Living Roofs: The secrets to success

The Helen Schuler Nature Centre

Nestled in the Oldman River valley in Lethbridge, the Helen Schuler Nature Centre [HSNC] has been attracting local and international attention from visitors and living roof enthusiasts since its completion in 2013. On the roof of the building, a 200m2 green roof serves as an outdoor gathering space, living classroom, teems with insect and bird life, and provides a spectacular showcase for landscaping with native species.

By Michael Magnan

A Collaborative Endeavour
Green roofs are technically complex building systems, requiring collaboration between architects, structural engineers, mechanical engineers, civil engineers, landscape architects and specialty consultants. A successful green roof is a combination of engineering, architecture and ecology. A successful green roof also thrives with life — plants bloom, insects buzz, birds chirp, and visitors are astounded to find a living oasis on a roof.

Success requires technical excellence across disciplines, but most importantly, it requires a designer with a comprehensive and nuanced understanding of plant communities. While the selection of plants will vary by region, there are many common factors essential to the design, construction and maintenance of a vibrant living roof.

Commit to success
A green roof is not something that can be designed, constructed and forgotten – it must be maintained for the lifespan of the building. A lack of commitment in the long term is the biggest contributor to the failure of green roofs. Without that commitment from the client and design team, don’t consider a green roof!

The staff of the HSNC, who were also integral members of the project team, were committed from the outset. They envisioned a green roof as an opportunity to enhance visitor experience, to reduce the ecological footprint of the facility, and to demonstrate native plants as a viable alternative to conventional landscaping.

Build the right team
Don’t underestimate the expertise necessary to design a successful green roof. Having a certified Green Roof Professional [GRP], or someone with equivalent training and experience on the team is essential. A certified GRP can assist the consultant team to ensure proper coordination of the various green roof components, and assist the general contractor and their subcontractors in respecting and implementing the overall design intent of the green roof system. The GRP can also work with the team to adapt to unforeseen circumstances that might be encountered during construction.

As we did for the HSNC project, I would also recommend working with a local vegetation ecologist and nursery specializing in native plants to assist in the specification of plants suitable for the particular application and climate.

PROJECT CREDITS
Green Roof Designer / Landscape Architect O2 Planning + Design
Architect Group 2 Architects
Structural Engineer BEI Engineering
Mechanical Engineer AME Group
Electrical Engineer Robertson and Associates Engineering
Green Roof Plant Supplier Eastern Slopes Rangeland Seeds
Green Roof Installer Earthlings
Green Roof System Soprema
General Contractor Dawson Wallace
Roofing Contractor Charlton + Hill

Michael Magnan, M. ARCH, BSc, BCSLA, GHRC GRP is Senior Associate/Landscape Architect with 02 Planning + Design.

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