Has anyone come across brown stains on natural sone slabs. They are imported slabs and the stains have appeared 12 months after laying on mortar dabs (not by me). It is as if the stains are directly above the cavities between the dabs below. The stains do not react to any acid cleaner. but are unsightly and any advise on how to get rid would be greatly appreciated.
Unfotunately I cannot figure out how to post a photograph to help explain this problem.
Unfotunately I cannot figure out how to post a photograph to help explain this problem.
