Architects Smallwood, Reynolds, Stewart, Stewart & Associates (SRSS) of Atlanta needed to specify a weatherproofing sealant with excellent adhesion that would not stain the granite panels inlaid into the building's 21-story glass curtainwall. General contractor Hardin Construction had a very short build-time and wanted to make sure the job got done on schedule with high-performance sealant products that had a solid track record for durability.
Building Sealant Meets CriteriaDow Corning 756 SMS Building Sealant got the nod after receiving a recommendation from curtainwall contractor JAMCo.
"We had not used 756 SMS before," said Demetre Rizopoulos, the SRSS architect responsible for construction administration on the project. "JAMCo recommended it, the AAMA 501.1 water test was performed and everything passed."
According to JAMCo Project Manager Bill Hahn, the company sent substrate samples to the Dow Corning Lab for adhesion testing prior to the start of the job after their Dow Corning representative first suggested it for the project. JAMCo then recommended the sealant as an alternate to the specification for 171 17th Street Building, the first tower to go up in a large mixed-use development known as Atlantic Station.
Field testing for cohesive failure was performed when the installation was about 50% complete. Three water tests were also performed later as the project neared completion. SRSS witnessed both the pull tests and the water tests.
Kudos from the FieldJAMCo has high performance standards for the products they use, and 756 SMS has met them on this project, according to Hahn.
"JAMCo uses Dow Corning products exclusively for our silicone needs," he said. "We're very pleased to add 756 SMS to our lineup."
The sealant received good reviews from the field as well. "I like 756 SMS," said Mike Allen, site superintendent for Alpha Insulation and Waterproofing, a subcontractor to JAMCo. "It skins quickly and bonds great to stone and metal. It has excellent adhesion and nothing required primer."
Alpha's 12-person crew applied about 2,000 gallons of gray 756 SMS Sealant to the building's exterior perimeter joints. It took about five months to weatherseal the nearly 60,000 square feet of granite panel inlays. The building was completed in April 2004.
Other Dow Corning Sealants Also SpecifiedCommonly referred to as the South Trust Tower (after its anchor tenant, the South Trust Corp.), the building's facade required about 100,000 total lineal feet of caulking. All joints were prepped with a solvent wipe; some required backer rod or bond breaker. Rizopoulos specified other well-established Dow Corning sealant products for this project, including:
- 790 Silicone Building Sealant: 16 gallons were applied to the building's lower pre-cast joints.
- 791 Silicone Building Sealant: About 4,000 tubes were applied to the internal curtainwall.
- 795 Silicone Building Sealant: 1,000 gallons were used on glass-to-glass and glass-to-metal perimeter joints.
- 995 Silicone Structural Sealant: 200 gallons were used on the penthouse upper screen wall.
"We specify Dow Corning sealants on all our projects because they have a proven track record," said Rizopoulos. "We find products that work and stick
About 756 SMS and Atlantic Station756 SMS Building Sealant features patent-pending surface-modified silicone (SMS) technology that sets new standards for clean sealants. With its unique, matte finish, 756 SMS is a high-performance sealant that features low staining, low dirt pickup (compared with other silicones) and superior unprimed adhesion to both common porous substrates and painted metals.
Located in the heart of Atlanta, Atlantic Station is a "live-work-play" urban redevelopment project that will eventually encompass 138 acres. It will provide a mix of middle-income and upscale housing for 10,000 residents; world-class restaurants, theaters and retailers; and over six million square feet of office space.