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Tips for Sealing Slate Floor Tiles

Slate Tile Denver

slate floor tilesSealing slate floor tiles is an essential step for several reasons. Slate is porous and may absorb liquids that cause permanent stains. Some may believe that sealing slate tiles alters the natural look. However, sealing the tile keeps the floor from accumulating the inevitable stains and blots and keeps the flooring looking new, whether a shiny or matte-finish sealant is applied.

Not All Slate is Same

Depending on their country of origin, slate materials may have a different absorption rate. The slate originally sourced in Vermont or Brazil tends to be denser and absorb less. Slate from China or India tends to be less dense and more like to absorb liquids. In any case, because the material is metamorphic and formed in sheets of clay and other materials, some porosity will always be present.

Sealing Slate: Before or After Installation?

Grout too can penetrate the surface of slate tile. Unless you are the most talented slate tile installer, the likelihood for the tile surface be in contact with the grout is significant. If each tile is coated with a sealant in advance, thereby shutting off access to the slate’s tiny openings, staining can be avoided.

Steps for Installing and Sealing Slate Tiles

  • Cleaning the Subsurface

Before starting, the surface under the tile should be thoroughly cleaned to ensure the tile is smoothly applied and grime cannot invade the slate.

  • Seal Each Slate Tile

Before installing, apply sealant to the entire surface of each tile. Make sure to follow the sealant instructions for drying times before setting the tile in place. Follow the specific instructions for the product for the sealant may be applied by spray, brush, or even roller. Allow to dry and apply a second coat.

  • Install the Tile with Grouting

Lay the tile using the appropriate grouting between the individual pieces. Mixing the grout with the sealant material rather than water can improve the bonding characteristics and strength while enhancing the moisture resistance of the grout.

  • Apply the Finish

Once the slate tiles are in place and the grout has cured completely, the surface finishes may be used. The slate surface can take on a wet, glossy look or even a matte finish depending on the choice of products. Some want the finish to retain the most natural slate look possible, highlighting the variegated coloring and patterns as much as possible.

  • Clean and Reseal

Let the surface cure for a week or more and then clean completely, removing all traces of lingering grout. When the surface is entirely dry from the cleaning, a clear sealant can be applied to protect the slate even longer.

Contact the Flooring Experts at PetraSlate


PetraSlate of Denver offers a broad range of high-quality flooring materials. For questions regarding the installation, sealing, or maintenance of slate tiles, call PetraSlate at 303.280.9595.


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