A roof that needs replacing can be seen as an unwanted expense or as an opportunity to improve a building’s efficiency and durability.

When Polaris Realty realized its building at 2700 Matheson Blvd. East in Mississauga needed some rehab—including a new roof—the company decided to go for Leadership in Energy Efficiency and Design (LEED) certification for existing buildings. Administered by the Canada Green Building Council (CaGBC) the LEED rating system is an effective, if costly, way to guarantee that a project meets green building standards.

LEED-certified design and construction along with a roof that reduces the Heat Island (HI) effect could win developers up to five LEED points (a project with 40 points is certified). So Polaris decided to work with Tremco, a local manufacturer, and Semple Gooder, a local contractor to install a LEED-worthy roof. Tremco used mostly recycled materials and reused the existing insulation. They also recycled the old ballast, minimizing the amount of waste going to the landfill.

In fact, Mike Taylor with Tremco says the only thing they did throw out was the old roof membrane, which was in no shape to be salvaged. “I have a piece of it and it’s rotted through,” he says. With roofing, Taylor says there are only a few critical goals: make it watertight and make it last. The existing roof was doing neither. It was an inverted loose-laid EPDM that lasted 20 years but had been plagued by leaks for the past five years. “It’s like a pool liner,” says Taylor. “It shrinks over time, vibrates on the concrete and wears out.”

Tremco replaces that membrane with the Tremco TRA-LRM cold-applied roofing system, a dual layered waterproofing system which Taylor says can last as long as the building.  “Roofing is an expensive proposition and you want something that will last as long as possible,” says Taylor. It may have cost more than a traditional roof, but the TRA-LRM membrane will significantly increasing the life-cycle of the roof.

It also reduced the building’s HI effect (an urban heat island is a metropolitan area which is significantly warmer than its surrounding rural areas). The new roof, made of white calcite, a reflective stone, reduced the temperature on the roof by 20 degrees—“and that was in April,” says Taylor, “not during the height of summer.”

Thanks, in part, to this new roof, Polaris has a LEED-certified building. And in June 2009, the CaGBC announced the details of its LEED Canada for Existing Buildings: Operations and Maintenance 2009 (LEED Canada EB: O&M) program. This means that Polaris can continually assess the environmental performance of its roof and building with LEED guidelines as a benchmark.

Download the entire case study here.