Denver, Colorado (3/10/2003) --- When the Georgia World Congress Center (GWCC) in Atlanta, Ga. added 1.6 million square feet including a ballroom, two auditoriums, 29 meeting rooms and 420,000 square feet of new meeting space, they knew they needed a roofing system on which they could rely. According to Jerry Lewis, the GWCC Director of Engineering, one drop of water in a booth can destroy the business of an exhibitor. It is not a chance the GWCC is willing to take.
"We take our roof systems very seriously," Lewis said. "We are an international convention center, open 24 hours a day seven days a week, 365 days a year. For each exhibitor, we only get the chance to shine one or two times a year. The nature of our business requires we have and maintain very good roof systems."
After soliciting bids from several roofing contractors, Hardin Russell Mitchell, construction managers, in cooperation with Construction Services, Inc., the roofing contractor, selected multiple Johns Manville roofing systems for the project. Johns Manville had provided the roofing system for two previous convention center expansions.
A JM 4-ply built-up roofing (BUR) system was selected for the 573,000 square foot exhibit hall and related areas and a gray UltraGard® PVC SR60 membrane for the 150,000 square foot barrel shaped ballroom and main concourse. For the BUR portion of the roof, two inches of E'NRG'Y™ 2 polyisocyanurate roof insulation was mechanically attached to a metal deck. This was overlaid with ¾-inch Fesco® Board insulation. Tapered Fesco Board pre-cut crickets were used between the drains. After the joints were taped with fiber glass roof tape, four plies of GlasPly® Premier felt were hot mopped in asphalt. The roof was finished with gravel. A DynaFlex® modified bitumen sheet was used for the flashing details. Expand-O-Flash® exterior covers were used for expansion joint openings.
According to Mike Yellott, chief estimator for Construction Services Inc., a gray PVC roof was selected to cover the barrel shaped ballroom and main concourse because it would be visible from the ground and would be easier to install. The single ply portion of the roof consisted of a 2.8 inch layer of ISO 1™ polyisocyanurate insulation board over a metal deck. Tapered ISO 1 crickets and prefabricated roof drain diverters were used in various locations to assist with drainage.
"We needed to add the diverters to deal with the concourse roof as it slopes from a high to a low point," said Ed Stripling, senior associate Heery/TVS Joint Venture. "We added diverters every 30 feet to collect water in scuppers on the back side to minimize the amount of water that will end on the low side."
Stripling said another unique feature of the project was the 100-foot high glass walls that go past the roof edge. These were roofed to the system over the back of an aluminum framing system. A coping was used to cover it up.
Near the end of the project, bearing pads were installed for more than 2,000 lightening rods on the building. According to Joe Dusek, Senior Project Manager for Hardin Russell Mitchell, these were clamped down with adhesive.
Bill Smelcer, the general superintendent with Hardin Russell Mitchell in charge of construction of the new facility said the greatest challenge on the project was getting such a massive roof down in a timely fashion. This required schedule coordination. He said that both systems were easy to install and maintain. Kevin Clark, GWCC Construction Manager was instrumental in coordinating access to the facility to keep the job moving.
Smelcer had nothing but praise for the job done by Construction Services. "Construction Services responded to tight timeframes and they committed the resources to the job to respond to scheduling changes. They are very reputable, quality contractors," Smelcer said.
Johns Manville, a Berkshire Hathaway company, is a leading manufacturer and marketer of premium-quality building and specialty products. In business since 1858, the Denver-based company has sales in excess of $2 billion and holds leadership positions in all of the key markets that it serves. Johns Manville employs approximately 9,000 people and operates 46 manufacturing facilities in North America, Europe and China. Additional information can be found at www.jm.com.
