· by Michael Blair, Nashville's Tile and Stone
Sealing is sold as a blanket service and only some materials need it. Knowing which saves both money and effort.
What needs sealing
Cement-based grout, which is porous and stains. Natural stone tile — marble, travertine, limestone, slate — which absorbs.
Epoxy grout does not need sealing, because it is not porous. Nor does porcelain or glazed ceramic tile.
What does not
Porcelain and glazed ceramic have a vitrified surface that absorbs essentially nothing. Sealing them puts a film on the surface that wears unevenly and looks worse.
A company offering to seal your porcelain floor is selling something that does nothing.
- Cement grout: seal, and reseal periodically
- Natural stone: seal, using a stone-appropriate product
- Porcelain and glazed ceramic: do not seal
- Epoxy grout: no sealing needed
- Test with water rather than following a schedule
How often
By condition rather than calendar. Drop water on the grout — if it darkens, it is absorbing and needs sealing; if it beads, it does not.
A shower floor needs it far more often than a bathroom wall, because of the volume of water it sees.
Application
The surface must be genuinely clean and dry first, or you seal the dirt in. On a floor, a penetrating sealer applied and the excess wiped promptly gives the best result.
Excess left to dry on the tile surface leaves a haze that is tedious to remove.
