Brickwork offers an attractive aesthetic for the exterior of a building, while also being durable against the effects of the weather. However, brick cleaning is necessary at some point for buildings using the material, whether it is shortly after construction or many years later.

Soiling can occur during construction, often from mortar residue, while other substances can also lead to staining across the brickwork. Different stains require different brick cleaning methods, and there are some methods that should be avoided entirely.

Never Clean Bricks with a High Pressure Washer

Before discussing what cleaning methods you can use for brickwork, it is important to understand the one method that you should never use – high pressure cleaning. Pressure washers are widely used for all kinds of masonry cleaning, yet it is unsuitable for brickwork.

This is because the pressure from the water removes the mortar while damaging the surface area of the bricks. Not only does this look unsightly, but it also leaves the bricks more susceptible to damage from the weather, with rain and frost more likely to penetrate the bricks.

So, if there is one thing to avoid when cleaning bricks, it’s the use of high pressure washers!

Cleaning Mortar Stains

Mortar stains often develop during the construction of brick walls. This is caused by excess mortar drying on the surface, leaving unattractive stains across the brickwork. Removing mortar stains is one of the most common types of brick cleaning, being relatively straight-forward to complete.

Before any cleaning takes place, it is important to hose down the wall with water to saturate the bricks. Do not use a high pressure washer for this, just an ordinary hose will suffice.

Once saturated, use metal scraper to remove the mortar stains protruding from the brickwork. After this, the wall is cleaned using a brick cleaning hydrochloric acid, which is available from hardware stores.

The acid is diluted with water, which is then applied to the brickwork using a spirit brush. Cover roughly 1m of brickwork with the cleaning agent before stopping to hose it off with water, repeating across the entire brickwork.

Remember – don’t let the acid dry into the bricks!

Certain brickwork, such as red bricks with white joints, may require additional scrubbing when hosing off the acid solution. A hard bristled brush should suffice for this.

Cleaning Efflorescence Stains

Efflorescence stains are recognisable for the white residue it leaves across the bricks.

This often appears after other types of cleaning, with the white powdery substance accumulating on bricks when too much acid is used to clean them. It can also occur from exposure to salt in nearby substances, such as limestone, sea spray or even garden fertilisers.

Newly laid bricks often have these stains, and while the rain will naturally wash it away over time, the process can take too long for some.

To quickly remove these types of stains using a damp sponge. Avoid using too much moisture in the sponge, as this may cause salts to seep back into the porous surface of the bricks. Another method is to scrub the salt stains using a hard bristle brush, then rinse with clean water.

Cleaning Paint Stains

When bricks are vandalised with graffiti, it leaves an unsightly appearance that may reflect poorly on the building owner, especially if it is a business premises. Painted brickwork is also common on properties, although some may want to remove this to reveal the natural appearance of the bricks.

In in any case, to clean paint from brickwork, a standard paint remover should be applied to the bricks.  Make sure to saturate the wall with water before applying the paint stripper, gently scrubbing the paint off once the remover sets in.