There are a number of social, economic and environmental benefits to green roofs, including:
- Increasing home energy efficiency - cooling in summer, insulation in winter.
- Filtering and cleaning toxins from both air and water.
- Reducing Carbon Dioxide Emissions.
- Retaining rainwater before it evaporates, reducing the likelihood of flooding.
- Reducing urban temperatures and associated smog.
- Insulating against sound and noise.
- Preserving and enhancing biodiversity.
- Providing aesthetic appeal and 'green space' recreational opportunities.
- Using recycled materials like aggregates and plastic sheets.
There are two types of green roofing:
- Intensive Living Roofs - These incorporate plants from between 1 to 15 feet high, including shrubs and trees. They require deep levels of soil to support them and a weight-loading roof. They support a high level of plant and wildlife diversity but require ongoing maintenance and extensive irrigation. They are not suitable for most domestic Buildings.
- Extensive Living Roofs - These incorporate low lying plants from 2 to 6 inches high. They require only a few inches of soil to support them, and only need a low weight-loading roof. They are low maintenance and can be used for any kind of roof, including sheds or garages, houses,balconies extensions and commercial buildings.
How to construct a green roof:
A green roof system consists of layers that mimic natural processes and also protect the building and roof. The basic components are; a waterproof layer, root repellent membrane, filter cloth to allow water to drain but prevent soil escaping. Moisture blanket (to ensure enough water retention for plant life), drainage system (to drain excess water) Soil Substrate, seeds and plants. The soil is the growing medium and should be lightweight and free draining, but also be able to hold enough moisture for the plants to survive. Recycled aggregates such as crushed porous brick are often used in the soil substrate, with the added benefit of increasing its sustainability index.
Visit www.sustainablebuild.co.uk for a deeper understanding of how you can set up and manage this system with your own home.