Architectural fins of perforated metal were incorporated into the design to add shade elements and create visual appeal along the more expansive sections of glass.
When using expanded metal as an architectural feature on a project such as SkySong 3—a LEED Silver-Certified building in Scottsdale, AZ—product pattern, translucency, and installation skill mattered.
Butler Design Group, Phoenix, designer of SkySong 3, and other team members knew the importance of each aspect when selecting expanded metal as a featured component on the glass-clad, L-shaped office, research, mixed-use building.
The 145,000-sq.-ft. building, completed at the end of 2014, is on the 43-acre Arizona State Univ. Scottsdale Innovation Center campus. SkySong 4, an adjacent reverse-image building is set to begin construction in 2015.
In keeping with the City of Scottsdale’s criteria, the team wanted a semi-transparent design element to follow the horizontal roofline on the west and south ends of the “L” and continue around the corners, where it would merge with elongated vertical columns of the same material.
For continuity, the expanded metal also would be applied to the building’s main entry at the inside turn of the “L” and to the adjacent parking garage.
The criteria: The material must provide aesthetics and function without being overly transparent.
“Our concept was to be less transparent when seen from a distance, but more transparent as you get closer to the building,” said Korey S. Wilkes, RA, project manager/architect for Butler Design Group.
The job required close coordination between the steel fabricator Saguaro Steel Industries LLC, Phoenix; Butler Design Group; engineer PK Associates, Scottsdale; general contractor DPR Construction, Phoenix; and city officials; with McNichols Co., Tampa, FL, playing a key role as the metal supplier.
Achieving the concept meant building a full-sized mock up and field testing the material, requiring a forklift to raise the metal sheets to the exact height for test viewing at various angles. The object of the field testing was to determine the opacity and the best positioning for the metal’s diamond pattern to maximize energy-efficient light diffusion while achieving the necessary transparency.
“We needed that vantage point to get a full sense of the appearance,” said Ryan Young, STS, LEED AP BD+C, project manager at DPR Construction. “We all stood back and looked at the shading.”
Because of its transparency when viewed lineally and its opacity viewed from a 90-deg. angle, the team’s solution was choosing standard expanded metal. With its raised lath diamond pattern, they designated McNichols Quality Standard Expanded Metal, plain-steel, cold-rolled, 1/4 #18 standard, 43% open area.
Typically used for screening, ventilating, or security, the diamond-shaped openings permit passage of light, air, heat, and sound. Additionally the sheets are lightweight and easy to fabricate and form.To complement the office structure, the four-story concrete parking garage has expanded metal frames in various shapes and sizes extending from the second to the fourth floor and wrapping the corners.
The assembly of expanded metal sits about 2 ft. from the building’s façade and is attached to square tube-steel frames extending horizontally 110 ft. along and above the roofline on the two ends of the L-shaped building, connecting to vertical columns 48 ft. in height. The material extends an additional 25 ft. from each corner.
With this assembly’s horizontal and vertical positioning, fabrication and installation were challenging, said David Terrell of Saguaro Steel Industries, noting the importance of correct placement of each panel, so the diamond pattern was consistent.
Unlike the flattened expanded-metal pattern, the standard pattern’s diamond-shaped openings have a slightly raised surface. The material comes in a variety of opening sizes determined by the long part of the diamond—3.375 to 0.345 in. The diamond size for SkySong 3 measures 1-in. wide x 1/4-in. tall. Primed and painted red oxide, the expanded metal covers approximately 10,000 sq. ft. of the office building and 5,000 sq. ft. of the parking garage.
“We had to be sure the long direction of the raised diamond pattern was placed horizontally so that the material would all go in the same direction,” said Terrell.The design team wanted a semi-transparent design element to follow the horizontal roofline on the west and south ends of the building’s “L” and continue around the corners.
The available sizes of the expanded metal were 48 in. x 96 in. and 48 in. x 120 in., which influences the configurations needed to meet the architectural intent, so the vertical and horizontal lines were determined by the outline of the sheets. These lines needed to match the lines created by the horizontal floor beams and the vertical and horizontal lines created by the window mullions.
Working hand in hand, Butler project manager Korey Wilkes and Saguaro Steel’s Dave Terrell were able to minimize waste. “We made adjustments, so when we cut a piece of material we could use what was left somewhere else,” said Wilkes. The excess of a 4- x 8-ft. sheet cut to 2 x 6 ft., for example, was reused somewhere else to help keep cost down.
“Dave did a lot of shop fabrication, brought it out in pieces, and then we worked through the details from a dimensional standpoint so we could be sure it would fit into another location,” Wilkes added.
The horizontal sections were shop assembled in 30-ft.-long sections and the columns were shop assembled in 48-ft. sections. The sections were shipped to the site where they were hoisted into place and attached to the structure.
To complement the office structure, the four-story concrete parking garage has expanded metal frames in various shapes and sizes extending from the second to the fourth floor and wrapping the corners.
The parking-garage features were shop fabricated at Saguaro Steel in two sections, an upper and lower, with the largest sections measuring 16-ft. tall by 40-ft. long. At the elevator shaft there are two mirrored slender frames wrapping the masonry shafts consisting of compound-mitered corners to create a three-dimensional shape.
To add other shade elements and create visual appeal along the more expansive sections of glass, Butler incorporated architectural fins of perforated metal. The architectural fins, staggered vertically along the glass, were fabricated by Saguaro Steel from McNichols Quality Perforated-Metal, round-hole, plain-steel, cold-rolled, 3/8-in. holes on 9/16-in. centers, staggered pattern, and a 40% open area.
Like the expanded-metal trim element, the metal fins—the largest measuring 12-in. wide x 24-ft. tall, and smallest measuring 7-in. x 12-ft. tall—serve a dual purpose. With its 40% open area, the element provides slight shade with a decorative flair.
“We do a lot with steel and metal fins in vertical and horizontal application,” said Wilkes. “It provides dynamic and aesthetic elements, with the intent that they serve to break up the massing of the building.”
Butler Design Group used the same perforated metal on the I-beam structured exterior canopies, which were geometrically shaped to fit inside the right angle produced by the building’s L-shaped structure and where the main lobby entrances are located. The canopies were strategically placed above the first and fourth floor at the entrance to provide another element of solar control and design detail.
SkySong 3 combines aesthetic appeal and gains LEED points from its perforated-metal accents. Besides the high-efficiency design and systems technology that helped achieve energy cost savings of 24%, SkySong 3’s Silver LEED certification required more than 33% of the total building materials to be specified and manufactured using recycled materials. McNichols metals include post-consumer and post-industrial recycled contents.