Barrier EXT

From: $24.95

Barrier EXT is an easy to apply, highly durable, chemical resistant, urethane hybrid surface sealer for interior or exterior concrete and masonry surfaces. Matte finish version coming soon!



Are you shopping for a nice looking surface sealer that holds up well? This is the sealer for you! Barrier EXT is semi-gloss surface sealer that bonds really well to concrete and is super durable. It can be used for indoor and outdoor applications and doesn’t break down from full sun exposure. Plus it’s super easy to apply! It’s rolled on with a standard short nap paint roller. Two or three coats can be applied all in one day since it sets up quick and is fully cured in 48 hours… nice!

Here’s some more technical info about the sealer… Barrier EXT solves the common problems caused by applying a topical to outdoor concrete, stone, or masonry surfaces. This highly chemically resistant sealer is designed to strongly bond to varied types of surfaces and create a hard, abrasion resistant layer of protection. Though extremely strong and highly UV resistant, Barrier’s true innovation lies in its ability to repel dirt and stains while still allowing the transmission of water vapor – in other words, allowing the substrate to breathe! Now you can protect your outdoor surfaces from the harsh effects of weathering without causing spalling within the interior of the stone / concrete or delamination of the topical layer. Barrier is an excellent choice for indoor surfaces where strength and chemical resistance is required.

Modern Stone’s Barrier EXT is a highly durable, chemically resistant, film forming sealer designed for use on exterior and interior concrete, stone, or masonry surfaces. Barrier EXT’s UV resistant formula will not yellow or cloud over time and will strongly resist the harsh effects of outdoor weathering. Its water-based, satin finish requires minimal coats in order to impart extreme strength and beauty to a substrate’s surface. Barrier EXT is also an excellent choice for indoor applications that endure significant wear. Use on slate, saltillo, terra cotta, concrete/masonry, sandstone, tumbled marble, quartzite and other porous substrates where a semi-gloss finish is desired.

The videos below will help you with the application process. Each coat should be applied within one hour of each other for proper bonding. Apply multiple thin coats instead of one thick coat for best results. Keep back rolling the sealer until it’s completely clear before moving on to the next section.

COVERAGE CHART: Approximate square foot coverages for the typical job, per gallon.

  • Concrete: 300 – 400 first coat / 500 – 600 additional coats
  • Travertine: *900
  • Limestone: *900
  • Marble: *900
  • Granite: 800
  • Slate: 700
  • Quartzite: *900
  • Sandstone: 250
  • Flagstone: 250
  • Terra Cotta: 300
  • Saltillo Tile: 300
  • Brick/Masonry: 250

* Tumbled ONLY


Additional information

Weight 10 lbs
Dimensions 9 × 9 × 12 in

1 qt., 1 gal., 5 gal.