All tile products, including natural stone and the grout that is used with the natural stone, can benefit from being sealed, especially in high-traffic areas and areas where things could get spilled, such as a kitchen or dining area. Imagine red juice being spilled on a light-colored grout and that juice seeping into the grout and staining. No one wants that. Sealing grout is also important in bathrooms (in showers and on tiled floors, counters and walls) where there is naturally a lot of moisture buildup.

Choosing a Sealer
Sealers can be water-based or solvent-based. Either can be used for natural stone and for the grout. A membrane-forming sealer is water-resistant. They are used as grout colorants, using added pigments to change the grout color. Membrane sealer will not adhere to glazed tiles. A penetrating sealer will soak right into all of the voids of the grout. These sealers are made of either latex solids or made of silicone. There are two different ways to seal grout correctly. Non-sanded grout is the best type of grout to use with natural stone.

Sealing the Tile
Sealing the tile itself is important with natural stone. If you were to install basic ceramic tile, you would not necessarily have to seal the tile, but when natural stone is installed, both tile and grout should be properly sealed immediately after installation. Follow package instructions for sealing the tile. Be sure to blot or wipe up spills on the tile immediately. If properly sealed, whatever is spilled should not seep into the grout lines or stain the tile, but rather it should bead up, so that it can be blotted or wiped away. Carefully clean the tile and grout without scratching the tile or disrupting the grout lines. A sponge is typically used to apply the sealer to the tile (you can purchase a tile or grout sponge from your local home improvement store).

Sealing the Grout
Sealing the grout is relatively simple. You can purchase a grout sealing bottle, which consists of a plastic bottle with a wheel at the end of it. The container is filled with the sealing solution and is dispensed in the grout lines by carefully (and slowly) rolling the wheel (which will turn as you roll) along all grout lines, being careful not to walk or kneel on areas that have been sealed. Start at the back of the room and work your way out of the room or area and allow to dry according to package directions. This same idea is used for sealing the tile (working your way out of the room). Usually, once the sealer is dry on both the grout and the tile (it can all be done at the same time), it is safe to walk on, but read package instructions and follow manufacturer recommendations for how long you should wait before walking onto the sealed area again.