Georgia State Capitol exterior, Atlanta

  Then the ceiling fell in, literally. A large piece of ceiling plaster came down outside a major office, redirecting efforts toward repairing and rehabilitating the building’s public spaces.
  Since 1997, the public areas of the structure have undergone a substantial amount of work, including the cleaning and reinstalling of 48,000 ft² of marble floor tiles. More recently the focus has moved to the exterior of the limestone structure.
  Now, some $65 million later, Georgia officials are pleased with the work, but they’re also eyeing going back to the master planning process to guarantee a centuries-long future for their seat of government.
  As work was wrapping up on the renovation of the public areas on the interior of the building, attention turned to the capitol’s exterior. Despite a cursory pressure wash before the 1996 Olympic Games, the building suffered from smog, bird droppings, errant roofing tar and fungus.
  Mary Catherine Martin, AIA, an architect with Atlanta-based Lord, Aeck & Sargent and a masonry restoration specialist, says while maintenance records for the structure are incomplete, it seems little had been done on the rotunda since it was reconstructed in the 1950s.
  She adds that much of the work that had been done on the bulk of the Indiana oolitic limestone structure appears to have been inappropriate, even damaging.
  “A great deal has been learned about the treatment of historic masonry structures and the importance of understanding the properties of the original materials,” she says. “Some of the earlier repairs to the capitol were executed prior to that knowledge base being developed.
  “We know that certain sealants and high strength mortars can be very damaging to historic structures. Unfortunately, some very well-intentioned repairs were performed on the capitol with some inappropriate materials.”
  Armed with the previous photographic survey of the building, the architects prepared drawings of every surface, noting existing damages and what needed to be repaired. Then, as with the interior tile restoration, Martin and the construction manager prequalified possible subs for this part of the job. A total of three possible contractors were identified, with the winning bid submitted by Snellville, Ga.-based Southern Preservation Systems.
  Jan Phillips, SPS project manager for the capitol, says the company specializes in building and parking deck restorations. As a specialist in historic preservation, Phillips says she was particularly interested in the challenges the capitol’s exterior presented.
  “We were required to use the original materials, which are the lime-based putties,” she says. “Even though the rotunda was built in the 1950s, it still required a lime-based product.”
  First, however, the building had to be cleaned. Martin says following some field trials, the decision was made to scrub the surface initially with a mixture of unscented laundry detergent, household bleach and tri-sodium phosphate (TSP). The mix is a good fungicide, Martin says.
  After that had been done, the remaining stains were documented and the decision was made on whether to attack them using more-rigorous means.
  “Some 90 percent of the remaining stains are calcium sulfate stains that are common on calcium-carbonate stones, because they react with sodium oxides in pollution,” Martin explains. “If it’s a stain that was not damaging to the stone, we’d leave it; but calcium sulfate stains actually form a crust on the surface of the stone that may hold water that can go through the freeze-thaw cycle and start to deteriorate the stone, sometimes causing spalling or cracking.”
  In those cases, the contractor was instructed to use a special wet gun for wet blasting, although not to the point where the stone surface was abraded. Hand chisels were used to remove the roofing tar. Only when the surfaces were clean did work begin on repairing the stonework.
  “Our work consisted of removing all of the unsound or inappropriate mortar, then cleaning them because there couldn’t be any mortar left in there,” Phillips says. “Then, when it was all cut out, it was inspected. Then, we had to go in and fill any voids and built it up so we had a square back. Then we’d build out the joint and leave a sixteenth-inch recessed.”
  In addition, Southern did patching of holes or other damage to the limestone, as well as to the courses of ornate decorative work.
  For the base of the structure, where work began in 2001, Southern had a crew of about 15, Phillips says. Work on the rotunda reduced that crew to about eight.”
  Both Phillips and Jeremy Colbaugh, a project manager from The Winter Construction Co., which was hired to serve as construction manager, say the biggest challenge with the building’s exterior, aside from the cleaning, has been working with the lime-based putty.
  “It’s rare to find someone who specializes in that,” says Colbaugh. “The softer material is important because it allows for expansion of the building. The company that made the lime mortar came out and did a training session so everyone got familiar with the process and the tools that were used.”
  Martin agrees that there were some challenges at first, but both she and Phillips are pleased with the results, which were completed in November 2003.
  “I think that Southern Preservation Systems really rose to the standards I set for them,” says Martin. “I think we ended up with an excellent job.”
  “It was a big project,” says Phillips. “But, because we were able to work with Winter and the architects, it was well defined for us, and it went pretty easily. We’re really detail-oriented and things went pretty well for us.”
  Gena Abraham, former project engineer for the Georgia Building Authority (the agency responsible for the public portions of the capitol, says she’s pretty satisfied with the way the project went, despite feeling at times, “that it was my cross to bear.
  “It was a rough road and everyone made some mistakes, but overall it was a true pleasure to be involved in it,” says Abraham, now director for the Georgia State Financing and Investment Commission. “Being part of the restoration effort for your state capitol was a really rewarding process. We had a good team and we’re real pleased with the way it came out.”
  The public’s response has also been positive, she adds, with nothing but good comments about the improved appearance of the structure.
  Of course, it’s also not done yet. Susan Turner, AIA, head of the Historic Preservation studio for Lord, Aeck & Sargent, has been involved with the project since the inception of the master planning process. While the work has been completed on the public areas of the building, Turner notes that nothing has been done on the balance of the structure, which includes offices and committee rooms.
  “Because of the alterations and renovations that have been done to the building through the years and the systems that have been added in a very ad hoc way, it’s become very unorganized,” she says. “It’s apparent the building needs to be thought of in a very holistic way.”
  Fortunately, Turner says the legislature has approved funding for a master plan for the building. And, in another positive sign, she adds the Georgia Building Authority has asked the architects to develop a maintenance plan for the structure.
  “We’re going to start that effort,” she says, referring to the master planning process. “Until we know the scope of the overall project, it will be impossible to predict when it will end.”

This article first appeared in the March 2004 print edition of Stone Business. ©2004 Western Business Media Inc.