Head and jamb window flanges were taped to the sheathing with Zip flashing tape, then the WRB was installed (left). The Benjamin Obdyke Hydrogap drainable WRB was installed with a 4-inch horizontal (shingle-style) lap and a 6-inch lap at vertical laps. Metal drip cap and Siga Rissan and Fentrim tapes folded onto the sills’ frames (right) were incorporated into the drainable WRB.
A quality dust mask was a must while cutting outside (photo, left). Butt joints for the vertical siding were cut at 30-degree angles (photos, left and right). Field-cut edges do not need to be primed or painted. Also, it’s important to store the Boral flat on a level surface and keep the material clean and dry (installing the product wet or saturated may result in gapping at joint locations).
The siding was installed with 2-inch-long ACQ staples 8 to 10 inches on-center, blind-nailed along the sides (left). Joints were butted together with no gap and were face-nailed with 8d stainless steel ring-shank nails, the nail heads driven flush with the siding’s surface (right). Small dents and imperfections in the stock were either offcut or infilled. Here, the mark above the fasteners was later infilled with auto-body filler, then spot primed and painted.
Jigsaws and drills with Forstner bits (left) were used to cut the siding around penetrations (right). Coarse jigsaw blades lasted much longer than fine ones. Later, the joint was sealed with a paintable, urethane-based sealant.
Due to wind, the HydroGap WRB was installed vertically on the north elevation as the siding was installed. The author nailed by hand near windows to avoid damage to underlying flanges and flashings (the vertical siding butts to the window frame).
At the stair tower (left), the siding was installed with a 1-inch gap between the roofing and bottom edge of siding; note the kickout flashing formed into the roofing pan (right).
With the vertical siding installed, the author snapped lines to help line up the final 16‑inch-o.c. face-nailing. Also of note, the vertical siding lapped over a fiberglass-reinforced plastic protection barrier, Groundbreaker, by Nudo, at grade.