Photos courtesy New Energy Works Timberframers
The build
The company designed the single-level building to house NEWwoodworks in 1208 m2 (13,000 sf) and offer storage/shipping for its sister company, Pioneer Millworks, in the remaining 743 m2 (8000 sf). The project used 95-mm (3 ¾-in.) CLT wall panels and 78-mm (3 1/16-in.) CLT roof panels, all averaging 2 m (8 ft) wide x 11 m (38 ft) long, around Douglas fir timber rafters and posts. This design pushed the flexibility of structural CLT walls, with the incorporation of a timber frame allowing the panels to be oriented horizontally at roughly half the usual thickness. Overall, the combination resulted in less CLT materials and fewer timber components (such as top plates and common rafters) in the timber structure, resulting in lower costs, less waste, and faster construction.
The NEWwoodworks shop area employs glulam timbers ranging from 222 x 343 mm (8 ¾ x 13 ½ in.) to 127 x 457 mm (5 x 18 in.) for a series of trusses, which join to single and paired solid Douglas fir posts. A clear 28-m (91-ft) expanse in the Pioneer Millworks storage area was created with 273 x 724-mm (10 ¾ x 28 ½-in.) glulam timbers employed in two bridge trusses with heavy steel connectors and plates. To develop the necessary stability, the CLT wall panels were fastened to the exterior of the Douglas fir posts, providing lateral (i.e. shear) strength while the roof panels act as a diaphragm tying the structure together. Ultimately, all of these forces are transferred down to the foundation. Hold-down straps at the exterior posts and plates along CLT walls complete the mass-timber structure.
Connection types in this project included:
- panel to post;
- panel to rafter;
- panel to panel (both wall to wall and roof to
roof); and - roof panel to wall panel.
In this instance, 8-mm (5/16-in.) self-tapping washer-head screws connect the spline-joined horizontal wall panels and half-lap roof panels. Fasteners were typically at 203 or 305-mm (8 or 12-in.) centers and varied in length based on the connection type. The hold-down straps were a plate to the mudsill using eight 13-mm (½-in.) lag bolts at 1 m (4 ft) on center (o.c.).
