Can I Seal Natural Slate Tile Without It Darkening?

Purpose

• Sealers either penetrate the tile or sit on the surface and create a protective barrier on top of it. They come in many varieties, some to provide a completely natural finish, some to enhance the color and add shine. Some sealers darken the tile, while others bring out the existing color of the material. Sealers also block efflorescence, the appearance of a chalky substance on the tile caused by salts left behind as moisture evaporates from within the stone.

Penetrating

• Penetrating, or impregnating, sealer soaks into the stone, filling the pores to capacity. Once the pores are filled, the tile cannot absorb anything more. This protects it from absorbing stains. Penetrating sealer does not darken the tile and should be chosen if you want to keep a natural color. Enhancing sealers impregnate the stone even more deeply and can cause darkening and a glossy finish to the surface.

Topical

• Topical sealers sit on top of the tile and often are mixed with oil. The oil causes a darkening of the surface color. These sealers could be likened to the protective clear coat placed over the paint on a car and the clear varnish brushed over stained wood. Use topical sealers if you wish to cover up all of the chalk-like textures of natural tile and achieve a very high-gloss surface and rich luster.

Bases

• Sealers come as either water-based or solvent-based. Enhancing sealers are solvent-based, which allows them to soak in deeply. Water-based sealer has less odor during application but can sometimes result in hazing of the tile after time has passed. Water-based sealer also is less forgiving, making it more difficult to work with. While solvent-based sealer gives off fumes, the fumes last only while the sealer is wet. Once it dries, there is no longer any odor.