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How to Darken Flagstone

David Swan

Flagstone is derived from any evenly stratified stone -- usually sandstone -- that splits into flat pieces for paving or flooring. Flagstone generally requires a sealer to protect it from spills and surface wear.

Sandstone is an attractive paving material for patios and poolsides.

Stone enhancers are a type of penetrating sealer formulated to darken the stone and bring out its natural colors, although regular penetrating sealers also darken the stone somewhat. These products are available at stone dealers and larger home improvement stores. You may need to experiment with several brands to find the one that produces your desired level of darkening.

  1. Sweep or vacuum the flagstones thoroughly. Wash them with warm water and a sponge or mop. Let the stone air-dry completely before proceeding.

  2. Cover nearby flooring and baseboards with masking paper and painter’s tape, if necessary.

  3. Clear small children and pets from the area, and open nearby windows for ventilation. Put on safety gloves and goggles.

  4. Apply the penetrating sealer or stone enhancer with a brush, sprayer or roller -- as directed by the manufacturer. Wipe away any excess with a clean, lint-free cloth. Don’t treat a larger area than you can wipe clean before the excess sealer dries.

  5. Let the sealer dry for the amount of time specified on the product's label. Apply an additional coat, if desired.

  6. Let the treated stone cure for the amount of time specified by the manufacturer. Do not allow anyone to walk on the stone until it’s fully cured.

  7. Tip

    Test the penetrating sealer or stone enhancer on a sample piece of flagstone, if possible. If no sample pieces are available, test it first on an inconspicuous area of your installed flagstone. Allow the stone to cure for the specified time after the final coat, and then sprinkle water over the surface. On properly sealed stone, the water will bead up. If the sealer doesn’t perform as desired, test another small area using a different brand. Don’t treat your entire stone floor until you find a product that provides the color enhancement and stain protection you want.


    Keep flammable sealers and stone enhancers away from heat, open flame and sparks.

    Use sealers and stone enhancers only in a well-ventilated area. Avoid skin and eye contact.

    Some sealers and stone enhancers may not be appropriate for indoor use. Read the label carefully to ensure that the product is safe and effective for your intended use.

    Don’t use acidic or abrasive cleaners on flagstone, as these products may damage the surface.