What is it?

As vertical variants of green roofs, green or living walls are also becoming increasingly common in the urban landscape. These phytotechnologies are inspired by traditional structures like windbreak hedgerows in the countryside and the walls of ivy that adorn many façades.

What is it used for?

These walls may be freestanding, meaning that they are selfsupporting. One example is the living sound barrier developed in Quebec by scientists at the Montreal Botanical Garden. Set up along our roads, these barriers reduce traffic noise, wind speeds and dust dispersion.

For their part, living walls attached to buildings have benefits comparable to those of green roofs. Outside, they capture rainwater and evacuate the heat from building façades. Inside, they humidify and cool the air, absorb pollutants and improve the working environment. Moreover, they are graffiti-proof!

How is it made?

Living sound barriers are built “sandwich-style.” Two membranes supported by a rigid structure surround a layer of soil in which vegetation is planted, keeping the soil in place. The plants green the structure to the point of hiding it entirely. The resulting mass of vegetation is a highly effective noise abatement system.

In the case of walls attached to buildings, a more complex technology is used. Water fortified with nutrients percolates from the top to the bottom based on a programmed cycle. Of course, as with any phytotechnology, it is important to select plants that are well suited to the environment.

In Quebec

Created by a researcher at the Montreal Botanical Garden, living sound barriers of willow shrubs are sprouting up along highways in the Greater Montreal area.

The living wall at Desjardins Group’s head office in Lévis is one of the tallest in the world. A true work of art, it stands 65 metres tall and comprises 42 varieties of plants and 11,000 individual specimens!1

In the world

The vertical garden created by architect Alfredo Bollani is simply breathtaking. It covers a façade exceeding 1,000 m2 in a shopping centre in Milan, Italy. Bellissimo!2 The gardens created by architect Patrick Blanc, like the one at the Caixa Forum in Madrid, Spain, are also masterpieces.3

This plant wall at the University of Guelph-Humber is integrated into the building ventilation system. It helps remove up to 47% of pollutants.