How to Seal Grout and Tile

After installing and grouting a new tile floor, you will want to protect your work. There is an important difference between sealing tiles and sealing grout.

If you installed glazed ceramic tiles, then you only need to seal the grout. This is because the glazing protects the tiles. By sealing the grout, you help protect against mildew and staining. Sealed grout also helps protect your floor from moisture seeping under your tiles.

Sealers vary from manufacturer but a basic rule of thumb is that you should wait 1 to 2 days before applying sealer to new grout. The best way to determine when to seal is by reading the manufacturers instructions on the grout. For existing grout, it is advised to re apply sealer every two years.

Sealers come in two forms. Penetrating and Membrane forming.

Membrane sealers protect against water penetration and is best used on tile floors. They often come in the form of grout color additives with added pigments to change the original color of the grout. This can be handy if you have existing grout (such as white) and you want to change the color to something different). Another significant point to remember is that this type of sealant will not adhere to glazed tiles. In high water areas such as a backsplash or shower, water will find it's way to the tile/grout underlayment. Applying a membranous sealer makes it difficult for water to get back out and let the grout dry. This can cause rot, mold or mildew.

Penetrating sealers do exactly as it sounds, penetrates the tiny voids of the grout. Penetrating sealers are usually made of silicone or latex suspended in a water or mineral spirits base. After you apply the sealer, the base evaporates, leaving the solid material within the grout. This fills in the pores and closes the grout surface. This reduces staining on the grout.

Non-pigmented penetrating sealers can slightly darken the grout's natural color. Be sure to use a good quality penetrating sealer in bath and showers.

Silicone or water-based sealers gets applied to grout joints. If you get this type of sealer on glazed tiles, be sure to wipe it off before it dries or it will become permanent. It dries quickly and will form a haze on glazed tiles that will not come off.

If you tile is made of marble, slate and terra cotta, you will need to seal the surface of the tiles. Applying tile sealer will also help prevent moisture penetration. If you seal your tile prior to installing, it will prevent grout from getting into the tile pores. This helps prevent dulling or hazing the tile surface during grouting.

As with grout, you will want to reseal the tile every two years.