When Port Coquitlam became the first municipality in Canada to mandate green roofs on large commercial buildings in 2006, developers were skeptical. The zoning bylaw required green roofs on all new buildings of more than 5,000 square metres (53,281 square feet).
Now, however, the 650,000-square-foot Freemont Village in Port Coquitlam by the Onni Group is seeing both a large Wal-Mart and a new Canadian Tire store outfitted with green roofs - and they are not the first or the last.
Onni development manager Mike Mackay said that the $1 million Wal-Mart green roof, covering 151,300 square feet, cost three times more than a conventional roof. But McKay said the extra cost should pay off in both public relations and long-term energy savings for clients. The Wal-Mart roof is planted with a variety of local and foreign plants, including California poppy and Arctic bluegrass.
McKay said that, aside from Wal-Mart and Canadian Tire, three more buildings in the big-box Freemont Village could have green roofs installed.
According to city officials, the main purpose of the green roof policy is to obtain environmental benefits including reducing storm water run-off, improving building thermal performance and energy consumption and reducing the urban heat island effect. The city estimates that the higher cost of green roofs are normally recovered within the first two years of building operation, while the energy savings and storm water reductions continue for the life of the building.
Laura Lee Richard, director of development services for the City of Port Coquitlam, said there is a variance policy that allows developers to not include a green roof if other energy-saving and environmental issues are addressed. For instance, a larger unheated industrial warehouse project required a green roof just over the office area of the building, she said.
Green roofs are not required on smaller commercial and industrial buildings, she added. However, resistance remains. Some developers cite the ongoing maintenance costs associated with green roofs, while roofing contractors worry about repairing leaks that may be buried beneath soil and plants.
from Western Investor January 2012
