Sandstone & Flagstone:
Cleaning, Maintaining, Sealing

Sandstone, Flagstone maintenance and sealingSandstone is a porous, durable sedimentary rock composed of cemented sand-sized grains, predominantly quartz with silica, iron oxide or calcium carbonate. Used for countertops, flooring, showers, porches, stepping stones, pavers and vertical surfaces. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, gray and white.

Sandstone ranges from 6 to 7 on the MOH scale (a scale for determining the relative hardness of a mineral according to its resistance to scratching). The hardest mineral, at 10, is diamond. The softest mineral, at 1, is talc.

Pennsylvania Bluestone, a type of sandstone, is denser and less absorbent than Flagstone and is a gray blue with medium to high absorption

Shenandoah Valley Bluestone is limestone, not sandstone! The stone eventually fades from a deep blue to a light grey after prolonged exposure to the sun and rain. Remember, limestone is acid sensitive while sandstone is not. Bottom line: TEST first!

What are the DO's and DON'Ts of Sandstone?

  • DO clean up spills immediately to minimize damage to your stone.
  • DO use trivets or mats under hot dishes and cookware.
  • DO use place mats under china, ceramics, silver and other objects that can scratch the stone's surface.
  • DO use coasters under glasses, especially if they contain alcohol or citrus juices.
  • DO clean surfaces regularly with StoneTech™ Professional Revitalizer™ Cleaner & Protector.
  • DO use StoneTech™ Professional BulletProof™ Sealer to protect the stone.
  • DO use a tray for toiletry products in the bathroom to protect the surface from the damaging chemicals contained in many toiletry products.
  • DO use door mats inside and out along with runners and area rugs on marble floors.


  • DON'T wait to clean up spills on stone.
  • DON'T use cleaners that contain acid such as bathroom cleaners, grout cleaners or tub cleaners.
  • DON'T use vinegar, bleach, ammonia or other general-purpose cleaners.
  • DON'T use abrasive cleaners such as dry cleansers or soft cleansers.
  • DON'T use alkaline cleaners not specifically formulated for stone.
  • DON'T use scouring powders and abrasives because they will scratch the surface.
  • DON'T Place toiletry products directly on the countertop surface.

Care & Maintenance of Sandstone and Flagstone:

Sandstone requires care to ensure that sandstone lasts for years and generations and imparts natural beauty to the surroundings. Keep stone free of dust, which may otherwise produce scratches. Hence, dust interior floors frequently using a clean non-treated dry dust mop. Use warm water to clear sandstone regularly using a mop or sponge.

Natural stone is very porous. The best way to prevent stains is to treat the surface with a protective sealer. The sealer fills in the pores and repels spills on the surface, allowing you time to completely wipe it away.

We recommend that you use care and maintenance products from StoneTech™ Professional, a DuPont company, that are specially formulated to protect and enhance the beauty of your sandstone. Seal with ImpregnatorPro™ or BulletProof™ to maintain a natural color. To deepen color, seal with EnhancerPro™. Use Revitalizer™ cleaner/sealer for regular maintenance. It should never be cleaned at pressures above 800 PSI and then only if the grout is in good condition.

.Sealed and unsealed

Although we usually think of stone as "hard," it is a porous material. Natural stone has varying degrees of porosity depending on the type of stone. If left unsealed, spills and everyday messes can easily penetrate the surface. The liquid eventually evaporates but the stain is left behind.

Removal of oily stains is easily accomplished with StoneTech™ Professional Oil and Stain Remover.

Fluorochemical technology, incorporated into StoneTech™ Professional BulletProof™, EnhancerPro™ and Impregnator Pro, is the most advanced technology available, providing the ultimate shield against both water and oil-base stains. The micro-molecular formula actually bonds with the stone surface to deliver unsurpassed wear resistance and durability. And because the sealer reacts with the stone, you no longer have to worry about its porosity.

Restorative Cleaning of Sandstone & Flagstone:

Depending on the type of soil, stain or other foreign matter present, select one or more of the following options:

For stripping off any existing topical acrylic, urethane, epoxy, heavy wax coatings and epoxy grout haze:

  1. Mask off and protect any baseboards or adjacent areas to avoid splashing and overspray onto surfaces not intended to be treated.
  2. Sweep or dust mop loose dirt and debris.
  3. For heavy, hard to remove coatings, use StoneTech Professional™ Heavy Duty Coating Stripper as is.
  4. For softer coatings, dilute Heavy Duty Coating Stripper with clean water up to a 1 to 1 solution.
  5. Apply an even coat using a chemical-resistant paintbrush, roller or deck brush.
  6. Allow stripper to dwell for 20 minutes to 2 hours or as long as needed to soften coating. Heavy Duty Coating Stripper will remain active for up to 24 hours.
  7. Agitate well using a stiff nylon bristle scrub brush, stiff bristle push broom or a weighted floor machine at 130-140 lbs., 175 rpm, fitted with a scrub brush attachment.
  8. Rinse well with clean water and mop, sponge or wet vacuum to remove the remaining cleaning solution.
  9. A hard surface extraction wand and portable or truck mounted extraction machine may be used. Repeat the rinsing and wet vacuum process to insure that all dirt, soil and cleaner residue have been removed.

For cleaning of grease, oil, dirt, dry soil and soap scum from Sandstone & Flagstone:

  1. Mask off and protect any baseboards or adjacent areas to avoid splashing and overspray onto surfaces not intended to be treated. Sweep or dust mop loose dirt and debris.
  2. Strip off all topical finishes such as waxes and coatings.
  3. Prepare a solution of StoneTech Professional™ KlenzAll™ mixed with warm or hot water as suggested below:
    • Medium Duty Usage — Mix 1 part KlenzAll™ to 4 parts of water.
    • Heavy Duty Usage — Mix 1 part KlenzAll™ to 2 parts of water.
  4. Apply KlenzAll™ using a low-pressure chemical-resistant sprayer, sponge or mop.
  5. Agitate well using a stiff nylon bristle scrub brush, stiff bristle push broom or a weighted floor machine at 130 lbs.-140 lbs., 175 rpm, fitted with a scrub brush attachment.
  6. Rinse well with clean water and mop, sponge or wet vacuum to remove the remaining cleaning solution. A hard surface extraction wand and portable or truck mounted extraction machine may be used.
  7. Repeat the rinsing and wet vacuum process to insure that all dirt, soil and cleaner residue have been removed.
  8. To remove deep or stubborn oil stains not completely removed by KlenzAll™, let the surface dry and use StoneTech Professional™ Oil and Stain Remover.
    1. Apply a 1/4 inch thick coat of Oil Stain Remover to the oil stained area. Insure that Oil Stain Remover covers an area 1" to 2" beyond the stained area for the purpose of containment.
    2. Allow 2-3 days for the Oil Stain Remover to dry to a powder.
    3. Sweep and wipe up dried powder and evaluate the stained area for removal.
    4. Repeat process if needed.
    5. Remove any remaining Oil Stain Remover using mineral spirits.

For removal of efflorescence, grout haze, salts, mineral deposits and all other calcium-based stains (acidic cleaning):

  1. Test in an inconspicuous area, as some materials are acid sensitive and may etch when acidic cleaners like StoneTech Professional™ Restore™ are applied.
  2. Mask off and protect any baseboards or adjacent areas to avoid splashing and overspray onto surfaces not intended to be treated. Restore™ may damage stainless steel and other metals.
  3. Sweep or dust mop loose dirt and debris.
  4. Strip off all wax, acrylic, urethane and all topical finishes.
  5. Prepare a solution of Restore™ mixed with warm or hot water as suggested below:
    • Medium Duty Usage — Mix 1 part of Restore™ to 4 parts of water.
    • Heavy Duty Usage — Mix 1 part of Restore™ to 1 part of water.
  6. Liberally apply using a low-pressure chemical-resistant sprayer, sponge or mop.
  7. Agitate well using a stiff nylon bristle scrub brush, stiff bristle push broom or a weighted floor machine at 130 lbs.-140 lbs., 175 rpm, fitted with a scrub brush attachment.
  8. Rinse well with clean water and mop, sponge or wet vacuum to remove the remaining solution. A hard surface extraction wand and portable or truck mounted extraction machine may be used.>
  9. Repeat the rinsing and wet vacuum process to insure that all dirt, soil and cleaner residue have been removed.
  10. Thoroughly rinse all metal surfaces.

Sealing & Protecting of Sandstone & Flagstone:

Natural stone surfaces must be sealed to prevent or minimize staining. Leaving natural stone untreated may greatly hinder the complete removal of stains in the future. The following suggestions are for impregnating the stone and will allow the stone to breathe. Allow new installations to cure for 72 hours prior to applying sealer.

For a natural looking protector on interior surfaces (heavy duty protection, water and oil repellency):

  1. Sweep or vacuum all dust, dirt and debris.
  2. Mask off and protect any baseboards or adjacent areas to avoid splashing and overspray onto surfaces not intended to be treated.
  3. Insure that surface is clean and residue-free.
  4. StoneTech Professional™ Stone Sealer may be applied to damp surfaces one hour after standing water has been removed.
  5. Liberally apply an even coat of sealer using a low-pressure chemical-resistant sprayer, roller or brush.
  6. Allow sealer to penetrate the surface for 20-30 minutes. During this time, distribute excess over entire area to insure even penetration.
  7. Wipe off any remaining sealer prior to drying on the surface.
  8. A second coat may be needed for porous, absorbent surfaces and should be applied 30-40 minutes after initial application as directed above.
  9. A minimum of 30 minutes after final application, wipe entire surface with a towel dampened with sealer to remove any residue and excess sealer, if needed.
  10. A full cure is achieved after 24-72 hours; foot traffic may begin in 6-8 hours. Cover with red rosin paper, if foot traffic must resume before the recommended time periods have passed.
  11. Expected coverage is 300-500 sq. ft. per gallon.
  12. Re-application of Heavy Duty Stone Sealer:
    • 3-5 year re-application is needed for interior surfaces.

For a natural looking protector on EXTERIOR surfaces (heavy duty protection, water repellency only):

StoneTech Professional™ Heavy Duty Exterior Stone and Masonry Sealer is a water repellent specially designed for exterior projects such as facades, cladding, pool decks, parking areas and driveways. It is very resistant to chemicals (i.e., chlorine) and to the effects of weather (i.e., ultraviolet light/sunlight, driving water/rain).

  1. Sweep or vacuum all dust, dirt and debris.
  2. Mask off and protect any baseboards or adjacent areas to avoid splashing and overspray onto surfaces not intended to be treated.
  3. Insure that the surface is clean, dry and residue-free.
  4. Liberally apply an even coat of Heavy Duty Exterior Stone and Masonry Sealer with a brush, paint roller or solvent-resistant low-pressure sprayer.
  5. Allow sealer to penetrate the surface for 15-30 minutes; denser material may require more time for sealer to penetrate.
  6. During this time, distribute excess over entire area to insure even penetration.
  7. Wipe off any remaining sealer prior to drying on the surface.
  8. A second coat may be needed for porous, absorbent surfaces and should be applied one hour after initial application as directed above.
  9. If sealer was not completely wiped off and a residue appears, wipe entire surface with a towel dampened with sealer.
  10. Use a white, non-abrasive nylon brush or pad to loosen residue and follow with a clean, white absorbent towel to remove.
  11. Do not walk on surface for at least 4-6 hours. Full cure is achieved in 24-72 hours.
  12. Expected coverage is 300-500 sq. ft. per gallon.
  13. Re-application of Heavy Duty Exterior Stone and Masonry Sealer:
    • A 5-10 year re-application is recommended for exterior surfaces.

For a color enhancing, impregnating (non-topical) protector on interior and exterior surfaces (heavy duty protection, water and oil repellency):

  1. Sweep or vacuum all dust, dirt and debris.
  2. Mask off and protect any baseboards or adjacent areas to avoid splashing and overspray onto surfaces not intended to be treated.
  3. Insure that surface is clean, dry and residue-free.
  4. Liberally apply an even coat of StoneTech Professional™ Enhancer Pro™ using a low-pressure solvent-resistant sprayer, roller or brush.
  5. Allow to penetrate the surface for 15-30 minutes; denser material may require more time for Enhancer Pro™ to penetrate.
  6. During this time, distribute excess over entire area to insure even penetration.
  7. Completely wipe surface dry.
  8. DO NOT ALLOW ENHANCER PRO™ TO DRY COMPLETELY ON SURFACE!
  9. Failure to remove enhancer from the surface may result in a film or residue that may need to be mechanically removed.
  10. A second coat may be needed for porous, absorbent surfaces or if a darker appearance is required and should be applied one hour after initial application as directed above.
  11. A full cure is achieved after 24-72 hours; foot traffic may begin in 6-8 hours.
  12. Cover with red rosin paper, if foot traffic must resume before the recommended time periods have passed.
  13. Expected coverage is 300-500 sq. ft. per gallon.
  14. Re-application of Enhancer Pro™:
    • A 3-5 year re-application is needed for interior or exterior surfaces.

Maintenance Cleaning

Highly alkaline, acidic, ammoniated, abrasive cleaners and/or bleach may break down the sealer, adversely affecting repellency and may not be good for the stone. Use a neutral cleaner specially formulated for natural stone.

For routine cleaning with protection (not recommended for lacquered surfaces):

  1. Sweep or dust mop loose dirt and debris.
  2. Prepare a solution of StoneTech Professional™ Revitalizer™ concentrate mixed with warm or hot water as suggested below:
    • Light Duty Usage — 1 part Revitalizer™ to 4 parts water.
    • Medium Duty Usage/Spray Refill — 1 part Revitalizer™ to 1 part water.
  3. (One gallon of concentrate makes up to five gallons of ready-to-use solution.)
  4. Apply the Revitalizer™ solution using a low-pressure chemical-resistant sprayer, mop, sponge or automatic scrubbing machine.
  5. No rinsing needed.
  6. Or use Revitalizer™ in a ready-to-use sprayer.

For routine maintenance cleaning:

  1. Sweep or dust mop loose dirt and debris.
  2. Prepare a solution of StoneTech Professional™ All Purpose Stone & Tile Cleanerr concentrate mixed with warm or hot water as suggested below:
    • 2 ounces All Purpose Stone and Tile Cleaner in 1 gallon of water. (Do not mix stronger than 2 ounces to a gallon as a maintenance cleaner. One gallon of concentrate makes 65 gallons of cleaning solution.)
  3. Apply the solution using a sponge, mop or automatic scrubbing machine, then wipe or rinse off.
  4. Or use All Purpose Stone and Tile Cleaner in a ready-to-use sprayer.

Products to Clean, Maintain, Protect and Seal Sandstone & Flagstone:

Additional Stone Care Information:

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