Low Pitch Green Roof

Even a flat roof should have some pitch so that it sheds water toward gutters.

Low pitch green roof.

Drainage thickness of growing media plant varieties etc. If not properly secured a pitched vegetated roof can erode and slip under heavy rain excessive irrigation or poor plant growth. 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. 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. For a green roof installation that pitch should be at least inch per foot of run. Above 5 degrees roofs are considered to have a pitch which may affect the design. Moreover low slope metal roofs are not prone to the degradation experienced by organic materials enabling these roofs to better resist the elements.

Most vegetation will grow on quite sever slopes but the designer must consider the practicalities of installing the green roof and just as importantly how the roof is to be maintained. In retrofit projects a sub framing system is attached to the existing flat roof surface to provide a minimum 12 roof pitch.