Evidence type: Research
Author(s): Richardson, D. & Jones, G.
This is one in a series of reports produced between 2007 and 2009 within the Natural Economy Northwest (NENW) Programme. The main focus is to
deliver priority action 113 in the Regional Economic Strategy, to optimise the natural environment's contribution to the regional economy and quality of life.
This report considers the potential for green roof development in Greater Manchester and assesses the benefits that green roof development may deliver, particularly in terms of contributing to biodiversity enhancement, the local economy and quality of life.
The principle benefits are considered to be:
- Enhancing biodiversity by providing new habitats in current areas of biodiversity deficiency
- Improving sustainable water management by decreasing storm water runoff, enhancing water holding capacity and enhancing evapotranspiration
- Enhancing energy efficiency by stabalising temperatures at roof surfaces and contributing to insulation
- Enhancing image, particularly in urban cores and urban regeneration areas
- Enhancing amenity value and social cohesion by providing new public spaces in areas otherwise deficient in such areas
- Enhancing roof life
- Directly and indirectly contributing to the local economy
- To overcome the capital and revenue cost constraints the whole life costs of the green roof should be stressed; green roofs can deliver costs savings in terms of energy efficiency, sustainable water management and extended roof life. In addition the business value of a green roof in PR terms could be very significant. The fact that green roofs can increase the roof life of conventional roofing materials is also important to stress.
- To overcome constraints concerning appearance and performance the importance of good design should be stressed. Realistic expectations must be set an early stage of development.
- It is also recommended that proper standards governing green roof construction are developed in the UK, and definitions of green roof typologies be adopted as formal standards.
However it is not recommended that a specific policy requiring green roof provision is implemented at this time. This is because it is considered that a specific policy requiring green roof provision on new and existing buildings would be difficult to properly implement in the absence of an accepted definition of what actually comprises a green roof, and in the absence of adopted building standards for green roofs.
- Green roofs can compensate for green space lost at ground level, and therefore can be seen as contributing to green infrastructure.
- If green spaces are to be provided in the city centre it makes economic sense to provide them on the roofs of buildings.
It is difficult to think of another element of building design that could fulfill all of the potential benefits that green roofs can offer. Where is the aesthetic or amenity value of a conventional layer of insulation? What contribution does a large water storage tank make to biodiversity or to the 'liveability' of a city? Green roofs can make a contribution to the solution of many of the problems posed when trying to develop a sustainable building, or even a sustainable city, and have significant commercial benefit; the case for green roof construction is strong.
Natural England, NWDA, Sita Trust