Efflorescence is a temporary condition on the surface of the tile which is common in all concrete products.  The efflorescence process is caused by the chemical nature of cement.  It can appear as a chalky white bloom or in concentrated patches on the tile.  We cannot predict how long the effects will last—it will be dependent upon the type and amount of deposit on the product, local weather conditions and surroundings.  In most cases, rainwater will steadily remove the deposit, leaving the original color of the tile unharmed without further efflorescence.  The efflorescence process does not affect the quality or functionality of the roof.

For more information, view an in-depth guide on efflorescence here.