Green architecture – Semiahmoo Public Library green wall

In one of our previous articles we already wrote about a green wall built on PNC Financial’s headquarters, and in this article we’re going to write about the currently largest and most biologically diverse outdoor green wall in North America. Designed and planted by Green over Grey designers, it is covering the Semiahmoo Public Library and RCMP Facility in Surrey, Canada.

The unique design has nearly 279 square meters (3,000 square feet) and consists of over 10,000 individual plants representing more than 120 unique species. It includes ground covers, large perennials, shrubs and small trees.

“This will be our first large-scale green wall in Surrey”, said Mayor Dianne Watts. “It will be a beautiful living work of art that will cover the existing concrete wall and provide many environmental benefits, including saving energy, reducing greenhouse gas emissions and creating a new ecosystem in the heart of Semiahmoo.”

The technology being used is soil-free, and the plants receive water and nutrients from within the vertical support instead of from the ground. It closely mimics how plants grow vertically in nature such as on cliffs, bluffs, tree branches or next to waterfalls. The folks from Green over Gray claim their system is much better than modular systems with soil because their system weights up to 10 times less, and it doesn’t require significant amount of time to grow onto structure or damage the structure it is built on like some of the wall climbers.

“The large diversity of plant species chosen creates a balanced ecosystem that is an urban oasis for bees, butterflies and hummingbirds”, said Patrick Poiraud, Principal at Green over Grey – Living Walls and Design, the Vancouver-based company designing and constructing the wall. “The living wall helps to insulate the building, purify the air and transforms the grey concrete into hundreds of shades of green.”

Aside air purification and reduction of the heat-island effect, the waterproof living wall panels and the exterior envelope are separated by a layer of air, allowing the building to ‘breath’. The system is very similar to rain-screening technology because keeping rain off the building while still allowing moisture to escape. Covering an exposed vertical surface with a green wall shields it from precipitation and wind as well as from harmful UV radiation and corrosive acid rain. The walls also provide additional sound and heat insulation.

“The initial inspiration for this garden came from the artwork of the Coast Salish (including Semiahmoo) First Nations People”, said designer and artist Mike Weinmaster of Green over Grey.