May 22, 2007

CAT O'NEILL

Living walls, such as this one in Toronto's Robertson Building, are becoming increasingly popular.

Climbing the walls: plants as structure

SAUL CHERNOS

correspondent

TORONTO

Walk into the Robertson Building, an unassuming, century-old brick structure at 215 Spadina Ave. in downtown Toronto, and you could be forgiven for thinking you’ve stepped into the Amazon rainforest.

By every outside appearance, this five-storey red brick office complex fits discreetly into the Fashion District. However, the foyer is a world unto itself.

Designed and built by Air Quality Solutions of Guelph when the building was restored, the indoor living wall features a mix of native and exotic indoor species snuggled into a covering of thick, artificial planting material that allows water to filter through the plant roots on a vertical plane.

“We look at the natural environment as a very important part of the indoor landscape of our buildings,” says Beth Anne Currie of the Urban Space Property Group, which owns and operates the building.

Currie says plants help clean and detoxify the indoor air and have a soothing effect on building occupants.

Stephen Peck, executive director of Green Roofs for Healthy Cities, says green wall systems come in many shapes and sizes, each with a unique design and assortment of vegetation, and can be located both on the exterior or interior.

“There are many kinds of green roofs,” Peck explains. “They can be adjacent to the wall of a building, on the wall of a building, or within the wall of a building. You can have a stand-alone structure, like a grid, that allows plants to grow six inches from the building.

“You can have a water-based system that allows plants to grow right up beside the envelope.

“And there are also ‘living walls’ which are in fact part of the cladding of the building and have pockets in which plants can grow right in the wall itself.”

Peck says green walls share many attributes with green roofs in that they enhance energy efficiency and aesthetic appeal and clean the air.

Green walls can even be designed to grow fruit or house actual habitats.

For churchgoers at St. Gabriel’s Passionist Parish at 670 Sheppard Ave. E. in Toronto, an indoor living wall located in near the entrance serves as a spiritual conduit, helps protect the environment, and was among many factors that helped earn LEED Gold from the Canada Green Building Council.

“It kind of represents the Garden of Eden,” says Rory O’Brien of Faith and the Common Good, an interfaith nonprofit group that works with religious organizations on issues such as environmental stewardship.

“As people come into this place of worship, they see the green wall and are reminded of the importance of nature.”

Brad Bass, an adjunct professor at the University of Toronto who works with the adaptation and impacts research division of Environment Canada, says green walls pose unique challenges for designers and builders.

While a wall covering can help keep water away from the siding, wind problems can arise at higher elevations.

“It’s an engineering issue,” Bass explains.

“There’s no one way of doing it. It depends on how you want to put the plants on the wall.”

Windows and shading also need consideration.

“It’s a good idea to use green walls to give some shade to the windows, but you don’t want to block all the natural light either because then you have to turn the lights on.”

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