Jodie Jones discovers the concept behind the Canary Wharf park
Crossrail Place Roof Garden, completed in 2015, was the result of a collaboration between a number of specialist practices and design agencies, brought together by the Canary Wharf Group as part of the Crossrail rail network, which will link east and west London. Trains are not due to start running through the site until 2018, but the garden is already open to the public, and has hosted a series of arts performances and welcomed local schools, who use the space as a resource for extended learning.
Drawing on the heritage of the site as a major historic port, and the maritime nuances of the structure created by architects Foster & Partners, landscape architects Gillespies developed a garden layout divided by a central path into eastern and western sections. This floating walkway is designed to allow for root growth and drainage within the physical constraints of a shallow substrate depth and overhead structures.
“The garden is effectively a waterproofed tray lined with a reservoir and drainage mat,” explains lead designer Armel Mourgue. Given that the growing medium layer ranges from 50cm to 1m, an effective drip-irrigation system was essential. “This was always intended to be a different place,” says Mourgue. “We didn’t want to create another urban park but a unique garden.”
The shell-like roof structure, designed by Foster & Partners, is a 310m-long timber lattice in which the central section and parts of the sides have been left open to allow for natural irrigation and ventilation, while the majority of the panels are filled with ETFE air cushions, which allow in very high levels of natural light while providing excellent insulation.
Overall, the canopy structure helps create a favourable micro-climate that shelters both plants and people from the strong wind turbulence generated by adjacent tall buildings. Despite its sinuous shape, only four of the spruce glulam beams used to construct the canopy are curved. Through most of the canopy, straight beams were connected using a bespoke system of steel nodes to resolve the necessary twist. In those sections without ETFE cushions, the timber is protected by aluminium flashing.
The plant concept was developed by landscape architects Growth Industry and implemented by landscape contractors Blakedown Landscape. The surrounding tall buildings produce shadow and gusting winds, but also raise the temperature. In addition, all materials had to be craned into the garden. However the location also proved an inspiration.
As Katherine Akers Coyle of Growth Industry explains, “the physical nature of the site – narrow, enclosed and dominated by water – inspired the use of plants from similar natural environments.” Growth Industry developed a planting that mimicked the environment of wooded ravines to create a tranquil space for quiet relaxation. The range of specimens includes magnolias, acers and mature tree ferns.