How to paint a radiator

Video by Frenchic Paint featuring Craig Phillips. This walk-through is based on the video “How to prepare and paint a radiator” from Frenchic Paint, featuring Craig Phillips. It goes through the preparation steps clearly and shows how to apply the paint without ending up with streaks or brush marks. Worth watching before you start, especially the part on getting into the fins.

1. Turn off the heating and wait for the radiator to go cold

This is non-negotiable. Painting onto a warm radiator causes the paint to dry too quickly, leaving brush marks, bubbles, or a rough texture that no amount of second-coating will fix. Turn the heating off and give it a couple of hours minimum — a full day is better, particularly in winter when the system has been running hard.

It also makes sense to plan the job in warmer months if you can. In October or November, leaving a radiator cold for 24 hours while paint dries is less straightforward than doing it on a mild September weekend. That said, if it has to be done in winter, work one radiator at a time and keep the others running to take the chill off the room.

2. Choose the right paint

Standard emulsion or satinwood will not do here. You need a paint specifically rated for use on radiators — something that handles repeated heating and cooling cycles without cracking or discolouring. Hammerite Radiator Paint, Rust-Oleum, and Frenchic’s Al Fresco range (which works on radiators) are all well-regarded options available from most UK DIY shops.

The paint comes in white, off-white, and a growing range of colours. Anthracite and matt black have become popular for feature radiators, but if you just want the thing to blend in and stop looking yellow, bright white gloss or satin is still the most practical choice. Check the tin for temperature ratings — most standard radiator paints handle up to around 100°C, which is more than enough for a domestic central heating radiator.

3. Clean and sand the surface

Start with a thorough clean. Radiators collect dust, grease from hands, and airborne grime, and paint will not bond properly to any of it. Wipe the whole radiator down with a sugar soap solution and a cloth, working into the fins and around the valve connections. Rinse with clean water and leave to dry completely.

If there is flaking or chipping paint, rub those areas back with fine-grit sandpaper — 120 or 150 grit is about right. You are not trying to strip the whole radiator, just smooth out any loose edges so the new coat sits flush. On older radiators there can be quite a few layers of paint built up over the years; if it is flaking badly in several areas, a light sand all over will give the new coat something to grip. Wipe away all the dust with a tack cloth or a damp rag before you open the tin.

4. Mask off valves and the surrounding wall

Fit masking tape around the valve bodies at each end and around the pipe connections at the bottom. Paint on a valve can foul the mechanism and make it stiff to turn — or worse, mask the point where it is leaking. Run a strip of masking tape on the wall behind the radiator too, or tuck a piece of cardboard behind it if there is room. It is much easier to do this now than to cut paint off wallpaper later.

If the radiator is close to the floor, put down a dust sheet. Radiator paint drips and if it lands on a bare floorboard or a carpet it tends to stay there.

5. Apply the first coat

Use a small radiator brush — the type with a long handle and a thin head, designed for getting into the fins. A standard paintbrush will do the flat front face but will not reach the back of the fins at all. Work from top to bottom and get into the vertical channels between fins before painting the face. Any runs on the flat section can be laid off with the brush, but a drip that sets between the fins is almost impossible to fix neatly.

Apply the paint thinly. One thin coat that covers properly is far better than one heavy coat that sags and drips. Most radiator paints are quite flowing so you do not need to load the brush heavily. Go steadily and keep a wet edge. The first coat will probably look patchy in places — that is normal. Leave it to dry fully as per the tin instructions before you assess whether it needs a second coat.

6. Apply a second coat and allow to cure before turning the heating back on

Most radiators need two coats to get a clean, even finish, especially if you are painting over yellow or a darker colour. The second coat usually goes on more smoothly than the first because the surface is no longer bare metal or raw old paint. Keep the same technique — fins first, face second, work top to bottom.

Once the second coat is dry to the touch, wait at least another 24 hours before turning the heating back on. Some manufacturers recommend leaving it longer, and it is worth following that guidance. The first time the radiator heats up, the paint finishes curing, and if you do it too soon while the surface is still slightly soft, the finish can wrinkle or dull. Once fully cured, remove the masking tape slowly at a low angle so you do not lift any of the fresh paint with it.

When to call a handyman

Most people can paint a radiator themselves with a bit of patience, but call Richard if the radiator has significant rust, if you suspect the flaking paint is old lead-based paint (common in houses built before the 1970s), or if one of the valve connections has started weeping and you want it checked before you paint over it. It is also worth having a professional eye if you are painting several radiators across a renovation and want the finish to look consistent throughout. Richard covers property maintenance around Sandwich and the wider East Kent area.