Buildings: Greenland’s Green Roof

The Greenland Group is a company of 30 professionals with its head office in downtown Collingwood, Ontario. It provides services in fields such as municipal infrastructure, land development, environmental management, monitoring and water resources.

Earlier this year, the company renovated a century-old house of 2,500 sq. ft. as well as a 15-year old building of 1,500 sq. ft. that was also on the site. Being a company that promotes conservation and works in the environmental field, Greenland applied green design principles to their own project. Company president R. Mark Palmer, P. Eng., says Greenland’s mission is to provide “innovative solutions with a conservationist ethic that respects the natural environment at the outset, while also complying with best science and proven technologies.”

The renovation’s green features include the use of recycled materials and a state-of-the-art HVAC system. Outside is a permeable parking lot that allows rainfall to soak down into an underground stormwater infiltration system. The infiltration system was constructed in a former in-ground swimming pool.

The 8-ft. x 12-ft. vegetative roof is over the main building’s entrance. The roof was installed by Tremco Canada in exchange for Greenland agreeing to monitor its performance as part of ongoing research into the benefits of green roofs. A wireless weather monitoring system measures the ambient humidity and temperature, ultraviolet light, wind, soil moisture and rainfall. An overflow pipe discharges into a runoff measurement box at ground level. Greenland will determine the correlation between the rainfall and run-off.

The environmental advantages of vegetative roofs are that they absorb solar energy, reducing the heat island effect compared to a standard asphalt roof. By gradually releasing water, they cool the ambient air temperature. They release oxygen into the environment, and they absorb rainfall, thus reducing the load on the town’s stormwater infrastructure.

This year the roof was planted with Periwinkle (Myrtle Vinca), which survived well, but required periodic watering. Next year, varieties of another perennial, Sedum, will be added.

The green roof system includes a waterproofing membrane, root barrier, drainage board, 4″ and 6″ growing mediums, plants and concrete walking stones for maintenance.

Greenland Group design team: Jane Palmer, Jim Hartman, P. Eng., Trevor Boston, P. Eng., Ken Hale.