The 10 Benefits of Building a Green Roof
More and more buildings in Australia are now being constructed with plant-covered roofs, also known as 'living roofs'. They’re not just an architectural trend, they serve a far greater purpose. These green roofs have existed for thousands of years in Scandinavian countries, where they used layers of turf, or "sod", for insulation and a wood alternative.
It might not be new, but the trend of green roofs is growing all over the world. So, why would you choose a green roof?
The answers may range from simply aesthetic reasons, building an eco-friendly home, increasing biodiversity, creating a pleasant outdoor space, or it may also be because green roofs comply with stormwater regulations. Whatever the reason, Southeast Queensland would greatly benefit from greener roofs.
The Green Roof Revolution in Australia
Although Australia is lagging in green roof utilisation, it’s not far off from the rest of the world. In Europe, many cities have required modern buildings to use green roofs - it’s common is the Austrian city of Linz. In the United States, Denver and San Francisco are leading the charge towards greener roofs. In 2009, the central business district of Toronto in Canada also adopted a green roof policy in half of the city’s building.
The green roof revolution has certainly reached Australia with the construction industry developing more eco-friendly designs. Infrastructure Australia has recognised the benefits of green roofs. The organisation has recommended to the Australian government to improve green infrastructure through better taxation, planning incentives and policy reforms.
The NSW government has made a Greener Places draft policy to push the use of green roofs as not only an asset to building environments, but also an essential design for healthy urban communities. The city councils of Sydney and Melbourne have reinforced and nurtured the idea of green roofs for years.
10 Benefits of Green Roofs
- Increases lifespan of a roof. A green roof that is properly installed and maintained can prolong the life of a roof 2 to 3 times as long. It may last between 30 to 50 years.
- Decreases ambient temperature. Green roofs may reduce the fluctuations in temperature of roof surfaces. This results in cooler temperatures in buildings and lowered air-conditioning costs.
- Serves as rainwater buffer. A green roof effectively absorbs rain water and buffers them in the plants and soil. This slows down rain water draining into the sewage system while also purifying it at the same time. Overall, this helps maintain normal groundwater levels and decreases flooding risks.
- Absorbs noise. Unlike hard surfaces which reflects sound, green roofs serve as sound insulation.
- Purifies the air. Like all plants, green roofs filter the air and convert CO2 into oxygen.
- Improves solar panel efficiency. Green roofs are cooler, and this increases the efficiency of solar panels, reducing energy costs.
- Protects against fire. Plants absorb moisture and this creates a natural fire-resistant layer.
- Helps biodiversity and wildlife. Green roofs make a good habitat for bees, butterflies and birds, even in urban environments.
- Improves amenities. For city dwellers, a green roof can provide a great outdoor space when land is limited.
- Reduces greenhouse emissions. A green roof reduces cooling loads, which in turn decreases greenhouse emissions from fuel combustions.
Economic Advantages of Using Green Roofs in Australia
Green roof installation has higher upfront costs, however they have a wide range of ongoing economic benefits. Green roofs increase R-value (the measure of resistance to heat flow through a given thickness of material); decrease HVAC (heating, ventilation, and air conditioning) loads; and, reduce total energy costs.
A green roof also increases property value and marketability, especially in urban areas. Although green roofs are an asset to to any city, economic benefits also depend on design, geographic location, environment types and the infrastructure itself.