Evergreen State College is located in Olympia, Washington and is committed to sustainable development. It's new building is being evaluated for Gold Status under the USGBC's LEED program and features an impressive 24,000 square foot green roof built on 13 separate green roof areas. It was designed to encourage student interaction and be a visual representation of the sustainable approach to designing and building the entire facility.

The cost of roughly $18 per square foot also includes polyisocyanurate insulation with an R-value of 21; multi-ply modified bitumen roof system which incorporates recycled materials and stainless steel flashings.

The growing medium was Garland's Oasis media mixture, a very lightweight mix specifically designed by Dr. John White of Penn State University for green roof applications and the depth varied from 4" to 6". The plants were primarily low growing ground cover such as sedums and various perrineal flowering species with a total of thirty-three species used.

Garland's Filterdrain 110 was used as the drainage layer. This is a high density polyethlene filter fabric fused to a geotextile filter fabric. The irrigation system was a below grade drip irrigation system, that will only be used during severe drought periods.

The waterproof membrane is Garland's multi-ply SBS polymer modified bitumen roof system that includes post-consumer recyled tires and glass and post-industrial boiler slag. This project also included some areas with an Energy Star approved white coating where a green roof was not feasible. The combined benefits of the reduced roof top temperature and the high r-value insulation provides the owner with a very energy efficient roof system. These benefits help reduce the energy needs of the building which was designed with no cooling system. The windows are operational and provide necessary cooling.

Roofs age primarily from heat, Ultra-Violet radiation and physical abuse. The green roof will protect the roof system from these harmful elements and therefore, it is anticipated that the life of this roof will significantly exceed 30 years. Another important benefit of installing the green roof was the significant reduction in size of stormwater retention ponds that were needed for this project. All rainwater that filters through the green roof system will overflow into a 20,000 gallon resevoir tank designed to slowly release water back to the environment.

This green roof project was designed to integrate with the operation of the building and its occupants and reflect the mission and values of the univeristy. The students walk past these roofs every day and use benches and patio areas around many of these green roofs that provide places for the students and staff to interact.