With that in mind the real variable in the weight is the depth of planting material.
Intensive roof design.
Vegetative roofs are divided into two categories.
An intensive green roof weight varies from 35 to beyond 100 pounds per square foot when dry.
Rooftop garden or intensive vegetative green roofs are typically designed as usable spaces made up of lawn perennials bushes and trees.
Plant selection and design greatly affects the maintenance required for the upkeep of these roofs.
Intensive green roofs require the deepest soil and have the greatest impact on the structural design but they also accommodate all types of plantings including large shrubs and trees.
Intensive green roofs offer a great potential for design and biodiversity.
An intensive green roof often contains more soil for the production of large roots a wider root barrier and more.
Once the plants are installed and the soil is moist these rooftop green spaces can weigh as much as 150 pounds per square foot.
This style of green roof is capable of supporting 82 150 pounds of vegetation per square foot.
The variety of plants possible is numerous including sod grass lawns perennial and annual flowers shrubs and even small trees.
Intensive roofs are accessible and often include areas of hardscape structures and other features that create beautiful gardens on the roof.
Intensive style green roofs are the most detailed and strongest of them all.
The roof drain must allow for sub surface drainage while providing aesthetically pleasing grates and domes.
Extensive green roof an extensive green roof system is characterized of its vegetation ranging from sedums to small grasses herbs and flowering herbaceous plants which need little maintenance and no permanent irrigation system.
Intensive roof design intensive roof construction requires roof drains that will allow sufficient drainage yet protect the integrity of the growth media and vegetation.
Greengrid 6 inch or 8 inch option.
Intensive systems allow the designer to create a park like setting so they are the best option for roof gardens that will be occupied.
A typical growing medium depth of an intensive green roof is 6 inches or more.
The growing medium depth for an extensive green roof system is typically 6 inches or less.
The planting medium in intensive green roofs starts at 6 inches although you will see some wiggle room in various definitions and really elaborate designs may exceed a couple feed.
Intensive designs usually consist of a mixture of hard and soft landscaping and incorporate plants that require regular maintenance such as watering fertilizing and mowing.