How to paint interior brick walls

Inspired by a helpful YouTube guide. We based this walk-through on "How To Paint Internal Brick Walls", a popular UK DIY guide that covers the full process from cleaning right through to a finished coat. The detail on how to work paint into the mortar joints is particularly useful if you have never tackled brick before.

1. Check the brick is sound and dry

Before anything else, check for damp. Press a piece of kitchen foil against the wall and tape all four edges. Leave it for 24 hours. If moisture appears on the back of the foil, the wall is damp from the outside and painting will trap it. Sort the source of the damp first.

Also check the mortar joints. Crumbly, hollow, or missing mortar needs repointing before painting. Running a key over the joints will tell you quickly which ones are sound and which are not.

2. Clean the surface thoroughly

Brick picks up a lot of dust, grease, and general grime over the years. Scrub the whole wall with a stiff-bristled brush and sugar soap solution, then rinse and allow it to dry completely. In a kitchen or near an old fireplace, use a degreaser rather than sugar soap — cooking residue and soot do not respond well to soap alone.

If there is any white powdery bloom on the surface — efflorescence — brush it off dry. Do not wet it. Then give the wall another week to make sure it has stopped forming before you prime.

3. Rake out and repoint damaged mortar joints

Use a plugging chisel or an angle grinder with a mortar raking disc to remove loose mortar to a depth of about 10–15 mm. Blow out the dust with a brush or vacuum. Mix up a sand-and-cement mortar or use a pre-mixed pointing mortar, and press it firmly into the joints with a pointing trowel.

Work it flush or with a very slight recess. A strongly recessed joint catches paint and makes the finished surface look patchy. Allow the repointing to cure fully — at least a week — before moving on.

4. Apply a stabilising primer or masonry primer

Bare brick is highly absorbent. Without a primer, your first coat of paint will soak in unevenly and you will burn through a lot of product getting coverage. A masonry primer or diluted stabilising solution gives the surface something to hold onto.

Apply with a thick-pile roller and work it well into all the mortar joints. A paintbrush on the joints first, then the roller across the face, is a reliable combination. One coat is usually enough if the brick is in good condition. Allow to dry fully before painting — check the tin for drying time, but in a ventilated room expect two to four hours.

5. Apply the first coat of paint

Use a masonry paint formulated for interior use, or a mineral-based limewash if you want a more breathable, traditional finish. Do not use standard emulsion on bare brick — it will peel. Mineral paint sits on the surface rather than forming a film, which means it can breathe.

Work with a thick-pile roller for the face of the bricks and a brush for the joints. Cut in around the edges with a brush. The first coat will look thin and streaky. That is normal. Do not be tempted to go back and keep working it — you will drag the paint and create marks.

6. Apply a second coat

Allow the first coat to dry completely — overnight is safest. The second coat goes on the same way: brush the joints, roller the face. By the end of the second coat, you should have even coverage across both brick and mortar. If there are still patchy areas, a third coat in those spots is fine.

That said, if the wall needs three full coats to get coverage, it may be worth considering whether the primer coat was sufficient. A very porous brick sometimes needs two primer coats before you start on the topcoat.

7. Finish the edges and any detail

Cut in carefully around window reveals, door frames, skirting boards, and any outlets or switches in the wall. A small cutting-in brush held at a consistent angle gives a clean line. Tape can be used, but on uneven brick it is hard to get a perfect seal and paint often bleeds underneath. A steady hand usually gives a better result.

Remove any masking tape while the paint is still slightly soft — pulling it away from dried paint risks taking chunks of the finish with it.

When to call a handyman

Call Richard if the brickwork is showing signs of ongoing damp, if large areas of mortar need repointing, or if the wall is part of a chimney breast where the flue may be open. Painting over damp brick or an active chimney creates problems that are hard to fix later. Better to get it right first time.