How to build a Green Roof

green roof

The design of a green roof depends on client requirements, both in terms of cost and  aesthetics, but also climate  and weather-related.

In Santiago de  Chile, Sika builds for a Mediterranean climate in which most rainfall occurs in the winter months followed by  very dry season. “The actual building process is a team effort that closely involves the customer” says Juan Francisco Jimenez, General Manager,  Sika Chile.

Typically the process has these basic steps:

  • Evaluation of the supporting structure.
  • Waterproofing with the most efficient system for the climate,
  • Thermal insulation if necessary
  • Plant selection by a specialist with consideration of maintenance requirements.

A semi-extensive green roof would typically have cultivation depths of about six inches with different kinds of plants including flowers, ground-creeping plants and shrubs, which would cost a client on average about $75 per square meter.

A layer of insulation, a separation layer, waterproofing membrane, such as Sarnafil F610-12, a drainage composite, such as Sika Drenaje 32, growth medium and vegetable would follow.

Extensive green roofs have a narrower range of herbs, grasses, mosses and drought-tolerant succulents such as sedum, which are known for their tolerance for extreme conditions.

“Chile’s varied geography and climate zones (warm in the north, temperate/moderate in central and cold in the south region) strongly influence green roof design” says Jimenez. “Our task is to provide architects with the technical assitance they need to work in different climates and find new ways to enhance and oxygenate our cites”.