bly layer, acting as a service cavity to run pipes and wires, was installed. (This OSB layer and nonstructural service cavity also were installed on the ceiling. OSB and tape were used as the air barrier at the fl oor.) Finally, the service cavity was covered with drywall. The space’s triple-pane windows include a fi berglass frame with EPS insula- tion inside the frame. The European-style tilt-and-turn windows are installed in the center of the 12-inch wall assembly with a vapor permeable liquid-applied fl ash- ing system. A transition sheet material is embedded into the liquid-applied fl ashing to interface with the 60# paper. “Liquid-applied fl ashing is a standard
detail on all of our projects—big or small,” Hagerman notes. “The products and strategies were designed to become the membrane that wraps inside the window opening and forms a seamless waterproof bucket that remains vapor permeable. Then, the window is installed in the water-
proof bucket and sealed on the inside and left open to the outside, so if and when the window leaks, this moisture can drip onto the sloped waterproof sill and drain out to the face of the rainscreen.” A heat-recovery ventilator (HRV) brings
in fresh air from outside and exhausts inside air over a heat exchanger. It features a carbon-dioxide sensor to ensure it oper- ates at the optimal levels—30 to 300 plus CFM, depending on occupancy. The entire offi ce space is heated and
cooled by a single high-performance duct- less mini-split head. A heat-pump water heater, which is
fairly new to the marketplace, pulls heat from inside the building for domestic hot water. Although the equipment has its drawbacks in a heating climate, Hager- man says it has performed well so far. “One of challenges with an offi ce space is that during the summer it is producing more heat than it needs,” he says. “The heat generated by lighting and eight or