Common Brick Companies in the UK

White Staining on Common Bricks

All brickwork, under certain conditions, can suffer forms of staining. Efflorescence is one type of white deposit found on masonry. It is formed by water, within the construction material, reacting with the natural salts contained within them and the mortar.

These salts dissolve in the water and are carried to and deposited on the surface, by the natural evaporation that occurs by air coming into contact with the surface of the wall or floor. White, fluffy efflorescent salt occurs in relatively new buildings because the brickwork was not protected during construction and has become wet. This water will find its way out, through evaporation; the salts can be brushed off and should not re-occur.

However, if a lead flashing is damaged, or joints are missing and water is allowed to continuously enter the construction material, efflorescence will continue to form. In this situation the cause must be found and eradicated. Salt neutraliser can be used as a treatment once the main cause has been eliminated. It will only be successful if:

• No more water is passing through the wall
• It can be applied directly to the brick as it will not pass through paint or other coatings
• Other causes of white patches have been investigated and ruled out

The other causes worth checking are:

• Leaks from gutters or downpipes: WC cistern overflows or water mains pipes
• Penetrating damp via a bridged cavity or poor cement pointing
• Free Lime which is the result of mortar or concrete curing and some clays used in brick making

The most effective treatment for efflorescence and free lime staining on external surfaces is time. The natural weathering of the surface, if maintained, will remove it. For a build-up of deposits on a wall, a good scrub with a dry, stiff brush (don’t use a wire brush) will remove the worst.

Follow up with a soft brush to move all the salt deposits otherwise they remain in the pores of the brickwork and dissolve again when wet. Many treatments, such as brick cleaners involve getting the surface and therefore the salts, wet again. This dissolves them and carries them into, not out of, porous surfaces.