Multistorey car parks seldom hit the headlines, but the one at National Grid’s HQ in Warwick has made news far and wide, even on the Australian Broadcasting Corporation.
The reason is because it features one of Europe’s largest living walls. "If you’re going to have a green wall you might as well make it the biggest one," says Simon Carter, head of corporate property at National Grid. The car park’s expanse of lush greenery is certainly a contender for that title, extending across an area of more than 1,000sq m.
Living walls have come a long way since French botanist Patrick Blanc’s "vertical garden" was unveiled on London’s Athenaeum Hotel in 2009. Now they can be found on hotels, business headquarters, major public buildings and infrastructure projects as well as some homes.
"It’s because of the increasing awareness among clients and the general public of sustainability," is how Chris Medland, director of One-World Design Architects, designer of the National Grid project, explains the trend.
The decision to make such a significant green statement on a humble car park grew out of a meeting. "We were discussing the issue of the long views from Warwick Castle to the site and considering several different screening options to conceal the car park," says Medland.
"A living wall was one of the options under consideration. Then National Grid said we should go for it, and make it big. As a practice our focus is sustainability, so we saw it as a great opportunity."
The 446-space split-level car park has a steel-framed structure largely obscured by the 97,000 plants of the living wall. As a building that is generally functional in appearance and traditionally intended to house distinctly un-environmentally friendly vehicles, the multistorey car park is ripe for a green makeover.
"Any opportunity to add sustainability and biodiversity should be taken, but every car park should be incorporating this to offset carbon," argues Medland. There is also a practical benefit: "A car park is a very simple building so in that sense it is ideal for a green wall."
For National Grid the living wall is a long-term commitment that will require ongoing maintenance. But it also offers significant environmental benefits — attracting wildlife, absorbing carbon dioxide and filtering rainwater — and is a vital element of the scheme’s overall sustainability, alongside features including bird and insect boxes as well as ground-level porous paving.
More than 25 different plant species are anchored in soil within the wall panels, with the species choice providing year-round variety and colour. A spokesperson at living wall specialist ANS Global explains: "The plant species have been selected to include predominantly native and wildlife-friendly species, the majority of which are evergreen to provide coverage all year round".
What the planting includes
• Mentha, which acts as a deterrent to wasps.
• Plant species that are intended to attract butterflies, such as Hebe pinguifolia ‘Pagei’.
• Others that provide nectar for bees, such as Vinca minor ‘Bowles’s Purple’.
• Plant species that have good nesting properties and provide protection for birds in winter and early spring, such as Buxus sempervirens.
• Fruit-bearing plants, such as strawberries.
Key outcomes to date
• The living wall won overall winner in the Warwick in Bloom Awards and also won in the commercial premises category.
• The sustainable feature contributes to National Grid’s overall corporate social responsibility.
• National Grid’s Simon Carter says: "Feedback from staff and local community leaders has all been positive."
• A living wall calls for long-term commitment from the client. One-World Design’s Medland says: "National Grid deserves praise for doing this. It takes dedication to take on the maintenance for 25 to 30 years."
• Medland points out: "There were many lessons in making this work technically — things like how to get the irrigation right. You have to ensure you don’t have water dripping onto cars."
• An expert project team was valuable to the delivery of this project, which was One-World Design’s first living wall scheme.
|Architect||One-World Design Architects|
|Living wall||ANS Global|
|Lead consultant, structural and mechanical and electrical
|Design and build contractor||Goldbeck|
|Project and cost consultancy||Deloitte|