Cement grout soaks up liquid. A penetrating sealer fills the pores in the joints so coffee, wine, mop water and shower residue stay on the surface long enough to wipe away.
Sealing only works on clean grout, so it is always booked together with cleaning. Sealing over dirty grout locks the dirt in.
How sealing is done
- Deep clean and rinse of the tile and grout
- Drying time so the joints can take the sealer
- Penetrating sealer applied to the grout lines, excess wiped from the tile face
- Cure guidance before you mop or shower
Which grout needs it
Most homes have cement-based grout, sanded or unsanded, and it benefits from sealing. Epoxy grout and many newer urethane grouts are already stain resistant and do not need it. Glazed tile faces do not need sealer at all; only the joints do.
Unglazed tile and natural stone are different. Stone such as travertine or marble often benefits from an impregnating sealer across the whole surface, and the crew will tell you on the day if that is the case.
How long it lasts
In a shower or a busy kitchen, plan to reseal every one to three years. A low-traffic floor can go longer. Water that darkens the grout instead of beading on it is the sign it is time.