The Denver office of architecture firm Gensler specified 120,000 square feet of Eastman, Ga.- based Alcoa Architectural Products’ 4-mm Reynobond aluminum composite material (ACM) with a fire-retardant core and Anodic Satin Colorweld 500XL finish to retrofit Colorado State Bank and Trust in Denver.
The Colorado State Bank and Trust building has stood at 1600 Broadway ushering financiers, artists, retailers and tourists into Denver’s central business district for more than 40 years. Alcoa Architectural Products matched the existing 11-year-old panels even though the color was no longer a stocked finish.
The architectural team needed a lightweight cladding that would not affect the building’s structure to replace the aggregate precast cladding. Jeff Hall, Gensler, says the main goal for the project was to renovate the exterior appearance with a lightweight material that would not affect the structure. “Metal was a good choice-it wrapped the existing shape and form of the building well, it has the right aesthetic and provided an economical solution for the retrofit,” he explains.
Elward Systems Corp., Lakewood, Colo., engineered an adjustable, two-piece-clip, sub-frame system to secure Reynobond ACM panels and plumb up existing columns. The panels were used to encase the existing columns of aggregate concrete, as they could not be attached directly to the aggregate stones. At the top, the columns appear to hold up the crown of the building. The cornice required hot air welds and custom fabrication to create the shape.
Reynobond ACM panels were the desired lightness, formability and cost, and the panels blended with a partial metal over-clad of Reynobond panels that was added to the building base in 2003. Denver-based Gen 3 Architectural Wall Systems installed the Reynobond ACM panels in an ESC routand- return rainscreen supplied by Elward Systems.
Nine U-shaped swing stages were used to access the columns of the structure and seven standard modular platforms were used to feed materials to the stages. The Reynobond ACM panels, which averaged 3 feet by 12 feet in size, were installed from floor to floor.
The work site was small and in a highly trafficked area. Much of the preliminary work was done at night and on weekends to ensure pedestrians were not endangered by falling concrete loosened by workers installing the sub-frame system. Crews of 25 to 30 people worked in two shifts to complete the project in six months.
Alcoa Architectural Products, www.reynobond.com
