Issue link: http://digital.canadawide.com/i/178290
VanDusen Botanical Garden Visitor Centre by Lauren Kramer he 55-acre VanDusen Botanical Garden in Vancouver is a favoured destination for Lower Mainland residents and tourists alike. Until recently, though, its hidden entry pavilion meant that many would pass it by without even knowing it was there. That was just one of its problems. Built in the 1970s, VanDusen's dated facilities had inadequate space for classrooms given the demand for educational programs. It urgently needed an update that would provide increased lexibility of space, more visibility from Oak Street, larger classroom facilities and a new food-service facility. "In the early stages, the intention was to demolish some of the existing administration buildings and re-house administration in a new building," says Jim Huffman, associate principal at Perkins + Will Canada Architects. It took months of deliberation before the client agreed instead on a different site on the southeast corner of the lot, adjacent to the lake and the road. This site, which was previously the Holly Garden, allowed for a prominent and visible building. On October 23, 2011, after a year and a half of construction, staff at VanDusen Botanical Garden applauded the opening of the new Visitor Centre, its luid, elegant architectural form inspired by a native orchid. The new centre contains classrooms and lexible meeting space, three featuring moveable walls that allow the space to be expanded and contracted in size as necessary. There's a new food-service facility, a 1,500-square-foot garden shop with indoor and outdoor spaces, a library and a Discovery Room that will display plant-focused educational exhibits. T A heavy facade was developed on the busy eastern street side of the building, utilizing pigment and cement in sculptural rammed earth walls. Washrooms and secondary spaces were located on this side to act as a sound buffer, while the glazed western garden side houses the classrooms, their large, 12-foot roof overhang offering protection from the rain so that learning can take place indoors and out, year round. The site grading reveals views to a previously hidden stream as well as vistas of the lake and wetlands. Esthetically, the new Visitor Centre is so striking, it's hard to miss. The building is organized into multiple petals of undulating green roof along stems of rammed earth, connected by a vegetated land ramp. The prefabricated roof panels were developed with Rhino and Revit software and are composed of unique, curved glulam beams. Of the 20,000-square-foot roof, 16,000 square feet is planted with fescues and native bulbs to resemble a meadow. The remaining square footage is designed to collect and ilter rainwater, storing it in an underground cistern for the building's non-potable water requirements. One of the primary goals in the new Visitor Centre was to address the esthetics of sustainable design. "This building pushes sustainability to its present-day limits," says Huffman, whose team followed the materials and design criteria of the Cascadia Green Building Council's Living Building Challenge. The challenge pushes buildings to achieve the highest measure of sustainability based on current available technologies. That meant net-zero energy and water consumption annually. At the centre, iltered rainwater is used for the building's grey water requirements, and black water is treated in an on-site bioreactor. A geothermal exchange system, solar hot water tubes and a solar photovoltaic array work together to achieve the goal of net-zero energy expended. Natural ventilation is achieved by way of a solar chimney composed of an a glass oculus with operable vents and an aluminum heat sink, which converts the sun's rays to convection energy. The summer sun shines on darker surfaces of the heat sink to further enhance ventilation in the centre, and the construction project was carbon neutral. Materials used in the building's composition are simple and low-emission: concrete loors, aluminum and glass windows, and rammed earth on the eastern side. But narrowing them down was a complex process, Huffman concedes. "We had to do a lot of research on the appropriate materials to use, because the Living Building Challenge's Materials Red List vetoed the use of many materials including any vinyl, cadmium or heavy metals in the construction," he says. "The Visitor Centre represents a huge step forward in sustainability, but it wasn't easy to achieve." For the construction team, it was challenging using unfamiliar materials and construction methods as well as Above: The Joseph Segal Family Foundation Atrium and the atrium Oculus. Right: The entrance facing north. All photos: Raymond Chan. VanDusen Botanical Garden Visitor Centre p.60-63VanDusen.indd 61 3/26/12 2:58:52 PM