Know what metal you're painting
Not all metalwork is the same, and the primer you need depends on it. Cast iron is the heavy, decorative metal found on Victorian railings, balconies and gates. Wrought iron is older, more fibrous and often hand-forged. Mild steel is the most common metal in modern railings and gates. Galvanised steel has a zinc coating that stops rust but needs a special primer or etch for paint to stick. Aluminium is light and doesn't rust, but needs a suitable primer too.
If you're not sure, a magnet sticks to iron and steel but not to aluminium. Galvanised steel usually has a dull, crystalline grey surface when unpainted.
Preparation: where all the effort goes
Rust spreads under paint, so all loose rust and flaking paint has to come off before repainting. On railings with years of build-up, this is the bulk of the work.
- Remove loose paint and rust with wire brushes, scrapers and abrasive pads
- Use a drill-mounted wire wheel or flap disc on larger areas – with eye and dust protection
- Treat remaining rust with a rust converter or rust-inhibiting primer
- Degrease and wash off dust before priming
- Fill pits and gaps with a metal filler if needed
- Prime bare metal the same day, before it starts to flash-rust
Choosing the primer and paint
Direct-to-metal paints combine primer and topcoat and are convenient for maintenance, but on heavily rusted or bare metal a separate primer still gives the best result. Gloss black remains the classic finish for period railings; satin is less showy and hides imperfections better.
| Metal | Primer | Topcoat |
|---|---|---|
| Cast or wrought iron | Zinc phosphate or rust-inhibiting primer | Exterior metal paint or traditional gloss |
| Mild steel | Zinc phosphate or red oxide | Exterior metal paint, gloss or satin |
| Galvanised steel | Mordant solution or galvanised metal primer | Compatible metal paint |
| Aluminium | Etch primer | Exterior metal paint |
| Sound previously painted metal | Spot-prime bare areas | Two coats of topcoat |
Primers and topcoats for common metalwork
Application tips
Railings are fiddly. Painters use small brushes, mini rollers and sometimes a paint mitt for round bars. Work from the top down so drips can be caught, and keep an eye on the underside of horizontal rails where paint is often missed. Two topcoats are usual, and the paint should be applied in dry weather with temperatures above about 8°C.
Spraying is quick for gates and panels taken off site, but outdoors overspray is hard to control. Decorators often take smaller gates to a workshop for spraying or powder-coating.
Rather leave it to a professional?
Shot blasting and powder coating
If railings are badly rusted or have decades of paint build-up, shot blasting back to bare metal and then powder coating or a multi-coat paint system can be the most durable option. Removable gates and panels can be taken to a specialist. Fixed railings can be blasted on site, but it's messy and more expensive. Powder coating can last 15–20 years.
Typical costs
| Job | Typical cost |
|---|---|
| Front garden railings (5–8m), prep and two coats | £250 – £600 |
| Single pedestrian gate | £80 – £200 |
| Pair of driveway gates | £250 – £600 |
| Victorian balcony or ornate railings | £400 – £1,200+ |
| Shot blast and powder coat a gate (off site) | £150 – £450 |
Indicative prices for repainting metalwork (2026)
Keep it looking good
Wash metalwork once a year and touch up chips straight away, before rust gets a hold. A light rub-down and a fresh topcoat every four to six years keeps railings in good order. If you're having other exterior work done, adding the railings to the same job usually costs less than booking them separately. Get prices from local exterior painters and see lead paint and Artex if your railings are old.
