close up of a gloved hand cleaning a brick wall with a brush

Handy guide: How to clean brickwork

There is no single best way to clean brickwork. The techniques and methods of brickwork cleaning must be determined on a case-by-case basis, depending on the reason cleaning is required. You’ll also need to consider where the brickwork is. Do you need to clean exterior brick walls, interior brickwork, brick pavements, or another type? Some techniques, such as pressure washing might be suitable for outdoor brick cleaning but isn’t suitable for indoors.

Cleaning brickwork:

Here are a few common brick cleaning techniques that may be suitable for cleaning clay brickwork. With every method, we highly recommend testing on a small, hidden area for committing to the whole area.

Cleaning bricks with water & detergent – for stains, soot, and grime
Cleaning bricks with chemicals – for moss and algae
Cleaning bricks with paint remover – for dried paints
Cleaning bricks with brushes – for efflorescence

How to clean a brick wall: removing stains from

A simple hot water and detergent mix is the most common type of brick cleaning technique, and can be used for various cleaning needs. Before starting, ensure stains are just stains and not a sign of something more as this may need special attention and treatment.

To remove stains, mix according to detergent instruction and apply to walls using a stiff brush. This method should remove most surface stains. You might look a bit odd taking a broom to a wall but it’ll do the job! If the stains remain, you may wish to apply an acid-based solution and scrub with a stiff brush.

Avoid doing this type of cleaning in direct sunlight and this might dry the bricks too quickly.

How to clean an exterior brick wall: removing moss and algae

If you notice green/yellow stains on brickwork that looks fluffy, it's probably moss or algae. Sometimes these growths are seasonal and will disappear at points in the year. But if required, algae and moss can be removed with relative ease.

Use a trowel or a brush to remove any loose bits of growth. Then apply a brick cleaner with algaecide properties which will kill the growths. You can then use a pressure washer to remove anything less. Use pressure washers on brickwork at an angle and at a distance rather than parallel and up close to prevent damage. Always use a pressure washer on the lowest setting with bricks, however tempting it may be to use a more powerful jet.

Removing organic matter, such as ivy, is more difficult. Sometimes ivy becomes embedded in brick textures which causes damage upon removal. In cases like this, seek advice on the best way to remove it.

How to clean a brick wall: getting paint off

One of the biggest challenges with brick cleaning is removing paint from brickwork, including graffiti and other paints. The type of paint used and the brick surface will also affect the difficulty of cleaning. There are some interesting removal ideas out there, such as using WD-40, but we would always recommend getting advice based on these two factors before attempting removal, but scraping and using paint remover could work for certain dried paints.

Scrape as much dried paint off the brickwork as you can without damaging the surface. Apply a specialist masonry paint remover as per the instructions. You may need to repeat this process multiple times depending on the layers of paint. It’s likely you will need to tint the bricks following paint removal.

How to clean an exterior brick wall: treating efflorescence

Efflorescence on bricks is the presence of salt deposits which form after evaporation of water in bricks. This will often look like white marks on bricks, although it sometimes appears brown, green, or yellowish. The good news is efflorescence in bricks isn’t likely to cause damage to brickwork. It’s common to see efflorescence on bricks after a wet season, and will probably go away when warm weather comes around. However, if the appearance is bothersome then there are simple ways to remove efflorescence from bricks, using just a stiff brush.

Use a stiff bristle or nylon brush to dry brush the salt deposits away. Never use a wire brush. If there are any stubborn parts, you can use a damp sponge as the salt is water-soluble, but don’t saturate the area as this might push salt back into the brickwork.

Guidance when cleaning brick walls and what to avoid

Consider the time of year, will your problem likely go away with changing season? Think about this before taking drastic steps to remove blemishes from bricks.
Don't unnecessarily clean old brickwork. It is more vulnerable and cleaning may cause more harm than you started with.
Never use a pressure washer on old brickwork. Older buildings may not have been built with the same damp prevention methods that modern masonry uses.
Reconsider using water-resistant solutions and paints on bricks. In some cases, this might be suitable but be wary as these can sometimes trap moisture within the bricks.
Avoid the temptation to use metal brushes on bricks as this will likely damage the appearance.

There isn’t a definitive guide to one method of brick wall cleaning, as it really does depend on a number of factors. Always check with the brick manufacturer if you have any doubts about cleaning techniques. Plus, our colleagues in branch will be happy to offer suggestions. drop into your local Gibbs & Dandy with details about your issue and we’ll always do our best to help.

We'd recommend these further reading resources on cleaning bricks: