Does anti-condensation or damp proof paint work?

The main types

Anti-condensation paint usually contains additives such as tiny glass or ceramic beads that add a thin insulating layer, making the surface a little warmer to the touch. That can reduce how often the surface drops below the dew point. Many also contain a fungicide.

Anti-mould paint contains a fungicide to slow mould growth on the painted surface. It is common for bathrooms and kitchens.

Damp seal or stain block paint is designed to cover water stains and seal a surface so marks do not bleed through new paint. It is meant for walls that are now dry, not walls that are still getting wet.

Masonry and exterior water-repellent treatments are applied outside to reduce rain soaking into brick or render. They are a separate category and need care so the wall can still breathe.

Why paint alone does not solve damp

Condensation happens because the air is humid and the surface is cold. A few millimetres of paint can only change the surface temperature slightly, so in a humid room water will still condense, often just a little further along the wall or on the window instead. Mould will eventually grow on top of anti-mould paint if the surface stays wet, because dust and grime build up over the fungicide.

Sealing a wall that is still damp from penetrating or rising damp can trap moisture behind the paint. It may blister, flake or push the damp further along the wall. Our guide on signs of damp walls helps you tell which type of damp you have.

When these paints are worth using

After you have brought humidity down and fixed any leaks, anti-mould paint is a good finish for bathroom and kitchen ceilings and walls, where short bursts of steam are unavoidable. Anti-condensation paint can help on a stubborn cold wall where other fixes are in place but light condensation remains. Stain block paint is useful once a wall has fully dried after a leak, so old tide marks do not show through.

Use a damp meter to check a wall is dry before painting after a leak; see damp meter readings explained.

The order that works

Fix the source first, clean off mould, let the wall dry, then paint. For condensation, that means ventilation, steady heating and a dehumidifier where needed. For penetrating damp, it means repairs outside. For structural damp, it means a proper survey.

1. 1

   Find the cause: condensation, leak or structural damp

2. 2

   Fix the source

3. 3

   Clean mould as the product label directs

4. 4

   Let the wall dry and check with a meter

5. 5

   Prime with stain block if marks remain

6. 6

   Finish with anti-mould or anti-condensation paint

See dehumidifiers for condensation →

Preparing the wall

Clean mould off before painting; painting over it does not kill it reliably. Our guide on how to remove black mould covers safe cleaning. Let the wall dry fully, sand off loose or flaking paint, and follow the paint maker's instructions on primers and coats. Ventilate well while painting and drying.

Note:Wear gloves and eye protection when cleaning mould, ventilate the room, and never mix bleach with other cleaners.

Keeping it looking fresh

Even the best paint stays clean only if the room stays dry. Use extractor fans while cooking and showering, wipe condensation off windows, keep furniture a few centimetres from outside walls, and keep humidity around 50 to 60 %. Our guides on how to stop condensation on windows and damp bathroom walls cover the habits that matter.

Frequently asked questions

Does anti-condensation paint actually work? It can reduce light surface condensation by keeping the wall surface slightly warmer, but it cannot cope with a very humid room. Fix humidity first.

Can I paint over damp walls? Not while they are still damp. Paint can blister and trap moisture. Fix the cause and let the wall dry first.

What is the best paint for a bathroom ceiling? An anti-mould bathroom paint, applied after cleaning off mould and with a working extractor fan in place.