When the Georgia Institute of Technology (Georgia Tech) decided to design its new building as a “Living Building,” the project team knew they had to be extremely thoughtful in their design choices and building materials selections. The Living Building Challenge is the world’s most ambitious green building program and requires that projects meet 20 rigorous performance requirements throughout the construction process and for a full year after completion. Made possible through a partnership with the Kendeda Fund, the new Kendeda Building for Innovative Sustainable Design is the first academic and research building in the Southeast to attempt this certification and is designed to use one-third the energy of a comparable building.
With a combination of great insulation, energy-efficient systems, and a rooftop solar array, the 46,800-square-foot Kendeda Building is engineered to actually produce more energy than it consumes. The roof is also designed to capture rainwater for collection into a 50,000-gallon underground cistern where it is filtered for reuse throughout the building, including as drinking water. The building’s roof is also host to a 1,000-square-foot accessible roof deck and a 4,300-square-foot rooftop garden with a honeybee apiary, pollinator garden, and blueberry orchard.
The photovoltaic array is comprised of 913 solar modules covering approximately 15,860 square feet of area, with a total capacity of 330 kW. It forms a floating canopy above the building. The panels will tilt from the horizontal plane by 5 degrees to face south. This slight adjustment increases solar exposure and improves drainage.
As you can imagine, a roof with so many functions demands the use of only the most exacting roofing products. The project team chose a 3-inch base layer of non-halogenated polyiso roof insulation to cover nearly the entire roof and approximately 13,000 square feet of thermoplastic polyolefin (TPO) membrane. GAF supplied the polyiso insulation and 60-mil EverGuard Extreme TPO roof system for the project, and it was installed by Roof Management Inc., headquartered in Norcross, Georgia.
The design team also chose to direct rainwater into capture systems by the judicious use of tapered insulation over the flat material, which created the proper rooftop slope and drainage.
Even without this water catchment system, tapered insulation can be a very beneficial design feature for low-slope roofs. Ponding or standing water can add enormous stress to a building’s roof and lead to premature failure of roofing materials if water stands on the roof surface for more than 48 hours. If unaddressed, frequent ponding of water can lead to serious problems such as structural deflections of the roof deck, the growth of bacteria or unwanted vegetation on the roof, and can ultimately cause water intrusion into the building that can be costly to remediate. That the Kendeda Building roof can use this design to also collect water for reuse is an added bonus.
The Living Building Challenge specifies that materials in Living Buildings should avoid the use of certain chemicals. Polyiso insulation products manufactured with non-halogenated flame retardants satisfy this challenge while offering superior performance.
- Polyiso insulation offers superior performance qualities, including:
- High R-value per inch compared to other types of insulation of equivalent thicknesses.
- High moisture resistance.
- Improved fire resistance.
- Lightweight boards for easy handling and installation.
- Blowing agents with zero ozone depletion potential and negligible global warming potential.
Beneath its carefully designed roof, the building holds classrooms, laboratories, offices, an auditorium, and a student commons. But the educational mission of the building extends beyond these learning spaces. The entire project — from its low-waste construction to its low-consumption energy use — offers unique learning opportunities for designers, builders, and building operators, such as how a building’s design can conserve energy and water while mitigating a region’s humidity and potential droughts.
The Living Building Challenge is organized into seven performance areas — one of which addresses the materials used on a project. New building projects are required to include one salvaged material per 500 square meters of gross building area, which worked out to 10 salvaged materials for the Kendeda Building. These included the following:
· Slate shingles: The project acquired a number of pallets of gray slate shingles when the aging roof of the Georgia Tech Alumni Association was renovated. These singles were used as tile on the walls and floors of showers and restrooms.
· Nail-laminated floor decks: 500 10-by-6-foot nail-laminated floor decks were created from two-by-fours salvaged from movie sets, including those form the show “24” and movie “Rampage,” with support from the Georgia Works training program.
· Heart pine joists: 140-year-old Tech Tower provided heart pine joists that serve as treads for the Kendeda Building’s monumental staircase.
· Lumber from felled trees: George Tech’s ground crew helped by collecting fallen trees across the campus, which were then turned into lumber used to make counters and benches.
· Granite curbs: Atlanta’s old State Archives Building provided granite that was used for curbs in the landscaping.
· Wood boards: A former church in Atlanta was the source of the wood that can be found on some of the decorative wall as well as the lobby’s ramp.
The Living Building was designed by a collaboration between Lord Aeck Sargent and the Miller Hull Partnership, constructed by Skanska, and funded through a $30 million grant from The Kendeda Fund, one of the leading philanthropic investors in civic and environmental programs in the Atlanta area with a commitment to ecological and social causes.
Certification by the Living Building Challenge 3.1 is anticipated in 2021, and the project is also pursuing the U.S. Green Building Council’s LEED certification at the Platinum level.
About the author: Justin Koscher is the president of the Polyisocyanurate Insulation Manufacturers Association (PIMA), a trade association that serves as the voice of the rigid polyisocyanurate insulation industry and a proactive advocate for safe, cost-effective, sustainable and energy-efficient construction. For more information, visit www.polyiso.org.
General Contractor: Skanska USA, Atlanta, Georgia, www.usa.skanska.com
Roofing Contractor: Roof Management Inc., Norcross, Georgia, www.roofmanagementinc.com
TPO Membrane: EverGuard Extreme 60-mil TPO, GAF, www.GAF.com
Insulation: EnergyGuard Non-halogenated (NH) Polyiso Roof Insulation Board and EnergyGuard NH Tapered Polyiso Roof Insulation, GAF
Vapor Retarder: GAF SA Vapor Retarder, GAF
Insulation Adhesive: OlyBond500 Insulation Adhesive, OMG Roofing Products, www.OMGroofing.com
Cover Board: 1/2-inch DensDeck, Georgia-Pacific, www.buildgp.com
Solar Panels: X-Series X22-360-COM, SunPower, https://us.sunpower.com