The design team developed an 11-level facility in which only the top two levels are above grade; the remaining nine levels are built into and extend out of the landscape, cascading down the hill. Despite its massive scale, the use of glass to provide natural light and eight planted interconnected courtyards unite this very site-specific building. Each greenroof and courtyard is both a literal and abstract expression of five local eco-regions, from the Piedmont uplands down to the coastal plain encompassing 200,000 plants, more than 300 native trees, and about 100 varieties of Sedum. Due to the variety of plants ranging from shrubs to grasses to Sedum mats from Sempergreen, there are four different soil blends on the project from rooflite.
Year: 2013
Owner: General Services Administration (GSA)
Location: Washington, DC, USA
Building Type: Municipal/Government
Type: Extensive & Intensive
System: Custom
Size: 550,000 sq.ft.
Grade: 2%
Access: Inaccessible, By Appointment
Designers/Manufacturers of Record:
General Contractor: Clark Construction Group, LLC
WDG Architecture: A/E Headquarters Building
A/E Support Buildings / Garages: McKissack and McKissack
Greenroof and Interior Design: HOK, Inc.
Historic Preservation Architect: Quinn Evans I Architects
Structural Engineer: Cagley & Associates
Greenroof System: Vegetative Roof Assemblies®, Henry Company
Roofing Contractor: Gordon Contracting
Growing Media Consultant: Roofmeadow®
Plant Consultant: Ed Snodgrass, Emory Knoll Farms
Pre-vegetated Sedum Mats: Sempergreen
Landscape Architecture, Environmental Science and Sustainability Consultant: JJR
Growing Media: rooflite®
Architect: Perkins + Will
Courtyard & Landscape Installation: ValleyCrest
Greenroof Plant Supplier & Vegetation Installation: Tilson Group
Landscape Architect: Andropogon
