“In cities across North America, the low-density sprawl that has characterized development since the mid-20th century is giving way to a growing landscape of mid-rise buildings; five- to six-storey structures that are more environmentally sustainable and cost effective because of their increased density—while still blending with existing neighbourhoods and helping to create livable communities that accommodate growing urban populations.
The migration of residents from rural areas to cities has been a global trend that continues to gather momentum. In Canada, the 2011 census confirmed that, for the first time, more than 80% of the population lives in urban areas. In Metro Vancouver, the population is expected to increase by more than 50% to a total of 3.4 million by 2040.(1)
In anticipation, many unicipalities in B.C. have adopted policies that aim to accommodate growth through the densification of already developed areas; for example, by rezoning single-family residential neighbourhoods to permit mid-rise residential construction.
At the time of its inception in 1941, the National Building Code of Canada (NBCC) permitted wood buildings of up to 22.5 metres in height, which corresponds to eight storeys. This was a relatively common height for wood buildings of the day and many examples remain. However, subsequent changes to the code reduced the maximum allowable height to four storeys. This was the limit in British Columbia until 2009 when, after a comprehensive consultation process, the B.C. Building Code, which is based on the NBCC with modifications, was changed to permit six-storey woodframe residential buildings.
Put in a global context, five-storey wood-frame buildings are permitted in the U.S. under the International Building Code; five-and-a-half storeys if the project has a mezzanine and six for an office occupancy. In the United Kingdom and Austria, there are examples of eight-storey buildings made from cross laminated timber (CLT) and, in 2012, a ten-storey CLT building was completed in Australia.
Since the B.C. code change, five- and six-storey wood-frame buildings have proven popular among developers, architects and contractors, who see them as a way to increase density at lower cost while reducing environmental impact. In less than five years, the number of mid-rise projects planned, underway or completed has risen to more than 150.” Read the full case study.