BANNER: Building Greener - A project managed by CIRIA http://www.ciria.com/buildinggreener mailto:buildinggreener@ciria.org
CIRIA logo

home > green walls > benefits

Green walls

Walls occupy a far greater surface area of buildings than roofs. Using plants to green walls introduces colour and variety, and can provide benefits for biodiversity, building thermal efficiency and amelioration of pollutants, all for a small ground level footprint. The creation of foraging and nesting habitats can also complement the use of green roofs and nest boxes.

Biodiversity

In areas of limited potential for traditional forms of greenery the use of green walls can offer an elegant, practical and cost effective solution to help to meet a number of regional and local biodiversity action plan targets. Green walls provide habitat for insects, which in turn will be food for insect-eating birds and bats. They can also provide a transit route for wildlife between habitat at ground level and that established on a green roof.

The choice of plant will affect the species that use it for foraging and/or nesting. For instance the branching structure of ivy provides plenty of places for birds to nest and roost. It is also late flowering and so provides an important seasonal nectar source for birds. A number of BAP species including house sparrow, song thrush and spotted flycatcher are likely to benefit from climbers. The benefits for common species, such as blackbird, robin, mistle thrush and wren should also not be overlooked.

Climate change and mitigation and adaptation

During summer months plants can shade walls from the sun and provide a cooling affect through evapotranspiration. This leads to a reduction in the maximum temperature of the wall, which in turn helps to reduce building solar overheating. This is most effective where plants are used on south facing walls that are in the sun for most of the day, and on west facing walls that experience afternoon heating. Plants can also be used to shade windows, a technique that is called ‘bioshading’.

In the winter, plants can provide insulation by maintaining a layer of still air between the plant and the wall, which reduces convection at the wall surface. The effectiveness of winter insulation provided by climbing plants is related to the thickness and coverage of growth. The reduction in wall wetting, on certain types of wall, can also lessen the amount of cooling through evaporation at the wall’s surface.

Aesthetic and other benefits

The greening of walls can, in a similar way to the planting of trees, do much to improve public enjoyment of the urban environment. Plants can be used to create visually dramatic building vistas or to soften hard surfaces. The use of plants can also help to create locally distinct and identifiable urban areas.

Contrary to received wisdom, climbing plants - if managed correctly - can actually help to protect the surfaces of buildings from damage, defending walls from driving rain/ hail and in some cases reducing the damage caused to cladding systems by ultra-violet light. Climbing plants can also play a role in reducing atmospheric pollution, trapping particulates and concentrating certain pollutants in their tissues.



sitemap