schedule.
A practical way to decide, step by step
Get the current fault properly diagnosed rather than guessed at. Add up the realistic repair cost against the 30%/60% bands above. Check the door's age and whether it's had previous separate repairs. Check whether an insurance-backed guarantee or warranty might cover some or all of a repair cost. Factor in coordination cost if you're not on-site. Taken together, these five steps turn a decision that often feels like guesswork into one with a clear, defensible answer.
Typical repair costs in Cornwall
| Work | Typical price | Notes |
|---|---|---|
| Repair quote (itemised, on-site assessment) | £75–£320 | Depends on specific fault |
| Replacement quote for comparison | From £1,395 | Fitted, includes disposal and certificate |
| Combined repair + replacement assessment visit | £45–£75 | Often credited against whichever option you choose |
Guide prices only — we confirm the cost after seeing the door.
When to call a professional
- For both quotes - Cornwall Composite Doors will give you both honestly.
Prevention
- Regular maintenance keeps the balance on the repair side.
