Green Roof Studies

Green roofs can be used to provide for rainwater detention or retention, to increase the thermal resistance and capacitance of a building roof, to reduce the urban heat island effect, and/or to provide green space for animals and people on what would otherwise be a hard-surfaced area. Green roofs are of two basic types: extensive and intensive. Extensive green roofs have a relatively shallow soil base, making them lighter, less expensive, and easier to maintain than intensive green roofs. Extensive roofs usually have limited plant diversity, typically consisting of sedum (succulents), grasses, mosses, and herbs. They are often not accessible by building users, but may provide for “natural” views from adjacent rooms or neighboring buildings. Intensive green roofs have a deeper soil base than extensive green roofs.

Several studies were conducted in collaboration architecture firms on projects with green roofs to examine the thermal performance:  a) Roddy/Bale garage and dance studio, built in 2005, Seattle, Washington designed by Miller Hull Partnership. The 1100 ft² (102 m²) roof covers conditioned (dance studio) space and unconditioned (garage) space. A small office, with a conventional roof, overlooks the green roof, which is planted with various sedum species and mosses. b) the Indigo (also known as 12W) by ZGF Architects and Gerding Edlen Developers built in 2009 and the Cyan by THA Architects, GBD Architects and Gerding Edlen Developers also built in 2009 in Portland, Oregon