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Slippery rock Gazette Pinnacle L May 2020 | 11
Commercial Exterior
Grande Arche de la Defense
Paris, France
ocated on the edge of Paris, the Grande Arche de la Defense is the work of Danish architect Johan Otto von Spreckelsen. Completed in 1989, the resolutely
modern design of “the window on the world” resembles a giant minimalist door frame.
The concrete, granite, marble, and glass arch houses a restaurant and event spaces and is a modern workplace con- taining 35 floors of office space. It’s also gigantic—large enough to fit the Notre Dame Cathedral inside its 348-foot span and 361-foot high rooftop terrace. While beloved for its striking design, the exterior of the structure began to show signs of serious deterioration only three decades later.
The Arche was originally clad in Italian marble, but that stone proved too porous, succumbing to the effects of climate and acid rain. Recently prin- cipals on the project noticed that the exterior Carrara marble was deterio- rating at an accelerated rate. Drastic changes in temperature were causing extensive cracking and spalling. The restoration team scoured the world to find the right stone to reclad the structure and found a natural choice in the flawless character, even grain, and purity of color of white Polycor Bethel White® granite, quarried in Vermont.
Up close granite and marble are clearly two different stones, granite hav- ing a more variegated interlocking crystalline structure and marble a milk- ier composition, usually with more veining. A detail photo of the granite shows how the pinhead taupe grains are slightly visible up close, but from a distance visual blending registers the surface as a pure white. The result is a clean and sleek white surface with no worries of durability.
Please turn to page 13
 Award of Excellence
            Natural Stone Institute Member Company
Polycor Inc. Quebec City, Canada Stone Supplier/Fabricator
Other Project Team Members
Valode & Pistre
Architectural Restoration Team
EDM Paris Uni-Marbres S.A. Stone Installers
Granitos Ibericos Levantina Stone Suppliers
Bethel White® granite
Judges Comments:
The jury was encouraged that stone was cho- sen as the new cladding material for this piece of iconic architecture in Paris. It is very compelling that the monolithic, heavenly nature of the arch with the original Carrara marble was still possible to achieve with the Bethel White® granite. The jury also appreciated the amount of coordination needed to achieve the replacement of the stone, for such a beloved landmark.

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