The boxy, 1970s Old Main academic building at the center of Thompson Rivers University’s (TRU’s) campus in Kamloops, British Columbia, lacked the space and dignitas needed to house a law school. That changed when the Toronto-based firm Diamond Schmitt Architects (DSA) capped the building with a two-story, 45,000-square-foot addition and undulating timber roof that rivals the mountainous setting.
The 400-foot-long roof transformed this insipid building into a centerpiece for the 250-acre campus, which overlooks the confluence of the north and south branches of the 304-mile-long Thompson River.
Timber was chosen for the roof because of British Columbia’s strong logging industry and the First Nations’ long use of wood in construction. The roof’s glued-laminated (glulam) timber frame is supported by wood purlins made of trees that were killed by the invasive pine beetles that are ravaging forests throughout the province. “It’s a very green and sustainable way to reuse something that is [otherwise] a waste material,” Schmitt says.
The shell of the roof and building addition had to be completed during the summer, when there were fewer people using the building. To meet the tight deadline and $6.9 million project budget, the team designed the roof to be prefabricated from 92 panels, curved in profile and rectangular in plan.
The roof’s geometry was achieved using Rhino and AutoCAD. Vancouver, British Columbia–based structural engineer Fast + Epp worked with architectural structures firm StructureCraft Builders, in Delta, British Columbia, to design and manufacture the prefabricated panels.
Some of the panels have a unique form, but approximately 60 percent share the same geometry. StructureCraft bent the glulam beams using a template to frame each panel and then infilled the frames using the straight wood purlins. Each 12-foot-wide-by-36-foot-long panel weighs about 4,000 pounds.
The panels were transported to the site in 42 tractor-trailer loads and then hoisted atop 5-inch-diameter structural steel columns along the building perimeter and down the roof’s centerline. The panels, which locked into place like puzzle pieces, were bolted together to form the continuous serpentine structure. The installation was completed in seven weeks.
An insulating layer with an R-value of 60 covers the panels, which is then topped by a plywood roof deck and flexible EPDM (ethylene propylene diene monomer) membrane that contours to the roof’s curves. The roof eave, clad in weather-resistant cedar, cantilevers 5 to 13 feet past the building’s façade. Inside, the undulating ceiling is covered by medium-density fiberboard acoustic panels with a maple veneer. The custom-fitted panels have a fire-retardant treatment to meet the local fire safety code.
Classes in the expanded building began this January.
The renovation did more than allow the university to reuse an existing building, Schmitt says. “Suddenly this unpleasant box was turned into something that has a more iconic presence on the landscape and a more positive contribution to the campus.”
Watch Schmitt discuss how the form of the renovated building was developed: