Why it rusts so quickly here
Corrosion needs three things: iron, oxygen and moisture. Salt doesn't cause rust directly — it accelerates it, in two ways.
It's hygroscopic, so it draws moisture out of the air and holds it against the metal even on a dry day. And it makes that moisture electrically conductive, which speeds up the electrochemical reaction that is rusting.
That's why a gate two hundred metres from the sea can corrode faster than one inland that gets rained on more.
It also explains where rust starts: welds, joints, bolt heads, the bottom rail where water sits, and any chip in the coating. Salt collects in exactly those places.
Why painting over rust never works
Rust is not a surface stain. It's an expanding layer that grows underneath whatever you put over it. Paint over it and:
- The corrosion keeps going, because the moisture is already there and now it's sealed in
- The rust expands, lifting the new coating from below
- Within a season you have blistering, and brown staining running down your freshly painted wall
A gate can look perfectly sound and then come away in sheets the moment a scraper touches it. That's rust that was painted over the last time.
The sequence that works
1. Get back to sound metal. Wire brushing, scraping, mechanical abrasion — whatever it takes to remove every trace of loose and flaking corrosion. This is the bulk of the work and there's no shortcut.
2. Treat what's left. Where pitting is too deep to remove entirely, a rust converter or inhibitor stabilises what remains.
3. Prime the bare metal. A zinc-rich or rust-inhibiting metal primer is the coat that actually protects. Skipping it, or using a general-purpose primer, is the most common failure.
4. Two finish coats. A direct-to-metal exterior coating rated for coastal exposure. Two proper coats, not one heavy one — film thickness built in layers performs better than the same amount applied at once.
5. Don't forget the hidden faces. The back of the gate, the underside of the bottom rail, the inside of a box section. Those are where it starts.
Galvanised metal is different
New galvanised railings and gates have a zinc coating, and ordinary paint will not adhere to zinc — it peels off in sheets within months.
Galvanised metal needs either weathering for a period, or treating with an etch primer or mordant solution to give the surface a key. If you've had a new galvanised gate fitted and paint is already peeling, this is almost certainly why.
Aluminium and PVC
Aluminium window frames and PVC can be painted, but both need specific primers and neither is a straightforward job. Worth asking about rather than assuming.
Colours that hold up
Dark greens, near-blacks, anthracite greys and traditional dark browns are the most common choices on this coast, and they hide the inevitable knocks best. Whites and pale colours look sharp but show every mark on a gate that's used daily.
We do a lot of this
Gates, grilles and balustrades are among the most common jobs that come in — a large share of it metalwork that was painted over the last time and needed doing properly the second.