I am laying down an unsealed limestone tile (smoothe surface)in our front hall. I am told that the limestone is very porous and I need to seal the tile before grouting - or the grout will stain the tile. I have a ********** sealant called "SurfaceGard Penetrating Sealer" with Teflon. Will this suffice, or do I need to purchase something else.

Another question - we wanted to add Stainless steel accent tiles, but are able to only find those 1/4" thick - vs. the 3/8" of the floor tile. Can you just put an extra heavy layer of mastic underneath it to even out the floor heights - or am I just asking for trouble.

Any help would be appreciated