John Brooks highlights features of his product, ThermalBuck, with JLC. Comprised of type XIV EPS encased in a polyurethane/polyurea blend coating, ThermalBuck offers a smart alternative to site-built wood bucks. In addition to solving the problem of thermal bridging, it eliminates the potential for warping and shrinking associated with wood bucks, which may cause leaks in the multiple layers of flashing tape. Pieced together in the rough opening rather than being pre-built on the ground, ThermalBuck is lightweight and durable. It’s available in 8 foot lengths, with 5 standard size depths matched to the exterior insulation/rainscreen thickness depths. At the sill, its extruded profile has a 1/32″ slope, which acts as an integrated sill pan—the back dam is created when the interior is sealed. View manufacturer videos.