Quick answer
A simple maintenance schedule — monthly wipe-downs and screw checks, quarterly silicone treatment of hinges and seals, twice-yearly cylinder lubrication and drainage clearance, and an annual full service — keeps a composite door in good condition for 20 years or more. None of the routine steps require specialist tools, though the annual service is best done professionally.
Overview
A simple maintenance schedule keeps a composite door in top condition for 20+ years.
Why a schedule beats reactive maintenance
Most door problems that end up as call-outs didn't appear overnight — they built up gradually from small, easily preventable beginnings that simply weren't caught because nobody was looking. A structured schedule turns maintenance from a reactive scramble into a predictable, low-effort routine, and it's genuinely more effective at extending a door's life than an occasional deep clean whenever something starts to feel off.
This matters more in Cornwall than in most of the country because coastal exposure — salt air, UV, driving rain — accelerates every one of the wear processes a schedule is designed to catch early. A door maintained on this kind of schedule can comfortably reach the upper end of its 20–35 year expected lifespan; one left entirely alone often needs significant remedial work well before that.
Monthly: the two-minute check
Monthly maintenance is deliberately minimal — a quick wipe of the slab with a damp cloth to remove salt residue and general grime before it has a chance to sit and dull the finish, and a glance at the handle and letterbox screws to make sure nothing's worked loose. This takes under two minutes and catches the earliest, cheapest-to-fix signs of hardware wear.
It's also a good moment to just operate the door and notice anything that feels different from last month — slightly more resistance locking, a faint new noise from a hinge. None of these need action yet at this stage, but noting them helps flag whether the quarterly or annual check needs particular attention to a specific area.
Quarterly: hinges and seals
Every three months, a light application of silicone spray (not household oil, which attracts dirt) to the hinges keeps them moving freely and helps prevent the early corrosion that coastal air accelerates. At the same time, run a hand around the compression seal with the door shut, feeling for any section that isn't making even contact — catching an early gap here, before it's visible as a draught or a leak, is one of the most cost-effective habits in this whole schedule.
This is also a sensible point to check the external silicone joint around the frame for any early cracking, particularly on elevations that catch the worst of prevailing weather.
- Silicone spray on hinges (not household oil)
- Hand-check compression seal for even contact
- Visual check of external silicone joint for cracking
Twice yearly: cylinder and drainage
Twice a year, lubricate the lock cylinder with a proper graphite or PTFE-based lock lubricant, worked in by turning the key or fob a few times to distribute it through the mechanism. At the same visit, check that the drainage slots along the base of the outer frame are clear — these are easy to overlook because they're low down and unobtrusive, but blocked slots mean water that should drain away instead pools against the frame.
This is a good moment for a broader visual sweep too: check the threshold for wear, look for any new gaps around the frame perimeter, and confirm the door still closes with the same light pressure it always has.
Annually: the full service
The annual full service is the point where a professional visit adds real value beyond what the lighter DIY checks can achieve — gearbox greasing, proper hinge adjustment if any drift has crept in, a thorough compression check across the whole perimeter, and slab conditioning to protect the finish long-term. This is also when small issues flagged during the year's lighter checks get properly assessed and, if needed, resolved before they develop further.
You can do a reduced version of this yourself if you're confident and have the right products, but the gearbox and multi-point mechanism in particular benefit from professional attention since incorrect lubrication or adjustment here can cause more harm than good.
Adapting the schedule for exposed or high-use doors
A door on a particularly exposed coastal elevation, or one used constantly (a busy holiday let's main entrance, for example), benefits from tightening this schedule slightly — moving to a twice-quarterly hinge and seal check, or bringing the annual service forward to every nine or ten months rather than the full year. It's a minor adjustment that meaningfully extends the life of hardware working harder than average.
What this schedule won't catch
Following this routine diligently significantly reduces the likelihood of most common problems, but it won't catch everything — issues stemming from the original installation (frame movement, an undersized keep fixing) sit outside what a maintenance schedule is designed to address, since they're structural rather than wear-related. If something feels persistently wrong despite good maintenance, it's worth having it properly assessed rather than assuming the schedule alone should have prevented it.
A practical schedule matched to Cornwall's exposure bands
Exposed coastal elevations: visual check every 6 months, full service annually. Sheltered coastal or exposed inland: visual check annually, full service every 18 months. Sheltered inland: visual check annually, full service every 24 months. A visual check is a five-minute look at the seal, silicone line and lock action; a full service is the proper 30–45 minute job covering lubrication, adjustment and drainage.
These bands assume a standard modern composite door correctly installed in the first place — a door with a known installation fault needs its own more frequent monitoring regardless of exposure, since the underlying issue won't resolve itself on a maintenance schedule.
What happens when a schedule is neglected
Neglect doesn't show up as a single dramatic failure most of the time — it shows up as a slow accumulation of small faults that eventually combine into an expensive one. A perished seal that's never replaced lets moisture reach the frame; a lock that's never lubricated wears its mechanism under extra friction; drainage slots left blocked let water pool against the cill. Individually, each is a £40–£100 fix caught early. Left three or four years, they compound into the kind of job that starts at £450 for a refit.
Second homes: a maintenance schedule someone else can follow
If you're not on-site to run your own schedule, write a simple one-page checklist for whoever does check the property — cleaner, agent, neighbour — covering the handful of things that matter: does the door lock without extra force, is the silicone line intact, is there any visible gap at the frame. None of it requires trade knowledge, and catching a problem at this level costs nothing beyond a phone call to book someone in.
Cost of a maintained door versus an unmaintained one over time
Over a ten-year ownership period, a door on a maintenance schedule typically costs £450–£850 in cumulative servicing on an exposed coastal property, spread across annual visits. An equivalent unmaintained door commonly needs at least one reactive repair in that period costing £120–£220, and has a meaningfully higher chance of needing a full refit at £450–£850 if a fault like frame movement or seal failure is left to progress unchecked.
Building a schedule around Part L and Part Q compliance checks
It's worth using a scheduled service visit to also confirm your compliance paperwork is still on file — the original CERTASS certificate confirming Part L thermal and Part Q security compliance. This matters most if you're approaching a sale, since buyers' solicitors routinely ask for it, and it's far easier to locate a certificate during a calm annual check than to chase it up under time pressure during a house sale.
Typical repair costs in Cornwall
| Work | Typical price | Notes |
|---|---|---|
| DIY maintenance products (lubricant, silicone spray) | £15–£30 | Lasts most of a year |
| Annual professional service | £85–£120 | Recommended alongside DIY routine |
| Adjusted schedule for high-exposure doors | £95–£150/yr | More frequent professional attention |
Guide prices only — we confirm the cost after seeing the door.
When to call a professional
- Annual service.
Prevention
- Following this schedule is the prevention.
