White Efflorescence, a naturally occurring phenomenon on brick, concrete or stone walls and floors, is a loose, powder surface deposit. It usually disappears when the surface is wet and then reappears as the surface dries. It is caused by water-soluble salts, carried in either rainwater, construction water, or groundwater; as the water evaporates it leaves the crystallised salts on the surface.
Pressure washing can work to remove white efflorescence once the surface has thoroughly dried. The surface must be thoroughly rinsed to ensure that no residue remains. We also use a safe detergent to ensure a thorough clean.
Efflorescence is a naturally occurring phenomenon and is hard to prevent. Measures to avoid efflorescence can include using concrete of maximum density and low water absorption and ensuring that building materials are stored in a dry place, off the ground.
We have worked on a number of building cleans, where we clean up brick work and other external surfaces after building work has been completed. One of these involved removing unsightly white efflorescence from a red brick façade on a building in Braggs Lane.
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