CarbonCast wall panels increase R-value, reduce HVAC costs by $700k, prevent mold
- Project University Commons at Georgia State University
- Location Atlanta, Georgia
- Type of Precast CarbonCast High Performance Insulated Wall Panels
- Project Size 777,681 sq. ft.
- CarbonCast Surface Area 375,565 sq. ft.
- Architect Niles Bolton Associates
- Contractor Hardin Construction Group, LLC
- Precaster Metromont Corporation
Georgia State University’s 2,000-bed student housing complex will be the largest privately funded university housing complex in the nation when it opens in fall 2007.
Constructed from CarbonCast® High Performance Insulated Wall Panels, the four buildings in the complex will vary in height from nine stories to 15 stories.
The original design of the exterior walls was brick veneer backed up with six-inch metal studs, batt insulation and a drywall interior. The design team opted to use the CarbonCast precast system for several reasons.
First, it was more economical to replace the metal stud system and brick veneer with an easy-to-install precast wall panel, finished on the exterior and ready to paint on the interior.
Second, considering the complex is located in the humid South, there was a major concern that mildew would form in the building – a major potential liability in a place where students would be living. CarbonCast wall panels greatly reduce the mildew risk because concrete inhibits water penetration. In addition, using the precast wall panels eliminated the drywall, eradicating any potential food source for mildew and mold.
Third, based on ASHRAE 90.1 the effective R-value of the brick, metal studs and batt insulation was 7.1. An improved R-value of 12 was achieved using the thermal-efficient precast wall panels.
This was attained by four inches of expanded polystyrene sandwiched between two 2.5” thick concrete outer wythes which comprised the panels. The inner and outer wythes were connected using thermal-efficient C-GRID® carbon fiber trusses. Carbon fiber grid, unlike steel, has low thermal conductivity, thereby preventing hot or cold spots from forming.
The increased R-value enabled the university to specify a less substantial heating and cooling system, saving $700,000. And cost savings will only increase over time as the annual utility and maintenance costs will be significantly less.
Finally, with a tight deadline, precast concrete, which erects quickly compared to masonry set brick, made perfect sense for the project.
The panels not only made logistical sense, but are aesthetically pleasing as well. On the street level, a brick veneer was used, achieving the same architectural look as the original plan. Further up the buildings, a buff sandblast finish was used. Finally the buildings were topped off with a white sandblast finish. The panels incorporate half-inch reveals.
The CarbonCast panels were fabricated and installed by AltusGroup® member Metromont Corporation from its Hiram, Georgia, facility.