Longevity in a Challenging Prairie Climate

Calgary, AB | EcoLogic Horticulture

Built for a Demanding Climate

In Calgary, Alberta, green roofs experience some of the most challenging rooftop conditions in North America. Intense UV exposure, drying winds, freeze-thaw cycles, and prolonged winter conditions can all impact long-term plant performance.  More than ten years after installation, City Centre Tower continues to demonstrate how a green roof designed for regional conditions can mature successfully over time.

Installed between June 2015 and April 2016, the 34,000 square foot LiveRoof system spans four rooftop levels on the downtown corporate tower. The project was part of the building’s broader LEED Platinum sustainability strategy and combined vegetated roofing with reflective pavers and rooftop amenity spaces.  Designed by Zeidler Architecture with landscape architecture by Matrix Landscape Architecture, the project integrated environmental performance goals with accessible outdoor space for building occupants.

A Roof Designed for Function and Visibility

The City Centre Tower green roof was designed to serve several purposes simultaneously. In addition to contributing toward LEED Platinum certification, it helps manage stormwater, reduces rooftop heat gain, improves aesthetics, and provides amenity space adjacent to conference areas on Level 2.

The project utilized the LiveRoof® Standard 4.25″system with RoofEdge® Mill finish edging and RoofStone® integrated pavers. The vegetated areas were planted with Sedum varieties selected specifically for Calgary’s prairie climate.

Unlike many commercial green roofs that are rarely seen after installation, portions of the roof remain visible from Calgary’s Plus 15 elevated pedestrian network. The downtown walkway system provides views into the rooftop landscape from surrounding buildings, allowing the green roof to become part of the visual urban environment rather than simply an unseen sustainability feature.

Performance After Ten Years

For EcoLogic Horticulture Ltd., the regional LiveRoof® grower, City Centre Tower remains one of the company’s most referenced projects because of how consistently it has performed over the past decade.  The roof was designed as a non-irrigated system in a full-sun environment—conditions that can quickly expose weaknesses in plant selection and rooftop design. Yet more than ten years later, the roof continues to maintain strong vegetative coverage across all four roof levels.

According to EcoLogic Horticulture, the project still looks as successful today as it did when it was first installed, reflecting the importance of matching plant material to regional rooftop conditions.  The project also highlights the value of regional horticultural expertise. As the only green roof grower on the Canadian prairies specializing specifically in rooftop plant production, EcoLogic has spent years evaluating how different plant varieties respond to Western Canada’s environmental extremes.

Project Details

• Project: City Centre Tower – Calgary, Alberta
• Installation: June 2015 – April 2016
• Green Roof Size: 34,000 sq. ft.
• Roof Levels: 4
• System: LiveRoof® Standard 4.25″
• Accessories: RoofEdge® Mill Finish and RoofStone® pavers
• Visionary: Viktor Kallos
• Architect: Zeidler Architecture
• Landscape Architect: Matrix Landscape Architecture
• General Contractor: PCL
• Installer: Skyline Building Envelope Solutions
• LiveRoof® Grower: EcoLogic Horticulture Ltd.

Looking at Longevity

Projects like City Centre Tower help shift the conversation around green roofs from short-term installation success to long-term performance.

More than a decade later, the roof continues to contribute environmental, aesthetic, and occupant benefits while remaining integrated into the architecture of the building itself.  For architects, landscape architects, contractors, and facility managers, City Centre Tower serves as an example of how green roofs designed for climate, durability, and long-term adaptability can continue performing well long after installation.

About This Series