Legacy Union is a 33-story Class A office building and serves as the first of multiple buildings on a 10.2 acre development in downtown Charlotte, North Carolina. Built on the former site of the Charlotte Observer, this 850,000 square foot LEED Gold Certified office structure stands at a height of 632 feet and is coupled with two adjacent parking structures.
LS3P and Gilbane Building Companies solicited the assistance of Camarata Masonry Systems, Ltd. (CMS) in the material selection and value engineering options as the initial selections and design was substantially over budget. The teams traveled to Italy and reviewed various white and black stones that could be used on the project before the architect and owner eventually selected Pietra del Cardosa sandstone, Statuario C marble along with Gascogne Blue limestone. The team returned to Italy in June of 2017 to finalize and approve the range of the selected materials. In order to ensure that the raw material was readily available within the desired color range, once the shop drawings were completed, the owner elected to purchase the stone blocks in advance of releasing material for fabrication. Ultimately, the project required the preparation of shop drawings and engineering calculations and the installation of 23,600 square feet of wall cladding and 34,400 square feet of paving.
During early discussions with the design team, it became clear that the focus would be on the smallest of details required by the balanced interior design. The symmetry of the wall and paving design carries throughout the lobbies and on multiple levels. The layout of the walls and niches required precision in order to properly interface with the radiating bands within the radial paving pattern (as shown on Drawings P2 and P3.7 in the Supplemental Material section). Any error in locating the wall cladding (which preceded the paving) would have been obvious and disastrous. The difficulty in the layout of the radial pattern was compounded by the building’s concrete core walls, which made it impossible to use the center point. As such, extra time was given to ensure that the final layout was correct for the full 360 degree lobby. This effort paid dividends during the installation, as the wall cladding interfaced with the paving perfectly and exactly as envisioned by the design team.
The outer radial walls are clad with Gascogne Blue limestone wainscot and have Pietra del Cardosa base and trim at all niches and openings. The wainscot and portal surrounds required detailed coordination with the millwork to ensure proper alignment with both vertical and horizontal jointing between materials. The center core walls are clad, full height at Level 1 and 2, with the Statuario C marble. All Statuario C wall cladding was dry laid in Italy to provide assurance of a well-blended finished wall. As the Statuario C wall cladding was set, a 4 foot high plywood clad standoff partition was built throughout the core of the building to protect the stone from other ongoing lobby work. The paving is also a combination of the honed Pietra del Cardosa in radial bands infilled with radial cut honed Gascogne Blue. The radiating bands of Pietra del Cardosa paving were installed as lead rows, for layout and elevation, followed by the infill of the cut to size radiused Gascogne Blue pavers.
At the east and west entries, the 35 foot high storefronts are bordered with cubic sculptured Pietra del Cardosa. These 4’ wide x 3’ tall x 7” thick pieces, weighing approximately 750 pounds each, were installed vertically at each jamb and across the head/soffit of each of the storefronts, sloping outward at a 45 degree angle. Due to the size, weight and configuration of these pieces, careful coordination was required with the tube steel supports and sheathing that was put in-place approximately one year prior to the stone installation.
The completed project is a successful beginning as the centerpiece of a development that has been targeted as “the honoring of past legacies and development of future ones in downtown Charlotte”.