Green Roofs

Soprema, Inc recently visited our office to present green roof systems to SBLM.

Green roofs are an excellent way to contribute to environmental sustainability while, in some cases, taking advantage of typically unused space as an amenity.

There are two types of green roofs, extensive and intensive, each with their own design considerations and benefits. 

Extensive green roofs are of shallow depths and typically consist of hardy planting medium, such as sedum, which require little maintenance and lower excess structural load capacity. Due to its shallow nature, extensive systems are not typically used as an amenity. Conversely, intensive green roofs include much deeper soils which can support grasses, shrubs, trees and, and subsequently, people.  Intensive systems have a higher demand for maintenance and structural load capacity.

            

Regardless of the type of green roof, the environmental benefits are evident in the areas of stormwater management, heat island reduction and air filtration. Stormwater runoff is managed by retaining precipitation in the growing medium. This reduces the volume and runoff flow into the stormwater sewer systems, consequently relieving the system of potential overflow. Green roofs have also demonstrated effectiveness for reducing the urban heat island effect. Solar energy is absorbed by the vegetation and through evapotranspiration the surrounding air is cooled. In addition to reducing the heat island effect, the plant covers can also filter atmospheric pollutants.

Often lost in the environmental benefits are those related to the structure for which it sits. While the positive impact to the outdoors is very evident, green roofs are also integral as a sustainable building construction component. The thermal insulation properties of a green roof can regulate temperatures in the building, resulting in lower HVAC demands and helping save energy. When designed, installed and maintained properly, the green roof also protects the building’s roofing membrane from UV rays which can extend its useful service life. 

While green roofs have sprouted in more urban areas where stormwater demands and heat islands are a common problem, they have also advanced thanks to the interest of building owners.  In addition to the transformation of dead space to roof gardens and the cost benefits of reducing the heating load on the building, owners are also realizing the advantages of incentive based zoning and improved marketability.

Our thanks to Soprema, Inc for upping our knowledge base with an enjoyable presentation on green roofs.

- T. Lopes