- News
- Magazine
- Awards
- CRC
- Legislation
- Housing
- Renewables
- Non-domestic
- Water
- Energy
- Waste & recyc..
- Refurbishment
- Innovation
- Materials
- Biodiversity
- Interiors
- Books
- Training
- Transport
- Links
- Events
A modular green roof
http://www.greenbuildnews.co.uk/images/img/articles/297_198/Articles_133_1_1269610410.jpg
Green roofing can help to insulate a building
http://www.greenbuildnews.co.uk/images/img/articles/297_198/Articles_133_2_1269610410.jpg
If the green roof was once the domain only of environmental pioneers, it has now become a fact of mainstream construction. Long gone are the days when it was enough for a roof to waterproof a building, with added value because it provided effective insulation or contributed to the impact of a new design. Today a roof has to work much harder – and keep on working harder for decades.
There is a whole host of reasons for this, including:
- exponential population growth (with most pressure on the core of densely populated urban areas);
- depletion of financial and energy resources;
- threats to the environment;
- legislative changes
It’s no accident that the roof is often referred to as the fifth elevation – a reflection of the growing expectation that they should also perform aesthetically. Indeed, roofs must also start to perform as an amenity if we are to halt the spread of urban sprawl. With more pressure on garden space, take the garden to the roof. A roof garden can even provide a source of home-grown vegetables.
Growing population
The number of households in Britain increased by 7.8 million between 1961 and 2004, and the population is expected to reach 70 million by 2029. Add to this the United Nations’ findings that half of the world’s population lives in cities and it’s logical that roofs must do their part help to ease some of the pressures on space, environment and quality of life.
Indeed, there are all kinds of growing demands on the roofs we design today: thermal performance, carbon footprints and whole life costings are all major considerations. Roofs must help to increase biodiversity, conserve – and even generate – energy, and serve as much-needed public amenities.
Pivotal role
Green roofs are the perfect example of getting a roof to work harder. Planted roofs can play a pivotal insulating role. Research by Nottingham Trent University found that the temperature beneath the membrane of a conventional roof fluctuated between 0.2 and 32ºC – while in contrast temperatures beneath a green roof varied much less, from 4.7 to 17.1ºC.
Heat lost from a poorly insulated roof is a bigger problem than through poorly insulated walls and new legislation reflects this. The new Part L of the Building Regulations is expected to demand a 25% cut in CO2 emissions compared with 2006 – a key step in the drive for zero carbon newbuild by 2019 (with domestic buildings due to comply three years earlier).
Flora and fauna
Green roofs, when efficiently waterproofed and insulated, can make a significant contribution to biodiversity, providing habitats for a wide range of flora, fauna, birds and invertebrates. Benefit can be gained in reducing the urban heat island effect, which makes cities hotter than the countryside that surrounds them. Buildings designed with green walls as well as green roofs can make the greatest contribution to this.
Additional benefits
The green roof can also have an effective part to play in sustainable urban drainage schemes. Typically, a green roof will intercept the first 5mm of rain, making a significant dent in the levels of water run-off hitting a town or city’s drainage system in today’s erratic weather patterns. There is convincing evidence that a green roof can reduce the impact of external noise on the interior of a building – and deeper substrates can lead to significant reduction in the noise entering a building. Energy capture adds another dimension to the manner in which a roof can contribute more to a building’s performance, by using photovoltaics to generate electricity.
Mike Crook is trading director of SIG Design & Technology, suppliers of the eco-friendly single ply membrane Rhepanol made from polyisobutylene (PIB). The company offers a single source for a range of complementary roofing products, with an insurance-backed warranty to cover whole roof packages. For further information visit www.sigrdandt.co.uk .
Search related articles
