Capitol Tower Strives for LEED-EB with Roof Replacement Project

Capitol Tower is a commercial office building built in 1986. The eight-story office building and 10-level parking garage is conveniently located in the heart of Austin's central business district near the state capitol, and is within walking distance of all major restaurants and businesses on Congress Avenue.

After more than 20 years, the 120,000 square foot Capitol Tower office building was in desperate need of a new roof. In January 2009, Chamberlin began to execute roof renovations for Capitol Tower Investments, LP. Project goals included finishing the renovations in a tight timeline and achieving LEED-Existing Building Platinum status. LEED certification recognizes high performance buildings in the areas of environmental impact, occupant health and financial return.

Chamberlin began work with the removal of the existing ballasted EPDM roof system. It was replaced with a TPO single-ply membrane system. Compared to other typical single-ply membranes made of EPDM, PVC and TPO, the TPO roofing membrane applied to this project provides the benefits of all three materials combined in a single roofing membrane – low installed cost, heat welded seams and no liquid plasticizers.

As an added bonus, the white reflective color of the energy efficient membrane reflects more solar radiation than the typical black EPDM membranes. This significantly reduces heat load. This "cool" roof will promote lower cooling requirements and ultimately save the owner as much as 20 percent in energy costs.

The new energy efficient, fully adhered roofing system is just part of the multifaceted process required to attain LEED certification for the building. In addition, Chamberlin followed the U.S. Green Building Council's detailed Green Building Guidelines throughout the installation process. A sampling of the guidelines followed include recycling 80 percent of old roofing materials, recycling 140 tons of ballast into roadway base material, recycling 28,000 square feet of expanded polystyrene Styrofoam into insulated CMU masonry blocking, donating 1,000 concrete pavers to Habitat for Humanity for re-use, and increasing the roof insulation thermal resistance from a value of R-6 to R-24.

While closely following the Green Building Guidelines took great care and thoughtful planning, Chamberlin's biggest challenge on the job was material staging and scheduling. Because work was being conducted during normal business hours on a populated office space, special attention was required in order to minimize disruptions. "We adjusted our crew's working hours, sometimes working nights and weekends in order to meet the changing schedule," said Project Superintendent Danny Taft.

Due to the fact the building has several roof levels that can only be accessed through tenant office spaces, Chamberlin mechanics made sure they were not only quiet but also had all necessary materials on hand to avoid disruptions due to multiple trips through office areas.

To further limit tenant disruption, the staging for the entire roofing project was located on the top level of the parking garage, which is just below the first floor of the office building. Two hundred tons of roof debris was removed from the highrise building by hand, and all of the new roof materials were transported to the roof deck via the freight elevator.

"This was not the standard roof replacement project," said Project Manager Andy Seagraves. "It provided a lot of unique challenges. We have enjoyed the opportunity to work with Stream Realty at Capitol Tower, as well as the other trades on the project, to ensure that it not only followed LEED guidelines, but that we also stayed within budget and within Chamberlin's strict safety guidelines."