WTCW – Roof Replacement

Our building envelope team has made sustainable design a priority, and this green roof project is a testament to that! The World Trade Center – West building in downtown Seattle, is the location of the first green roof at the Port of Seattle.

The initial design intent was to provide a roof overlay with a single ply membrane; however, it became clear that this roof would be an ideal location for a green roof system.  This system comprises a single ply membrane overlay, growing medium in a tray system and flowering sedums along with rock ballast pathways.

The main aspects of the design include creating a place of respite for pollinators; sequestration of  carbon and mitigation of run-off into Elliot Bay. Other environmental benefits include, lowering of surrounding air temperatures by evapotranspiration and reduction of the heat island effect. Apart from the technical implications, the green roof provides an increase in the general aesthetic of the built environment, especially where higher offices look down upon the roof surface.