Best Flagstone Sealers

admin May 28, 2014 Flagstone Sealers
Best Flagstone Sealer

Flagstone is very porous and can allow for large amounts of sub surface moisture to move up through the flagstone which is why certain sealers perform well on flagstone and other sealers will fail. The two most common types of flagstone sealers are silane-siloxane water repellent sealers and acrylic sealers.

Silane Siloxane Water Repellent Sealers for Flagstone

Silane-Siloxane water repellent sealers are the best sealer to use on flagstone. They won’t change the look or color of the flagstone and they won’t leave behind a visible surface film. Silane-Siloxane water repellent sealers work to protect the flagstone from within the pores, and reduce staining and deterioration caused by water absorption.

Silane-Siloxane water repellent sealers penetrate into the surface of the flagstone where they chemically react to form a hydrophobic barrier within the pores. Water and other liquids will bead off the surface of the flagstone and prevent staining and deterioration caused by it. Flagstone sealed with a water repellent sealer is more resistant to cracking, spalling, pitting, freeze-thaw damage, salt damage, mold and mildew, and efflorescence.

Siliconate water repellent sealers are also a popular water repellent but should not be used on flagstone. When a siliconate water repellent is applied to dark or colored surfaces they will leave behind a semi-permanent white residue. Silane-Siloxane water repellents are the best type of water repellent sealer to use on flagstone.

Acrylic Sealers for Flagstone

Acrylic sealers are used to achieve a wet look, low gloss, or high gloss finish on flagstone. Acrylic sealers are great sealers to use on concrete, but the application is a little different on flagstone simply because of the porosity. Acrylic sealers are sensitive to moisture and flagstone allows for large amounts of moisture to pass through, especially if a vapor barrier wasn’t applied before the flagstone was installed.

If you are considering an acrylic sealer on flagstone make sure you apply it to a test area to verify adhesion and life. Apply a thin light coat and then test it again with two coats. Acrylic sealers should be applied in thin coats, and are not designed as high build coatings. Acrylic sealers are great for enhancing and protecting flagstone, but again, you should always verify compatibility first. There is a higher chance of one coat surviving, but it may need to be re-coated every 1-2 years. If the acrylic sealer turns white and delaminates, you should instead consider a penetrating water repellent.

Best acrylic sealers:

 
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