How to paint a radiator

A radiator stands out more than you might think. After years, the paint has often yellowed, there are scratches or small rust spots and the colour no longer matches the wall. A fresh coat of paint makes a big difference. Painting a radiator does take patience: the shape is awkward, the paint has to withstand heat and it is best to work in thin coats. In this blog you will read step by step how to go about it.

👷 Calling in a professional is never superfluous. If you want to take the radiator off the wall to paint it all round, or if it needs to be replaced or moved, have it done by a qualified heating engineer. Removing a radiator means the heating system has to be isolated, drained and then refilled and bled.

Which paint do you use?

A radiator gets hot. So use a paint that is suitable for radiators and heating pipes, such as a special radiator enamel. Ordinary wall paint or a lacquer that cannot withstand heat will yellow or blister. Check the label of the paint to see whether it is suitable for metal and for the temperature of your radiator, and whether a primer is needed. Bare spots and rust spots are usually treated first with a suitable metal primer.

💡 Preferably choose a colour that matches the wall. A radiator in the same colour as the wall stands out the least.

What do you need?

Preparation

• masking paper and masking film to protect the floor and the wall around the radiator.
• blue painter's tape to mask the valves, the thermostatic head and the wall next to the radiator.
• Fila Brio universal cleaner, a 12-litre bucket and a cloth to degrease the radiator.
• A wire brush to remove rust spots and loose paint.
• A sanding block grit 120 to key the old paint and a sanding block grit 220 to sand lightly between coats.

Painting

• A radiator brush with a bent handle to reach between and behind the columns.
• A narrow radiator brush for the narrowest gaps.
• A flat brush for lacquer for the edges and the pipes.
• A foam roller with a radiator roller holder for the flat parts of a panel radiator.
• A paint tray for the roller.

Personal protective equipment

• work gloves with nitrile coating when degreasing and painting.
• safety goggles when brushing and sanding, because flakes of paint and rust can fly off.
• An FFP2 dust mask when sanding, against the fine dust from old paint.

Read more about choosing the right rollers and brushes in our blog on paint rollers and brushes.

Step 1: switch off the heating and let the radiator cool down

Never paint a warm radiator. The paint then dries too quickly, gets streaks and does not adhere well. Close the thermostat and the radiator valve and wait until the radiator is completely cold. Also leave it off for at least a day after painting, or as long as the paint label states.

⚠️ If your house was built before 1994 and you have doubts about old paint layers or asbestos-containing material behind or near the radiator, do not sand or scrape. Have it tested first by a specialist company.

Step 2: protect the surroundings

Lay masking paper on the floor under and in front of the radiator and tape it down. Slide a piece of cardboard or film between the radiator and the wall so you do not touch the wall when working on the back. Mask the radiator valve, the thermostatic head and the brackets. Read how to mask neatly in our blog on masking tape and protective film.

Step 3: clean and degrease the radiator

Dust and grease often sit deep between the columns. Vacuum or brush away the coarse dust first. Then wash the radiator with lukewarm water and a degreasing cleaner. Rinse with clean water and let everything dry thoroughly.

Step 4: sanding and removing rust

Brush away rust spots and loose paint with the wire brush until you reach a firm surface. Then lightly sand the whole radiator with grit 120 so the new paint adheres well. You do not need to remove the old paint completely, just make it dull. Wipe off the sanding dust with a damp cloth. Touch up bare spots and rust spots with a suitable metal primer. Read more about filling and sanding in our blog on putty knives, sanding tools and scrapers.

Step 5: paint in thin coats

1. Start at the back and the inside. Use the radiator brush to paint the parts that are hardest to reach first: between the columns and at the back.
2. Then finish the edges and the pipes with the flat brush.
3. Paint the front last. On a panel radiator use the foam roller, on a column radiator the brush. Work from top to bottom.
4. Apply a thin coat. Thick coats run and dry poorly. Two thin coats give a much better result than one thick one.
5. Let the first coat dry thoroughly, sand lightly with grit 220 and remove all dust. Then apply the second coat.

💡 Make sure there is good ventilation while painting and drying. Open a window, but keep the room dust-free.

Step 6: finishing

Remove the tape while the last coat is not yet completely hard, for a clean edge. Let the paint cure fully before switching the heating back on. Turn the heating to a low setting the first time; new paint sometimes smells a little the first time it warms up.

Common mistakes

• Painting a warm radiator, so the paint streaks and does not adhere well.
• Not degreasing, so the paint peels off.
• Coats that are too thick and run.
• Using wall paint that cannot withstand heat.
• Switching the heating back on too soon.

Working safely

Wear gloves and safety goggles when degreasing, brushing and sanding, and an FFP2 mask against the dust from old paint. Work in a well-ventilated room and keep children and pets away while the paint is still wet. Always leave removing, moving or replacing a radiator to a qualified heating engineer.

Frequently asked questions

Do I have to take the radiator off the wall to paint it?

Usually not. With a radiator brush with a bent handle you can reach between and behind the columns. If you do want to remove the radiator, have it done by a qualified heating engineer.

How long should the heating stay off?

At least until the paint is properly dry, and preferably as long as the paint manufacturer states. Often that is a day or longer.

Can I spray a radiator?

That is possible with a suitable spray can or spray equipment, but you then need to cover the surroundings even more carefully. With a large number of radiators, a painter can do this quickly and neatly.

What do I do if there is a lot of rust or a leak?

If there is a lot of rust, or you see moisture or drips at the valve or the connections, do not paint. Have the radiator checked first by a qualified heating engineer.

Read also: How to paint a ceiling and How to paint a door

Read also: How to protect your floor during renovation

Read also: How to remove rust

Where can you find everything for this job?

At Saniso, the online store for DIYers and professionals, you will find tools, materials and personal protective equipment for your job.

• Browse our construction tools and our workwear and safety.
• Create a customer account and order easily.
• Working on a bigger project or want to hand over the job? Request a project quote.
• Book a showroom visit, at least 24 hours in advance.
• Not sure which material suits your job? Get in touch with us.

In doubt about the approach? Feel free to call in a professional.

Saniso – Build your home with Saniso.

Read also: How to paint a wall: step-by-step DIY guide