Weyerhaeuser’s Flak Jacket is an intumescent fire-resistant coating for Trus Joist TJIs. In multifamily buildings, it provides a one-hour fire rating for floor and ceiling assemblies with one rather than two layers of 5/8-inch drywall. In single-family construction, it gives I-joists the burn equivalency of solid 2x10s, a requirement for unfinished basements in some jurisdictions that have adopted the 2012 IRC. Of course, the first thing we noticed is that the flanges are only partially coated. No problem, says the company: The coating swells when heated, covering enough of the flange to achieve the needed fire rating. Expect to pay about 50% more than for the company’s standard I-joists.
Weyerhaeuser, 888/453-8358, woodbywy.com.
