Green Roofs (Vegetated Roof Covers)

Design Considerations for Proposal Review | Green Roofs on Commercial Sites | Green roofs in Connecticut

Green roofs have been in use for many years in Europe. Traditional green roofs, so called intensive green roofs, were composed of a thick sod layer, plants and trees, and required extra structural support. These systems will not be discussed here. An alternative green roof, called an extensive green roof, is gaining popularity in the United States. The extensive green roof uses a thinner, lighter, growing medium, and is planted with low growing, drought tolerant plant species such as Sedum. In most cases, the extensive roofs do not require extensive structural support, yet still provide a stormwater benefit. Research is shows that around 62% of rainfall can be retained by an extensive green roof. There are additional benefits including increased insulation capabilities, which result in lower heating/cooling costs, and reduced heat island effects. In addition, an attractive, functional space can be created in locations where space is often at a premium. More information about green roofs can be found at www.greenroofs.com.

See the list of local vendors for green roof products.

Benefits of green roofs:

About 62% of annual rainfall can be retained by the roof, greatly reducing stormwater runoff volumes.

Decreased need for other stormwater management practices.

Visible green roofs provide a more useful, aesthetically pleasing landscape.

Decreased heating and cooling costs.

Increased life span of the conventional roof because of decreased exposure to temperature fluctuations and UV rays.

For more information, visit the following sections of the CT Stormwater Quality Manual:

Chapter 4, Section 4.4.5

Design Considerations for Proposal Review

Although extensive green roofs do not require the extra structural support that intensive roofs require, the site or building still needs to be analyzed by an engineer to determine weight limits and other site restrictions. Detailed design guidance is beyond the scope of this website, and should be provided by the green roof supplier and an engineering firm.

Green Roofs on Commercial Sites

Green roofs are highly applicable to large commercial settings, and could potentially reduce heating/cooling costs and retain stormwater, thus reducing the need for downstream detention. The City of Chicago has an agressive green roof campaign for commercial and office buildings. Go to this link to learn more about their program: http://www.artic.edu/webspaces/greeninitiatives/greenroofs/main.htm.

Local Examples

Are you looking for more local examples of green roofs? Visit CT NEMO's LID database for Connecticut. This site contains searchable database for LID practices, engineering firms familiar with LID, and construction companies who have installed LID practices.

© University of Connecticut | Disclaimers and Copyright Statements
NEMO is a program of the Center for Land Use Education and Research (CLEAR).
Land, Sea and Space Grant collaborating.