A 2006 study by the university of michigan comparing costs of conventional and green roofs showed that on average installing a green roof costs about 22 00 sq.
Intensive vs extensive green roof system.
For a conventional roof.
Extensive green roof systems extensive systems are simpler and lighter weight than intensive systems.
Semi intensive roofs are generally used within highly visible area s to improve aesthetic design using small shrubs forbs and grasses.
Our semi intensive green roof systems include a richer deeper substrate and drainage solution compared to extensive roofs enabling use of a wider range of complex plant mixtures.
15 to 50 per square foot.
Green roofs can help reduce energy costs for a building by acting as another layer of insulation between the inside and outside of the roof.
Due to their light weight and low profile they require less structural support and can be used on roofs with a slope of 30 b0 and higher.
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.
There are no specific requirements for a green roof insulation layer in a simple extensive green roof.
These systems are ideal for efficient stormwater.
A semi intensive green roof can give rise to a richer ecology with more diverse plant and animal species.
It also allows for a formal garden to be installed with paths grass lawn and flowers or pot plants.
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 the growing medium depth for an extensive green roof system is typically 6 inches or less.
Typically these roofs will have more soil and some small shrubs as well as the low growing wildflowers and sedums found on an extensive roof.
Green roof insulation becomes more of a factor on new build commercial projects with intensive roof systems.
These systems range in thickness from 2 6 94 and weigh approximately 15 30lbs per sq ft.
Intensive green roofs can support the growth of a wide range of plants including shrubs and small trees while the extensive green roofs can typically only accommodate a small selection of drought tolerant plants with shallow root systems.
8 to 20 per square foot.