Factors to Consider for a Vegetative Roof

Vegetative roofs can be "too light". Materials used to build highly lightweight systems—16 pounds per square foot or lighter—can potentially be harmful to long-term plant health and viability.

Fremont, CA: The vegetative roofs offer a wide range of advantages and incentives for facility owners and their tenants. These benefits include easily accessible green environments, habitats for birds, butterflies, and insects, and even completely new spaces, such as playgrounds at city schools or childcare facilities. They help to reduce the urban heat effect of the island by giving shade and removing heat from the air through evapotranspiration, which inevitably leads to a cooler air temperature above the roof surface. Green roofs can also act as excellent tools for stormwater management.

These problems are discussed below as general considerations where green roofs are either designed or already built.

Weights

The weight of the vegetative roof will range from 16 to 60 pounds per square foot, depending on the depth of the growth medium, the form of planting and the cumulative weight of other additions, such as pavers or water features. Often ask the manufacturer or contractor to provide you with the full saturated weight of the overall green roof system.