Capitol Plaza Green Roof 2
Capitol Plaza Green Roof 1
Capitol Plaza Green Roof 3

Capitol Plaza Green Roof Addition

Built atop a two-level parking garage, the 11-story office building is approximately 153,344 sf including plazas, while the new green roofs account for 11,000 sf. A structural evaluation was provided including detailed analytical computations to evaluate the roof’s capability of supporting the green roof addition plus required service loading, such as snow load, live load, and snow drifts.  Additionally, certain areas of the main roof and penthouse roof frame were evaluated to receive solar equipment. The roofs were determined to be adequately designed to support the anticipated loads from the green vegetative roofing assembly in addition to the multiple load combination.

A survey was conducted to categorize the scope of work needed for the green roof addition and provide roof plan view drawings for initial cost estimates. Following the survey, plans and specifications were prepared for inclusion in the application package for DDOE’s Green Roof Rebate for Targeted Large Retrofit Program.  The scope also included designing the specified green vegetative roofing system, providing structural waterproofing details to integrate the system application with those of the manufacturer standard details, and preparing selective demolition and removal of the existing roofing assembly to accommodate the new application.

Project Details


Polinger Company



Square Footage


Year Completed