Limestone tiles have a natural beauty unmatched by man-made products. However, because limestone is a sedimentary stone made primarily of calcite, it is also extremely soft and porous. Therefore, to maintain your limestone's beauty, you need to seal it with an impregnating sealer designed for soft stones. Limestone should be sealed when it is first installed, and again on a regular basis when it shows signs of absorbing water.

1
Seal newly installed limestone tiles before grouting them. Limestone tiles that have been installed for a while should be washed before sealing. Use a stone cleaner and a lint-free cloth. Spray the tiles with cleanser straight from the bottle and wipe clean. Allow the tiles to dry completely before sealing.

2
Pour some impregnating sealer into a small bowl and dip a foam paintbrush into the sealer. Apply the sealer to the limestone tile in broad strokes, covering all surfaces. The limestone should appear wet when you have applied enough.

3
Let the sealer stand for five minutes, then wipe the surface dry with a lint-free cloth. Buff the limestone in circles until completely dry and all excess sealer has been removed.

4
Wait two to three hours, then apply a second coat of sealer. Water will bead up on the surface of well-sealed limestone. When the water ceases to bead, it is time to reseal the stone. Limestone that is installed in a wet area should be sealed three or four times a year. Dry walls will need only occasional resealing, while a limestone floor should be sealed about twice a year.