Green roofs are rooftops equipped to grow gardens. They can grow food, be a place to relax in, help control internal and external temperature, or any combination of these. An additional benefit is boosting the productivity of solar panels during the warmer months of the year.
Green roofs are growing in popularity, both internationally and in Australia. In Germany, gardens cover 15% of all rooftops, with over one billion square metres of green roof, and in France it was recently mandated that all new buildings must be covered with either gardens or solar panels. An inspiring step forward.
In Australia, green roofs are also on the rise. Local Governments in Sydney, Melbourne and Adelaide have created guides and policies to support green infrastructure.
Design considerations for green roofs
Gardens with a wide range of plants species and small to large plant sizes will be naturally resilient and easy to manage. They provide greater insulation for the building and create an environment favourable to supporting wildlife.
Rooftop gardens frequently suffer more extreme weather conditions (particularly stronger winds) than those at ground level. Appropriate plant choice is essential. Green roof systems are designed to take into consideration the loading capacity of the existing or proposed roof, access to the roof, maintenance requirements, wind and light conditions, drainage and the best plants and growing media for the desired purpose. As we become more urbanised, it is important that we use our spaces and resources wisely. The backyard may be shrinking, but there are opportunities right above us.
This is an edited version of a larger document from ‘Do it on the Roof’. For more details on Roof Gardens in Melbourne, their web site: www.doitontheroof.com is a good jumping off point.