Clean exterior brickwork

Clean dirt, algae and moss off exterior brickwork safely, using the right brush and cleaner without damaging bricks or mortar.

CEB-01Inspect the wall before you startWalk the length of the wall and look closely at the brickwork and mortar joints. Note any crumbling mortar, cracked or spalling bricks, loose render, or damp patches — clean around these rather than scrubbing them, as cleaning can make loose areas worse. Check whether the dirt is general grime, green algae or moss, or white powdery efflorescence, as this decides which cleaner you need.

RULES

KNOW THE RULES

If your home is listed or in a conservation area, check with your local council before chemical cleaning brickwork. This can count as work affecting the building's appearance and may need Listed Building Consent.

CEB-02Protect plants, glass and woodworkMove pots and cut back plants growing close to the wall, and lay a dust sheet or old towel over flower beds directly below. Mask off any nearby painted timber, outdoor lights or sockets with tape and plastic sheeting so cleaner and runoff don't damage them.

1 each · Dust sheet or old bedsheet

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1 roll · Masking tape

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2 m · Plastic sheeting

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CEB-03Gather tools, PPE and check the weatherGet a stiff synthetic-bristle brush (never a wire brush — it scratches brick and leaves rust marks), a bucket, a hose or watering can, and gloves and safety glasses. Pick a dry, mild day with no rain forecast for 24 hours and no frost, as most cleaners need time to work and can be washed away or frozen before they finish.

1 each · Stiff synthetic-bristle brush

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1 each · Bucket

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1 pair · Waterproof gloves

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1 each · Safety glasses

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CEB-04Set a ladder up safely if you need oneFor anything above head height, use a stepladder or leaning ladder on firm, level ground, angled at roughly 75 degrees if leaning. Never overreach — move the ladder instead — and get someone else in the house to know you're up there. Don't carry a bucket of chemical up a ladder one-handed; use a smaller container or a spray bottle instead.

CEB-05Choose the right cleaner for the dirtFor general grime, warm water with a splash of washing-up liquid is enough. For green algae, moss or black staining, use a proprietary fungicidal brick and patio cleaner, diluted as the label says. For white powdery efflorescence, dry-brush it off with a stiff brush first — don't wet it, as this can drive the salts back into the brick.

5 litre · Fungicidal brick and patio cleaner

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CEB-06Test on a small hidden patch firstApply your chosen cleaner to a small, unobtrusive area — low down or round the back of the house. Leave it for the time stated on the label, then rinse and check the brick colour and mortar haven't changed before treating the whole wall.

CEB-07Apply the cleaner and scrub gentlyWork in manageable sections from the top of the wall down, so dirty runoff doesn't drip over patches you've already cleaned. Apply the cleaner, let it dwell for the time stated on the label, then scrub with the stiff synthetic brush along the brick faces and mortar joints. Never use a wire brush, wire wool or a metal scraper — they scratch soft brick and leave rust stains.

CEB-08Rinse thoroughly with clean waterRinse each section with clean water from a hose on a gentle spray or a bucket and brush, working top to bottom again. If you're using a pressure washer, keep it on the lowest setting with the nozzle at least 300mm from the wall, and don't use one at all on old, soft brick or crumbly lime mortar — it can blast the pointing straight out.

CEB-09Treat any stubborn marks and let the wall dryRepeat the cleaning step on any patches that are still marked, rather than scrubbing harder in one spot. Keep chemical runoff away from ponds, drains and plant beds, and don't mix different cleaning products together. Let the wall dry fully — this can take a full day — before deciding if it needs a second treatment.

CEB-10Clean up and put everything awayRinse your brush and bucket, and dispose of any leftover chemical exactly as the label says — don't pour it down an outside drain. Take off your PPE, remove the dust sheets and masking once the wall is fully dry, and put plants and pots back in place.

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