Green Roof Infiltration

Integrating a green roof into a historic building rehabilitation project may appear to be an easy solution to reducing the urban heat island effect improving storm water management and improving the energy efficiency and sustainability of the building.

Green roof infiltration.

Use practices that do not require infiltration. The minimum thickness of the green roof growing medium must be calculated as follows where the impervious roof area to green roof area ratio is less. Green roofs can help reduce energy costsfor a building by acting as another layer of insulation between the inside and outside of the roof. Rainwater harvesting green roofs vegetated swales and.

A green roof will typically intercept the first 5mm and more of rainfall providing interception storage. Green roofs are unique in that they have the ability to capture and retain a volume depth of rain from each rainstorm. This captured water is then evapotranspired back to the atmosphere through the green roof vegetation. Impervious roof areas that direct runoff onto the green roof cannot exceed 50 of the green roof area which is equivalent to a maximum hydraulic impervious runoff loading ratio of 0 5 1.

This is most noticeable in intensive green roofs since there is a thicker and more consistent layer of soil which provides a higher insulating value.