What is a ‘Green Roof’?

Green roofs have come a long way since I started building them 5 years ago in Australia. Thankfully now the use of green walls and green roofs is becoming not only more common, but extremely desirable across the built environment.

Also known as ‘living roofs’, green roofs serve several purposes for a building, such as absorbing rainwater, providing insulation, creating a habitat for wildlife, and helping to lower urban air temperatures and combat the heat island effect. There are two types of green roofs: intensive roofs, which are thicker and can support a wider variety of plants but are heavier and require more maintenance, and extensive roofs, which are covered in a light layer of vegetation and are lighter than an intensive green roof.

What are the benefits?

• Use the roof to grow fruit, vegetables and flowers
• Reduce heating and cooling loads on a building
• Increase the lifespan of a roof
• Reduce storm-water runoff
• Filter pollutants and CO2 out of the air
• Filter pollutants and heavy metals out of rainwater
• Easy to retrofit your existing roof or create a new one in less then a day
• Can be flat or inclined and combined with other types of roofs

Check out this informative paper by German earth building expert Gernot Minke on his research into the practical uses of Green Roofs.

Inclined green roofs – Gernot Minke

For your amusement – a friend of mine had the great idea to use guinea pigs at his farm in Brazil to keep the turf down on his green roof – it worked a little too well! The guinea pigs loved it.