Schematic Design

There are many options for building a green roof. For a more comprehensive approach to designing green roofs, see LEEDuser’s green roofs strategy page. 

Option 2: Green Roof on 50% of Roof Area

Some municipalities and utility companies offer rebate for projects that install “cool” roofs.

Generally, there is no cost differential between light-colored roofing material and darker roofing materials.

The use of a light-colored roofing material typically reduces cooling bills, especially for low-rise buildings. 

The Lawrence Berkley National Laboratory has a database of typical roofing materials and their

If your roof has multiple pitches and material types, you can use a “weighted- area SRI” value, using "Equation 1" as follows from the LEED Reference Guide. See the Roof Weighted Average Calculator in the Documentation Toolkit for more examples and to see if your roof complies.   

Why are sloped roofs treated differently? A surface absorbs more energy from the sun when it is parallel to the ground plane. In the summer months when the heat island effect is more of a problem, the sun is nearly overhead, and flat roofs are in a position to absorb more heat, so it’s more important for them to have a higher

Sloped roofs have different minimum

The “solar reflectance index” or