April 16, 2010

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Building with robust, high quality materials that are bolted together rather than welded is a better design choice because it makes recycling materials at demolition an easier option.

FEATURE | Demolition/Environmental Engineering

Ryerson University architecture professors present at Canada Green Building Council symposium in Toronto

SAUL CHERNOS

correspondent

Want to enhance your building’s green appeal — and save money? At the recent Canada Green Building Council’s annual symposium in Toronto, two Ryerson University architectural science professors offered advice on salvaging components from old buildings and reusing them in new ones.

“We don’t think of resources which reach the end of their life as having any value — we just throw them away,” said professor Mark Gorgolewski. “We need to think about these materials as a valuable resource.”

Gorgolewski pointed to several examples. When Mountain Equipment Co-op was looking to establish a retail outlet in Ottawa rather than a traditional demolition, contractors carefully removed beams and columns and designed a new structure around their reuse.

When designing with reused components, planning from the very start of a project is essential, Gorgolewski said.

“Because we don’t have standard reused components off the shelf, we have to be more flexible in our design approach and think of our materials as being much more of an input into the design rather than something that we think about in the later stages.”

With some forethought, a significant — even surprising — portion of materials can be reused. Gorgolewski said at the Vancouver National Works Yard, architectural firm Busby Perkins + Will catalogued a range of components from buildings nearby being taken down and achieved a salvage rate of 85 per cent.

“The approach of reusing components is achievable. It has been used quite widely by certain practices, but it’s certainly not mainstream.”

Gorgolewski said the CaGBC’s LEED rating system includes a credit for reuse, yet it’s one of the least-used credits.

“People find it a challenge to identify where we get materials from and how we use them. It’s not like I can go to a store and pick them off the shelf.”

Interested parties can turn to web sites and retail outlets specializing in used or waste materials, can also be creative and look for other sources such as demolition contractors, buildings slated for demolition and salvage yards, Gorgolewski said.

However, sourcing isn’t the only potential barrier. Specifications often require new materials rather than old ones, and clients sometimes perceive reused materials as second-rate even though older materials can sometimes be superior in quality. Design teams sometimes lack experience dealing with older materials, and costs, project duration and design work can all increase.

“Contractors can be frightened of this approach if they’re not familiar with it,” Gorgolewski said. “Strong commitment from the client is needed to make this happen. Flexibility is an important aspect, to not be too rigid in the design so you can accommodate different materials when they’re available.”

Vera Straka, an associate professor at Ryerson said bolted, rather than welded connections and materials which can be easily separated into individual components helps ensure accessibility and facilitate stylistic and other changes later on in a building’s lifecycle.

“We need to look more holistically at the entire sustainable approach to the building design,” Straka said. She added a building’s use can change over the long-term, even in situations where multiple occupants have varying needs, while uses can also shift during the week or even during the day.

Owners and designers also need to plan for eventual disassembly and must therefore ensure the ongoing value of materials.

“If we design a building with durable components, these components can be reused again,” Straka said.

Straka pointed to Canadian Standards Association guidelines, published in 2006, for reusing materials in order to reduce construction waste, improve building longevity and reduce energy consumption. Z782-06, a Guideline for Design for Disassembly and Adaptability in Buildings, addresses concepts, principles and quantifiable metrics and can be assembled into a matrix or checklist to help guide users.

Z783, a follow-up intended to provide a consistent approach to building deconstruction, is slated for release next year.

Michaela Jones, an architect with Paula Bowley Architects in Toronto, helped one client minimize waste from a demolition and rebuild. She says crews needed to gut the building but salvaged what they could, including doors, windows, light fixtures and toilets.

“That proved to be a huge challenge,” Jones said. “The client really wanted to salvage as much as they could, but we ended up spending a lot of time and resources to make that happen. So from an economic point of view it was not necessarily the most efficient way to do things, but you end up with a building that you’re connected to in a different way, and that’s really valuable.”

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