New, unsealed, slate & flagstone is subject to surface wear and staining if not properly sealed and maintained. With proper sealing and ongoing maintenance, your slate tile will be more likely to have a long lasting, beautiful and durable appearance.

The sealer selection for slate & flagstone is generally based on the desired “finished” look you want and the degree of stain-resistance you need. There are two basic types of sealers: penetrating sealers and film forming sealers. Penetrating sealers soak into the surface leaving a natural look, and they make the surface resistant to water and stains. Film forming sealers actually form a coating or film on the surface of the stone. The film creates a barrier that holds out water and stains. The film may affect the look of the stone (adding a gloss or color enhancement). To insure that the end result and appearance are satisfactory, it is recommended that the sealer be tested in a small area first. Always read product label and directions carefully before beginning to use any sealer product.

Glaze `N Seal Sealer Options for Slate


* Film-forming sealer. (Polish ***) recommended as traffic coat over sealer for interior applications only.

** Lacquer recommended for more porous stone (absorption rate above 5%).

*** May be used indoors on un-sealed, dense tile where oil resistance is not a major concern.

**** Economical water repellant. If oil resistance is needed use Stone Sealer Impregnator or Stain Defense Sealer

After the slate has been installed properly and the tiles are thoroughly clean and dry, follow the following steps. Adjust drying times and number of coats to specifics on sealer packages.

Pre-Seal if needed

  • Apply (1-2) coats of sealer as a pre-seal/grout release. All Glaze `N Seal sealers may be used as a grout release before grouting. Use same sealer for grout release as your finished sealer. Allow to dry 24 hours or more before grouting.


  • Grout according to grout manufacturer directions. Clean as you grout to minimize water contact on stone. Be sure stone is clean and dry before sealing. – Wait at least 24 hours, or more.


  • After grout clean up and drying apply sealer to stone and grout.
  • If using Film Forming type sealer; apply 2 or more thin even coats. Allow sealer to dry 1-3 hours between coats, following individual label directions.
  • If using Penetrating type sealer; apply liberal coat. Allow to dry and then apply 2nd coat if stone will accept it.
  • After final coat, allow sealer to dry overnight. Limit heavy traffic on newly sealed surface. Allow 72 hours cure time before exposed to moisture, contaminants and vehicular traffic, as sealer will continue to cure and harden for 10-14 days.
  • To test stain-resistance, sprinkle water or cooking oil drops on inconspicuous area. If this darkens the stone, additional sealer is needed.


  • FOR INDOOR USE ONLY! If film forming sealer is used, it is recommended you apply two (2) or more coats of Glaze `N Seal Floor Polish. Allow 60 minutes drying time between coats. (Use “High-Gloss ” Polish or “Matte “ Polish, depending on desired look).

Routine Cleaning

  • Maintain exterior stone by periodically hosing down or pressure washing with water and Glaze ‘N Seal’s Neutral Cleaner. Maintain your interior stone with daily sweeping or vacuuming of dirt and loose soil. Regularly damp-mop floor with water and Glaze `N Seal Neutral Cleaner. Use a minimum amount of water on floor and dry promptly.
  • Promptly wipe up any spills to minimize staining risk
  • Re-apply Glaze `N Seal Floor Polish as necessary to prevent “wear-through” of polish, thereby
    extending the life of the sealer.
  •  If polish finish is properly maintained, the stone should not require re-sealing