What is efflorescence?
A classic example how unprotected stone and lack of regular maintenance can create a very unsightly film on Slate and other Natural Stone surfaces, particularly in wet areas.
Moisture, can and does, penetrate all Unprotected Natural Stone.
When moisture reacts with naturally occurring salts in the stone itself, the mortar setting bed, or grout, Efflorescence grows. Yes, it GROWS. Salt crystals will grow and expand and will find a way out towards the surface. Sometimes this film leaches out directly through the pores of the stone, but more often it finds its way through the path of least resistance, the joints.
Fortunately, this can be rather easily resolved and prevented by calling Grout Guys, LLC at 919-740-0984 for a professional tile/grout technician to treat it. We have free estimates and have been in the tile business for over 26 years.