Effect of weather
Cleaning should not be carried out in frosty conditions unless adequate measures are taken to protect newly applied brickwork from becoming frozen.

During hot weather it is preferable that brickwork to be cleaned should be shaded from sunlight, in order to prevent the areas being treated from drying out prematurely.

Identification of stain or deposit and masonry materials
Before commencing any cleaning operation, it is essential to identify the type of stain or deposit and the nature of the material to be cleaned. The latter is important because there are techniques that may be perfectly satisfactory for clay products but could damage other products.

The application of inappropriate cleaning agents can create further, more permanent discolouration, which can be extremely difficult to remove.

In the case of newly applied brickslips, WBS Technical Department should be consulted at an early stage, as we have detailed experience of the cleaning of our particular products, and may be able to identify the stain and to suggest cleaning techniques that have proved satisfactory in the past.

It is important to distinguish between efflorescence and a stain. Efflorescence is soluble in water, whereas the stains considered below are not. It is strongly recommended therefore, that efflorescence be allowed to weather away naturally. Improvements can be seen over a short period of time, but with some products a longer period, over several seasons may be anticipated. (See section on white efflorescence).

Cleaning small areas
Where the stained areas to be cleaned are relatively small, a suitable method is to wet down the area using a large paintbrush.

A chemical treatment may then be carefully applied to the stain using a paintbrush. Following the treatment, it may be necessary to scrub down the treated area with a bristle brush and water, with frequent cleaning of the brush in a small bucket or bowl, to ensure that the chemical is not left in the textured face of the brick. Waste water should then be disposed of giving consideration to and detrimental environmental implications.

Lime running
Such staining may occur on newly erected brickwork that has become saturated during construction. It may also occur under certain circumstances on established brickwork.

It may come from mortar joints or from concrete and cast stone units that become saturated, and derives from free lime leaching out under excessively wet conditions.

When fresh, it may be removed by scrubbing using a bristle brush and water. If left exposed to the atmosphere, lime running hardens forming a crust, known as calcium carbonate. In this condition treatment with a propietory brick cleaner is likely to be required as for cement staining.

Dirt, grime, soot and smoke
Such deposits are generally the result of long term airborne deposition and as such will be difficult to remove. Scouring powder and a stiff bristle brush may be effective if the texture is not too rough.

Care should be taken with sand textured products.

Some alkali detergents and emulsifying agents when applied by a steam cleaner have also been effective. If these cannot be removed by scrubbing with hot soapy water, it is likely that the techniques used by specialist cleaning contractors will be required.

This may involve cosmetic tinting to restore the original colouring.

Oil, grease and tar
The heavier deposits should be removed as far as possible by absorbent materials or scraping with wooden or similar implements to avoid damaging the brick face.

An aerosol freeze spray can also be used for tar prior to chipping off.

The surrounding brickwork should firstly be wetted to avoid the spread of contamination.

The deposit or stain should also be surrounded with absorbent material. This should be followed by application of a suitable emulsifying and degreasing agent in hot water.

Stubborn deposits may require scrubbing with a bristle brush.
Ensure an adequate supply of absorbent material for collection of residues.
For deeper-seated stains, seek the advice of a specialist cleaning contractor. Waste water and products should then be disposed of giving consideration to and detrimental environmental implications.

Organic growths
Such growths occur naturally and impart a mellow weathered appearance to the masonry. They generally appear on brickwork which is permanently shaded from direct sunlight and which remains cold and damp for long periods of time.

Where it is necessary for such growths to be removed, the application of a fungacide / algaecide will kill off the growths; these can then be removed by steam cleaning.

The application of biocide will help to slow down any re-growth.

Some of these products can be harmful to pets and wildlife - please read the containers carefully.

Paint and graffiti
Both are difficult to remove; hardened paint particularly so. Water-soluble paint removers to BS 3761(5) should be used in accordance with manufacturers’ instructions.
Where the painted areas are extensive, or where the paint film is particularly stubborn, it will be necessary to seek specialist advice. When using paint removers\strippers, care must be taken to prevent the rinsing waste water from entering the drains.

Paint removers\strippers are hazardous chemicals and care must be taken to ensure that all Health & Safety requirements are met.

White efflorescence
Efflorescence is a deposit of soluble minerals, which may be left on the surface of the bricks and mortar when the wall dries out.

It derives naturally from clay brick and also from cementitious products or mortar. It can also be introduced as a contaminate, for example, from ground sources and from water or airborne transmission spray.

White efflorescence can occur following wet working conditions, when the building dries out for the first time.

Under certain conditions, it may reappear, to a lesser extent over several periods of weather cycles.

It should be allowed to weather away naturally, but brushing with a non-metallic bristle brush can accelerate its removal. Care should be taken with sand textured products.

The deposit should be collected and removed so that it does not enter the brickwork at lower levels. In some situations cleaning with an industrial vacuum cleaner has been successful. Any deposit remaining may be removed by using a clean damp sponge, which should be rinsed frequently in clean water. This will assist where efflorescence is experienced internally where natural weathering conditions will not occur.

Recurrent efflorescence on older established brickwork may almost always be taken as an indication that considerable quantities of water are entering the brickwork as a result of failure of weathering and other protective measures, faulty spouts and gutters and the like.

Chemical methods should not be used for the removal of white efflorescence.

Yellow or green efflorescence
Although rare, such efflorescences can occur on new bricks, particularly on some varieties that are buff or cream in colour. They are due to the presence of vanadium salts, a transitional metal compound and a naturally occurring ingredient of some clays.

If brickwork exhibiting such efflorescences is washed with inorganic or proprietary hydrochloric acid based brick cleaning solutions, a dark coloured stain, which is permanent, is frequently produced, hence these efflorescences should be allowed to weather away naturally.

If these efflorescences are so pronounced as to necessitate chemical methods of removal, the following methods have been used, but it is strongly recommended that initial trials be carried out on small areas of brickwork.

Brush on sodium hypochlorite or household bleach in concentrated solution, and, when bleached, apply washing soda solution (12g/litre) and leave on the wall. Waste water should then be disposed of giving consideration to and detrimental environmental implications.

Remember not to clean other stains whilst vanadium salts are visible.

Under no circumstances will WBS accept liability of any sort from the use of any suggested products mentioned above. The operative must take full responsibility for existing laws and regulations and at all times operate within Health and Safety and Environmental guidance on the use of these products, which can often be found on the back of the receptacle.

The information provided within this page is deemed to be accurate to the best of our knowledge and given in good faith.