In construction, anything rolled or sprayed promises to reduce labor—be it paint, insulation, or a liquid-applied water-resistive barrier (WRB). There are labor savings with liquid WRBs but not, in my experience, with the compatible window flashings that take considerably more time to install compared to their than tape counterparts. Overall, it’s a trade-off, and a decision based on quality rather than efficiency. When installed correctly, a liquid-applied WRB can provide a tougher and tighter air and water barrier—especially the commercial grades, which go on thicker (think costlier) and last longer in laboratory testing.
Let’s look at the more popular spray and roll-on materials on today’s market:
The PolyWall Blue Barrier 2300 Liquid Wrap is a spray-applied, fully adhered, permeable air and moisture barrier that sticks to wood sheathing and concrete. A hybrid of silicone and polyurethane technologies, the material is said to bring together the most desirable features of each, creating a durable, high-quality product. Liquid Wrap adheres to both porous and nonporous substrates. The system can secure the gap between framing and foundation better than sill-sealer so that no air or insects can get through this usually weak joint. PolyWall offers a compatible 2200 Joint Filler (caulking) and a roller-smeared 2400 Flash ‘N Wrap to use around openings. The Liquid Wrap covers between 300 and 400 sq. ft. per 5-gal. bucket.
PolyWall Building Solutions sells a 5-gal. bucket for $600 or $1.71 per sq ft.
Air-Bloc All Weather STPE is another single-component, moisture-cure, silyl-terminated polyether (STPE) water-resistive air barrier made by Henry, a company that’s been making waterproofing materials for roughly a century. Henry says Air-Bloc is rain-ready within 30 minutes of application, helping to reduce potential weather delays. Its hydrophobic nature also means it won’t wash off…
Get building science and energy efficiency advice, plus special offers, in your inbox.