Efflorescence can appear on all paving products as white patches or a lightening of the surface colour, but seems to disappear when wet. It is formed by a normal chemical reaction which causes calcium hydroxide (lime) to migrate through the damp paving surface and then react with carbon dioxide in the atmosphere resulting in a deposit of calcium carbonate crystals. Efflorescence is very unpredictable in its occurrence and can happen at any time of the year but is more prevalent in winter.
Although there are cleaners available, efflorescence is a natural phenomenon and will generally disappear with the natural weathering process and the passage of time. Aggregate Industries cannot accept responsibility for the effect of efflorescence which can be a characteristic of all good quality products with a high cement content.