Efflorescence appears on concrete 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 between cement and water, which causes calcium hydroxide (lime) to migrate through damp concrete to the 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 but is more prevalent in winter when concrete becomes wet and dries more slowly. Although there are cleaners available, efflorescence is a natural phenomenon and will generally disappear with the natural weathering process and the passage of time.
Lesta Paving cannot accept responsibility for the effect of efflorescence, which can be a characteristic of all good quality products with high cement content.