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Nestled on the campus of Temple University in Philadelphia, PA, Charles Library is one of the country’s most modern and significant new library constructions in recent history. With a design that pushes the limits of creativity, the library fulfills the architect’s intent to spur imagination and inspire excellence. Key to the building’s striking design is Mesabi Black® granite from Coldspring, specified for exterior cladding, windowsills, soffits, coping and a green roof wall facade.

Coldspring worked hand-in-hand with the architecture firm Snohetta of New York to meet the design intent. The architect visited Coldspring’s Mesabi Black quarry in Babbitt, MN, before the project’s start to view numerous mock-ups of the material and finish options. “The architect reviewed several material options in the early design review and Mesabi Black became the leading consideration early on in the process,” explained Duane Krueger, regional sales manager for Coldspring. Additionally, during the project design phase the architect visited the production facilities to view material mock-ups to gain a greater understanding of the color range, natural characteristics, physical properties and review the various finish options, according to Krueger.

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Each piece of granite, measuring approximately 6 inches wide, 4 feet long and 2.25 inches deep, features rustications or reveals. Photo courtesy of Coldspring

Vertical sections of the granite in a split-face finish clad the library’s solid base and coordinate with the existing campus landscape. A total of more than 30,000 square feet of granite pieces – each featuring rustications or reveals – were successfully produced with manufacturing skill and quality.

“To keep the costs of the rusticated pieces within the owner’s budget, we evaluated our processes from the outset to develop production efficiencies,” said Krueger. “The architect had a good idea of what they wanted for the project material design and that it consist of a medium gray color with a textured finish. The challenge was to find the appropriate color tone and finish that would meet the intended design concept within the project budget. The process included an extensive sampling process, mockup reviews, material orientation (fleuri or veine) considerations, review of various finishing techniques and comprehensive pricing analysis to meet the project design and budget.”

Each long slender granite piece for the building’s cladding measures approximately 6 inches wide, 4 feet long and 2.25 inches deep, presenting a challenging installation for the contractor, Dan LePore & Sons Co. of Conshohocken, PA. Because of the stones’ small size, they rely on two points of attachment rather than the typical four. The stone’s installation on a sealant-less, caulk-less rainscreen system allows for water drainage and evaporation, preventing water from penetrating the facility’s interior while lowering the risk of wall rot.

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The challenge was to find the appropriate color tone and finish that would meet the intended design concept within the project budget. Photo courtesy of Coldspring

The team at Dan LePore & Sons laid out the rainscreen’s extruded anodized aluminum grid system at their shop before delivering it to the site. Each aluminum rail measures 30 feet long.

“Plates mounted on the back of the stone engaged with the horizontal rails of grid system to form the mounting system,” said Greg LePore of Dan LePore & Sons. “Our skilled installation team then hung each piece along the building’s complex arcs and curves.”

Mesabi Black granite also provides a key design element for the building’s green roof, where it adorns the facade and coping. The dimensional, 2- x 2-foot granite blocks provided challenging rigging, logistics and installation at the building’s parapet.

A beautiful outcome for a challenging design was accomplished at every stage of the project by the skilled well-coordinated team. Today, Charles Library is a centerpiece of Temple University and the city of Philadelphia where its inspiring design promotes learning, innovation and community.