Roof and water
Green roof
housing office school bus stop
It is a roof covered with plants over layers of substrate, drainage and waterproofing. It can be light with low plants or deep like a garden.
What it solves
It retains part of the rain and releases it slowly. It cools the roof surface and the nearby air, which in tropical cities lowers the heat reaching the spaces below.
Today
Calculate the load with saturated substrate, use a root-resistant membrane and choose plants that tolerate strong sun and short droughts. Plan for irrigation and maintenance access.
Common mistake
Putting soil on a slab without checking its capacity or drainage, which causes leaks and overloading.
Tomorrow
With native plants and some water, a green roof can host bees, butterflies and birds in the middle of the city. It is best designed with enough substrate so it does not depend on constant irrigation.
Fact An extensive roof has 2 to 12.7 cm of substrate and an intensive one more than 12.8 cm.
Where it comes from
- 1Scandinavian log house Norway and Scandinavia, Viking era to the 18th century
A sod roof over several layers of birch bark, which provided the waterproofing. - 2Traditional Icelandic farm Iceland, living tradition
Sod roofs are still common in traditional rural buildings. - 3Modern green roof Germany, since the 1960s
The current technique was developed there, and today an estimated 10% of German roofs are green. - 4Green bus stops Singapore, 21st century
Green roofs on bus stops lowered air temperature by up to 2 °C.
Masters
- Roberto Burle Marx Gardens of the Ministry of Education and Health, Rio de Janeiro, Brazil
He designs gardens on the building’s terraces with native plants and curving forms meant to be seen from the offices above. The roof becomes a landscape.
Appears in the routes
See also
Also in Roof and water
Diagrams and texts by LDB Arquitectura. They are shared under the CC BY 4.0 license, which allows them to be used and adapted with credit to the source.