2011 Awards of Excellence: Nathan Phillips Square

Toronto City Hall Green Roof From Above
The project fulfils the original potential of
this space as a public adjunct to the main square,
as a place for ceremony, and as a place
to get up close to the fine detail of the buildings.

Extensive Institutional

Project: Nathan Phillips Square, Toronto, ON – 118,403 square foot green roof
Client: City of Toronto
Award Recipient: PLANT Architect Inc. & Perkins + Will Canada (Architect/Landscape Architects)
Green Roof Designer/Contractor: Flynn Canada / Gardens in the Sky
Green Roof System: LiveRoof
Design Team Collaborator: Hoerr Schaudt Landscape Architect
Design Team Collaborator: Adrian Blackwell Urban Projects
Soils Consultant: Urban Trees + Soil
Heritage Consultant: Blanche Lemko van Ginkel
Structural Engineer: Blackwell Bowick Engineering
Mechanical/Electrical Engineer: Crossey Engineering Ltd.

This project brings new potential to the building and space by offering a garden respite from the harsh concrete downtown environment.
— Mary Tremain, Partner, PLANT Architect Inc.
Flowers at Toronto City Hall Green Roof
The colours on the roof subtly shift from
brighter yellows and oranges in the Southwest
section to reds and purples in the Northeast
– a response to shade and wind conditions
created by the towers.

Revitalizing Toronto’s City Hall

The Podium Green Roof Garden is the first transformation in the competition winning scheme “Agora Theatre” – the Nathan Phillips Square Revitalization. This three-acre upper-level component of Viljo Revell’s 1965 iconic City Hall and multi-level public square was originally conceived as a ceremonial public space, reached via a giant sculptural ramp. The previous concrete space was never successful at attracting the public – it has been closed for over a decade.

The Podium Roof Garden re-conceives this upper level as a vast public park integrated with the existing elevated walkway system, reopening it to the public as a truly engaging 21st Century space. The goal is to reconsider how an extensive 4-6” thick green roof can be an exciting and successful public space providing intimacy, gathering, strolling and wandering within a formally complex, lush and abundant variety of colour and texture that merits repeated visits. It is the largest publicly accessible green roof in Canada and the flagship green roof project for the City of Toronto.

The park consists of a sedum and perennial mosaic perimeter garden, a sparkling black granite paved courtyard that frames the Council Chamber, and a café deck that occupies the prow. The project's tray system allows for easy installation, and facilitates future maintenance. The varying depth of the trays is concealed to provide a seamless surface of planting.

The half-kilometer walk through the Garden reveals the passage of time at different scales. The shade structures mark the movement of the sun and the progression of plant and blossom colours, including something new blooming in different parts of the garden from April to October- marking seasonal change. The initial planting layout is deliberately linear, but the plants will shift and move over time.

The project fulfills the original potential of this space as a public adjunct to the main square, as a place for ceremony, and as a place to get up close to the fine detail of the buildings. It brings new potential to the building and space by offering a garden respite from the harsh concrete downtown environment with places for intimacy and lingering, for lunch and evening strolls, for art installations, and to technically improve the building and environment by contributing to energy efficiency, roof membrane longevity, sound insulation, filtration, storm water management, and habitat creation.

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To view pictures and profiles of the other 2010 winners, please return to our 2010 awards page.

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