The benefits of green walls

Why plant or protect green walls? What’s the point of them?

There have been good studies on this, focused on green walls for buildings. These have put pound (or dollar) signs on costs of establishment and maintenance, and benefits including:

  • increased property value (akin to planting street trees)
  • insulating buildings to reduce air conditioning costs in hot climates
  • acoustic benefit where the covering is thick
  • improving biodiversity
  • improving air quality by trapping dust particles
  • reducing the frequency of building facade maintenance
  • air temperature reduction (urban ‘heat island’)

This study concluded that ‘direct green facades’ – ie climbing plants established onto a building surface – are the most sustainable green wall type, and have a very positive net present value.

Westergate Business Park

There are lots of places in Brighton where this applies – around New England for example, Westergate, American Express, and so on.

For Madeira Drive, our most famous green wall, things are a little different. However, the benefits include:

  • green space for relaxation in a community where the vast majority have no garden, balcony or other outside space
  • a habitat for wildlife – 100 species of plants, birds, butterflies
  • a national arboretum for Japanese spindle, and place to learn how to prune, coppice and manage it
  • a place to study Victorian environmental engineering
  • a green lung in an otherwise sparsely vegetated area – trapping dust
  • a more attractive covering for a rendered cliff face that is so much better visually than sprayed concrete
  • a protective coating for the cliff face – limiting damage and deterioration from wind, rain and cold.
  • a place for volunteers to get active and health
  • a backdrop for TV, film, photo shoots and show piece for Brighton & Hove.

It would be useful to do some economics on this – anyone out there with the requisite skills?

Huge potential for green roofs to improve the centre of Brighton

The first feasibility study and audit of the potential for green roofs in Brighton has been published.

green roof

Green roof on the Velo cafe, The Level, Brighton – image by Building Green

The study examined a study area in Central Brighton, to assess the potential benefits of establishing green roofs.

It finds that 61 hectares of roofs in Central Brighton are suitable for retrofitting with green roofs, in a way which brings nature, summer cooling and storm water management benefits and improves the attractiveness of the cityscape.

This is equivalent to 87 football pitches-worth of new green roof space in the 9km2 area of the city that runs between the West pier and Dyke Road, and from Bear Road to Kemptown.

This area is highly urbanised, is susceptible to surface water flooding, and has limited open green space.

More on the benefits:

  • In terms of urban drainage benefits, it is estimated that 61ha of ‘biodiverse’ green roofs could attenuate between 3507.5m³ and 244,000m3 of storm water. In other words, up to 100 Olympic swimming pools of water would be held back from the city’s roads and drains at peak times. This could have a significant combined effect in reducing flooding and the need for additional, costly, engineering infrastructure.
  • Approximately 2.3MWh of electricity could be saved every year on cooling costs for buildings – via reduced or avoided air conditioning.
  • Greening roofs would also reduce the Urban Heat Island Effect, potentially providing an additional saving in cooling costs in the region of 1.3million kWh per annum.
  • The centre of Brighton would be far more attractive at roof level.

This work should be of interest to planners, architects, developers, environmentalists, householders and city businesses.

Download the Brighton Green Roof Audit

The study was prepared by Ben Kimpton (Senior Ecologist – The Ecology Consultancy) and The Green Roof Consultancy, it was supported by Matthew Thomas (former Ecologist – Brighton & Hove City Council), James Farrell (Chair – Brighton and Hove Building Green), Dusty Gedge (Founder – Livingroofs.org and Director – The Green Roof Consultancy) and Lee Evans (Director – Organic Roofs).