Saanich Voice Online looks at green roofs

Up On The Roof
P.C. King, Citizen Journalist

In earlier times the area known as Central Saanich was considered the breadbasket for what is now the Capital Regional District (CRD).

Today, the breadbasket for our region could extend to the rooftops, according to Saanich Councillor Dean Murdock. By developing rooftop gardens, communities could begin utilizing large areas of ‘empty space’. Although rooftop gardening is relatively new to the Saanich Peninsula, green roofs are not a new idea to communities around the world.

Murdock believes that rooftops are one of the best places to grow crops in Saanich. Murdock would like Saanich Council to introduce rooftop gardens as an amenity included in part of the guidelines for large-scale developments.

“We can turn acres of asphalt into green space and vegetable gardens,” Councillor Murdock stated. “Green roofs allow urban residents to grow their own food, and help reduce our carbon footprint.”

Councillor Murdock is not alone. A sustainable, food producing rooftop garden, or greenhouse, is a concept being considered all over the world.

In Montreal one company is growing crops of vegetables and herbs in a vast greenhouse built on top of an office building. In Chicago, the City Hall grows 20,000 plants (over 150 varieties) on their 20,300 square foot rooftop. The Urban Habitat Chicago (UHC) works diligently with the City Hall Planning Department before any of their rooftop projects begin. Permits are issued only for projects that meet strict standards and reflect careful architectural planning by certified structural engineers. The screening, planning, and building process is thorough… leaky condos need not apply.

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(website of Chicago City Hall)

Rooftop gardening is different from garden allotments at ground level, and is not a simple backyard vegetable patch or a weekend do-it-yourself home handyman project. However, a rooftop garden is possible for private yards and home owners and not just large development projects.

Green roofs can be installed on various types of structures, flat or sloped. Extensive green roofs require less soil (1-5 inches) where intensive roofs can be deeper and allow for more plants.

To add a rooftop garden to an existing building the support structure would need redesigning to meet the different load requirement of either an intensive or extensive rooftop garden. Local green roof expert Kevin Kersten, shares his knowledge of these issues on his website Kevin and Karina’s business, BC Greenroofs Consulting, was nominated for an Ecostar award in 2010 for their goal of preserving the natural environment and improving the quality of life. They assisted with the development of a small green roof on the vegetable market stand located at the Vantreight Farm.

Although installing green roofs on existing buildings may be more challenging, for new buildings the engineering and architectural aspects can easily be incorporated at the initial planning stage.

As an amenity for new developments, our municipalities are searching for ways to develop more green spaces. As suggested by Councillor Murdock, municipalities would be addressing this need by encouraging projects such as green roofs.

As Kevin Kersten points out, “It is not complicated but one must consider the things that matter—attention to detail, safety…and what it will look like in the future…with some creativity green roofs are not only for the big projects anymore. With our concept of going green, a small step at a time, you can enjoy a green roof in your own back yard.”

Rooftop gardens are not (as yet) going to displace agricultural or rural landscapes. They will not threaten the need for farmers or farming communities. The benefits include living green spaces, small scale food production, insulating properties for the building, and practical storm water management with drought-tolerant native planting.

With careful planning rooftop gardening is not far “outside the box.” Municipalities can begin working with consultants such as BC Greenroofs to initiate the future development of agricultural use of the vast empty space on your roof.