24/7 Customer Service 301-315-6260

George Mason University Student Union
Building Addition 1

Fairfax, VA

General Contractor:  Hess Construction
Architect/Engineer:  Grimm + Parker Architects and Shapiro & Duncan, Inc.
Contract Amount:  $6,119,823
Start Date:  10/29/2009
Completion Date:  7/8/2011


This design/build project on the Fairfax, VA campus of George Mason University presented multiple challenges. The project included design and construction of HVAC and plumbing systems for a four-story, 74,000 square-foot addition to Student Union Building #1, along with the occupied phased renovation of the 85,000 square-foot existing facility.

To begin with, our design/build team did all of the mechanical and plumbing design in-house. This required nine months of up-front design work prior to the start of onsite work. As part of this process, we participated in numerous face-to-face and virtual meetings with the architect to examine design constraints and ensure that we could provide workable solutions.

In addition, we had to fully comply with the owner’s design manual and end user requirements related to work space environment, office layouts and architectural aesthetic.
Another challenge was to coordinate the work of our team with the architect and other trades including electrical, fire/sprinkler and structural.


The addition building is serviced by two new variable-speed modular air handling units, each with energy recovery wheels providing conditioned air to variable air volume (VAV) boxes with reheat coils throughout the building. The building is served by high temperature hot water and chilled water produced at a central campus facility and delivered to the building; this required site work to bring the utilities into the building. New plumbing consisted of bathroom groups on each floor, serviced by a new domestic water booster pump and water heaters.

Work in the occupied phased renovation areas consisted of demolishing the existing 40-year old HVAC multi-zone air handling units and ductwork, and replacing the systems in phases with new VAV air handling units servicing VAV in the private and public spaces.


Our team successfully met the 18-month construction schedule for the addition and the nine-month schedule for the renovation. The project was completed in time for the start of the 2011-2012 academic year. Already, the expanded and renovated space is proving itself to be up to the task of meeting the growing student service facility needs of George Mason University.