From concrete to living garden, the Toronto City Hall podium roof, where visiting dignitaries were once welcomed at the “front door” of the Council Chambers, is now a public green roof garden.
Approximately 3,250 m2 (35,000 square feet) of concrete on the podium roof has been transformed into living vegetation to reduce the building’s environmental impact and for residents and visitors to enjoy all year around.
New landscaped gardens, courtyards, terraces, furniture and walkways provide unique views of downtown from this urban oasis in the heart of the city.
Come see how Toronto’s iconic City Hall continues to inspire in this age of environmental sustainability with its green roof structure that comes with a state-of-the-art irrigation system, and is also the city’s largest publicly accessible green roof!
As well as performing regular, state-of-good repair on the City Hall roof membrane, as part of the Nathan Philips Square Revitalization Project the City has installed an extensive green roof with 3,250 square metres (35,000 square feet) of vegetation).
The podium roof has been planted with a pre-vegetated, modular green roof system.
Modular systems are essentially trays of vegetation in a growing medium that are grown off-site and seamlessly installed on rooftops.
A diversity of plant species, grown regionally, has been selected for the City Hall podium roof for their seasonal colour and ability to withstand difficult rooftop conditions.
As part of the Nathan Philips Square Revitalization Project, the City has installed an extensive green roof with approximately 3,250 m2 (35,000 square feet) of vegetation on the podium roof of City Hall.
A diversity of plant species, grown regionally, has been selected for the City Hall podium roof for their seasonal colour and ability to withstand difficult rooftop conditions.
The podium roof has been planted with a pre-vegetated, modular green roof system that is essentially trays of vegetation in a growing medium, which have been grown off-site and seamlessly installed on the rooftop.
This system offers several benefits to this project over other technologies. The pre-planted trays were assembled on the finished roof assembly with the plants already established, making for a “finished” looking roof from day one. The units were designed for rapid assembly, shortening installation time.
Once in place, the top portion of each tray was removed exposing two to four inches of soil, allowing the plants to spread roots between trays, making a unified field of plants, and tying together the entire system.
Over the life of the roof, if roof maintenance is required, individual trays can be lifted off the membrane, repairs completed, and the plants put back in place, with little disruption to the plants themselves.
The plants for the Podium Roof Garden are a mix of various species of sedum and taller bulbs, perennials, and grasses, which are composed in East-West “drifts” of colour and shade tolerance, ranging from yellows and oranges at the sunny Southwest to purples and reds at the shady Northeast.
The garden is a mix of sun and shade tolerant sedums and perennials grown in a modular pre-vegetated tray system. The species range from grasses such as Feather Reed Grass and Little Bluestem to flowering Coneflower and Asters. All planting is united by a sedum mix ranging in colour from blue to green to burgundy. The trays are arranged in linear fields of purple, pink, yellow/orange and green, which correspond to the varying site conditions of full sun to shade and will change colour seasonally in this dynamic landscape.
The main planting areas ring the City Hall towers, with a paved courtyard framing the Council Chamber and an open, paved terrace at the Southeast. A circular tree planter featuring three Kentucky Coffee trees and aromatic shrubs provides shade and seating for the terrace that serves as a public gathering area.
A series of stone walkways around the perimeter completes the composition, along with smaller East-West connecting pathways running through the gardens.
From concrete to living garden, the City Hall podium roof, where visiting dignitaries were once welcomed to this great city, revived and re-introduced as the new Podium Green Roof – Toronto’s largest publicly accessible green roof.
Included in this new urban oasis in the heart of the city are landscaped gardens, a courtyard framing the Council Chamber, a podium terrace and new walkways, to be enjoyed by residents, visitors and downtown workers.
Benefits of a green roof on the podium of City Hall: