Green roofs have featured on Grand Designs and other Eco Home programmes but I have always been intrigued as to how green roofs works. In the UK green roofs are all the rage but what are the advantages of green roofs?
What are green roofs?
Green roofs are vegetated layers that sit on top of the conventional roof surfaces of a building. Green roofs are partially or completely covered with vegetation and soil, or a growing medium, planted over a waterproofing membrane. Green roofs may also include additional layers such as a root barrier or drainage and irrigation systems.
Green roofs can also describe a roof using some form of “green” technology, such as solar panels or a photovoltaic module.
Green roofs environmental benefits
Green roofs can be advantageous for many reasons:
- Reduce heating and cooling
- Increase the roof life span by at least double
- Grow fruits, vegetables, and flowers
- Reduce run-off storm water
- Filter pollutants and CO2 out of the air
- Insulate for sound and heat
- Filter pollutants and heavy metals out of rainwater
- Increase wildlife habitat
How do I get a green roof?
If you wish to install a green roof, contact your local planning department and explain what you are aiming to do, especially if it is on a permanent structure such as an office, dwelling or garage. They will then advice on what your next steps should be, they will also advise you to speak to Building Control who will be interested in the technical details of your green roof installation. Building Control will also advise if you need to get a Structural Engineer involved.
Green Roofs in Europe
Germany, Austria and Switzerland are currently the leaders as far as green roof systems go. In particular, in Germany it’s a legal requirement in many of their large cities to include green roofs on new flat-roofed buildings. On top of the regulations there are grants, administered by local authorities that can cover up to 50% of the additional cost of installing green roofs.
Green roof legislation was the main reason for the widespread introduction of green roofs in these countries. The loss of green open space at ground level is now compensated by installation of the green roof systems. One of the many advantages for them of green roofs is that they make up part of the integrated Sustainable Urban Drainage Schemes to minimise the amount of storm-water run-off, reducing the risk of urban flooding after heavy rain.
Green roofs initiatives within these countries have a high international profile and share one feature in common: although they may be supported by national government policy and strategy, they operate at the regional and city level, and focus on the particular needs of that region. They are also all characterised by a high degree of interaction and partnership between local authorities and city governments, local research communities, the green roof industry, and community and regeneration organisations, again delivering solutions to meet regional needs.
Green Roofs in the UK
To date, there is no example in the UK of such a coherent and integrated regional initiative to bring forward green roof infrastructure and associated sustainable building techniques. However the University of Sheffield is leading extensive research in green roofs and has impressive plans for green roof development in Sheffield.
Sheffield University are striving to establish green roof sites in the sub region, in order to demonstrate their benefits to mainstream developers. A significant number of demonstration green roofs in the South East and London (over 60) have proved vital in gaining confidence in green roofs with private developers.
As a result, this area has revolutionised green roofs implementation - now we just need to get behind projects like this one in the UK so that we can keep up with our eco-friendly European friends.
So if you thought green roofs were just for eco-geeks then think again.