Concrete Staining Nawkaw Corp., Watkinsville, GA 30677, USA The Atlanta Hyatt, downtown Atlanta, Georgia, was constructed in 1965 and was the first open air atrium hotel in the world. It was constructed under the watchful eye of John Portman, who went on to become one of America’s most successful architects. The hotel boasts 1,260 guest rooms and just over 180,000 square feet of ballroom and exhibit space. Using the construction technology and trends of the time, the exterior surfaces of the hotel were constructed of poured in place concrete panels with exposed river rock aggregate. This was a popular building material, but one that could leave gaps of uneven areas where the aggregates weren’t evenly distributed or exposed at the surface. After years of pollution from busy city streets and mass transportation, the hotel exterior began to look black, making the once majestic hotel appear dirty and unattractive. The building owners began seeking a solution for restoring the building to its original standing, while addressing the missing river rock aggregate.