Low Pitch Green Roof

Above 5 degrees roofs are considered to have a pitch which may affect the design.

Low pitch green roof.

Before the plants go up a structural engineer should check to ensure that the roof can support the weight of the engineered growing medium and plants. Moreover low slope metal roofs are not prone to the degradation experienced by organic materials enabling these roofs to better resist the elements. It is the task of the designer to make adjustments in the green roof system accordingly e g. Sloped roofs retain less water in general and the moisture content varies from the ridge to the eave lowest edge of the roof.

Green roofs lower surface temperatures often by 50 degrees fahrenheit or more. Even a flat roof should have some pitch so that it sheds water toward gutters. The most crucial component of any sloped green roof is the confinement system which holds the growth medium in place during the roof s early stages of development. Drainage thickness of growing media plant varieties etc.

In retrofit projects a sub framing system is attached to the existing flat roof surface to provide a minimum 12 roof pitch. If not properly secured a pitched vegetated roof can erode and slip under heavy rain excessive irrigation or poor plant growth.