1.     Pre-sealing should only be done if the tiles are of such a nature that grout staining is probable. Examples are unfilled travertine.

2.     Pre-sealing should be done when the tiles are acid sensitive and grout removal with an acid based cleaner is not possible. Examples are polished limestone, marble and travertine as well as cement tiles and polished terrazzo.

3.     Pre-sealing should be done in the case of wall tiling where cleaning with an acid based cleaner may not be possible. Examples are where carpets, wood or marble floors are already installed.   

4.     Pre-sealing should be done for wall cladding where access may be difficult and costly later and where the stone will most likely not require cleaning after installation.