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← All guides · Published July 2026 · Richard Lim

Salt-corroded hinges are Dover’s quiet running cost.

If you live within a kilometre of the Channel, or up on the cliff-top belt from St Margaret’s round to Kingsdown, your external hinges are on a five-year clock. Most people don’t notice until the gate falls off. The fix is one part-swap and one specification choice.

What’s actually happening

Salt-laden air lands on any external metal fitting and provides a persistent electrolyte for corrosion. Galvanised hinges - the standard trade default - are zinc-coated mild steel. The zinc layer is thin (typically 20-40 microns on trade-grade fixings). In Dover, salt exposure eats that zinc in three to four years on cliff elevations, four to six years lower down. Once the zinc is gone, the mild steel underneath starts rusting immediately and structurally, and the pin gives up.

‘Stainless’ hinges are sold in two grades that the trade often blurs. A2 (grade 304) stainless is the cheap option and is fine inland. On a Dover cliff-top belt or seafront property, it rusts through the surface finish in three to four years - slower than galvanised, but not by much. A4 (grade 316) stainless contains molybdenum, which is the difference. A4 is the marine-industry standard for anything on a boat, a dock, or a cliff-elevation property. It doesn’t rust in Dover salt.

How to spot early failure

• Green-yellow powder around the hinge knuckle. That’s zinc oxide - the galvanised layer failing. You’ve got six to twelve months before mild-steel rust starts under it.
• Brown streaks running down the paint below the hinge. That’s the mild steel already rusting; the fitting is on borrowed time.
• Play in the pin when you close the gate. Structural degradation - the pin has thinned. A gust in a January easterly will finish it.
• Rust bleed into the timber of the gate or door. The fixing screws are also failing; the timber will need a light sand and prime after replacement.

The replacement standard

For any external hinge in a Dover coastal or cliff-elevation property, spec A4 (grade 316) marine-grade stainless. Cost is around a couple of pounds more per hinge over A2, and around four to six pounds more over galvanised. On a standard 100mm gate hinge, that’s the difference between a five-year fitting and a fifteen-plus-year fitting. It pays for itself the first time you avoid replacing it.

Same applies to the screws. A stainless hinge with mild-steel screws is a false economy; the screws rust and pull, and you’re back to square one. A4 stainless screws, sized to the hinge.

Where the wider trade gets it wrong

Most builders’ merchants in Kent stock A2 stainless and call it ‘marine grade’. It isn’t - the marine industry means A4. If a trade quote for external fittings doesn’t specify A2 vs A4, ask. If they can’t answer, the safe assumption is A2. On a normal Dover property that’s a five-year fitting instead of a fifteen-year one, and you’re paying for the difference in labour twice.

The other common miss is the fixing pattern into the timber. Salt-humid Dover timber (particularly gate posts and door frames) softens around the fixing hole faster than inland timber. A hinge that’s been on for eight years has often loosened not because the hinge failed, but because the timber around the fixing has - and re-driving the same screws into the same hole gives another eighteen months at best. The right move is to plug the failed fixing hole with an epoxy dowel and re-drill fresh, or step up one screw gauge.

Practical scope

Full external-hinge audit and replacement across a Dover property is a half-day job on a standard house (front door, back door, side gate, garden gate). If we’re on the property for other work anyway, we’ll walk the external ironmongery in ten minutes and quote the fittings that are within a year of failure. Almost always cheaper to catch them then than after the gate’s come off the post.