The green scene

Making sense of the sustainable building certification programs on the market

By Sue Pekonen and Joseph Caouette

Sustainable buildings usually have three main goals in mind: reduce environmental impact; ensure long-term economic viability; and contribute to the health and social well-being of everyone who interacts with the building.

Certification programs like LEED, Green Globes and Living Building Challenge all embrace these goals. But that is where the similarities end. Each program offers a distinct approach to sustainability projects, and tracking the differences between certification systems can be more than a little confusing for builders and owners. Why does one project use LEED while another chooses Green Globes? What kind of projects should be tackling the Living Building Challenge? Everyone may agree on the goal of making a more sustainable building, but there are a number of different routes projects can take to get there.

Diversionary tactics

The construction industry is adopting an increasingly sophisticated approach to waste diversion in order to lighten the load on the province's landfills

By Joseph Caouette

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Two points does not always amount to much. It can be a single dunk in a basketball game, or the word "so" in Scrabble. But on a large construction project, two points can represent tonnes of waste saved from the landfill.

There are 110 points up for grabs on the LEED certification checklist, and just two of those points relate to waste diversion: one for diverting 50 per cent of project waste, and another for diverting 75 per cent. Yet, mixed construction and demolition (C&D) waste is usually a serious issue for any city. Current figures are not readily available, but Statistics Canada estimated C&D materials accounted for 25 per cent of the province's municipal solid waste less than a decade ago. As recently as 2012, 20 per cent of the waste sent to Calgary's landfills was still generated by the C&D sector. Diversion may have a modest impact on the scorecard, but its importance to the environment is huge.

A rainbow of roofing

Blue, white and green roofing innovations promise to make buildings more, well, green

By Melanie Collison

Photos by R.Thornton (Alberta Ecoroof Initiative roof)

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In 1875, Fort Calgary was the city's first public building with a living roof. The prairie sod soaked up rainwater, kept the fort cooler in the summer, and trapped in heat in the winter.

While it's been around for 150 years, green—or living—roofing is a trend that's been slow to develop. Alberta also hasn't seen a rush towards white (reflective) or blue (stormwater collecting) roofing, either, despite the industry's push to become more environmentally sustainable.

Compared to traditional flat commercial or industrial roofs, all three roofing systems have pluses and minuses.

A white roof adds points towards a building's LEED score and reduces the need for air conditioning, which works well in the southern U.S., where the cooling-to-heating ratio is 80:20; however, the heating costs under a white roof clearly rise in Canada, where the ratio is more like 20:80.

And there's another concern: "White [roofing] is often single ply and very vulnerable to hail damage," explains Kerry Ross with IBI Group Architects.

A blue roof has real appeal where stormwater management is a concern, as it is in most of Alberta.

As the first Canadian municipality to adopt a sustainable building policy, Calgary has been requiring stormwater management on city buildings for a decade. "The vast majority of projects are done by private industry and private consultants, so we encourage efficient management of stormwater," says Justin Pockar, energy and environment coordinator with the City of Calgary.

The city has been working with SAIT to develop a rainwater-harvesting handbook that spells out how and why to design and install a rainwater collection system. Blue roofing is certainly a step up from a simple cistern collection system, but there are still concerns.
"Blue roofs will address stormwater well if they're designed well, but they don't offer thermal protection, amenity space or preserve roof membranes," Pockar explains. "It's an economical solution if you're just building a better standard roof. They're cheaper than green, but slightly more expensive than a regular roof because you have to beef up the structure."

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