Efflorescence is a white, powdery, blotchy, or crystalline deposit on the surface of concrete, limestone, marble, or masonry products. Efflorescence in certain solid stones is a common problem.
It can sometimes occur, on rare occasions, if the panel is sitting in water or absorbed from damp soil. Generally, efflorescence is a temporary condition. If left alone, rain will naturally remove the efflorescence from stone. Once all the salts have come to the stone's surface naturally and been washed away by the rain, it should not reappear.
Efflorescence is due to moisture combining with calcium hydroxide in the limestone, marble, or cement, and then forming crystals when it reacts with the carbon dioxide in the air.
One of the advantages StonePly panels have over solid stone is the usual absence of efflorescence. This is thanks to the aluminum honeycomb backing to StonePly panels. Water is unable to permeate the stone from behind.
On rare occasions, if the panel is left sitting in water or in contact with damp soil, some minor efflorescence can be observed. Generally efflorescence is a temporary condition. If left alone, rain will naturally remove the unsightly salt deposits from the face of the stone. Over a long enough period of time, all of the salts that cause efflorescence will come to the surface and be washed away. At this point, the effects of efflorescence will not appear again.