The National Park Service Historic Preservation Training Center (HPTC) deployed a lifting system from Oklahoma-based Vacuworx to set 46 new Missouri limestone slabs, topping out at 2,400 lbs., during the recent White House South Portico stairway reconstruction.
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| New South Portico steps, derived from a southwest Missouri limestone deposit, were set with the MC 5 Vacuum Lifting System. The diesel-powered device (top, right) pulls a vacuum between lifting pads and objects to be placed, securing a positive seal. The new steps replace similarly composed pieces placed in 1952. PHOTOS: Vacuworx (perspective), National Park Service (vintage) |
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“With the [machine’s] remote operation, we can safely pick up and maneuver materials without compressors, hoses or other accessories presenting trip hazards,” says HPTC Exhibits Specialist Jessica Gordon. “Everything is self-contained in one unit.” Vacuum lifting eliminated the need for hoisting and placing the steps and stones by strap, she adds, and also mitigated risk of chipping the limestone pieces. The 10-in. long x 7-in. deep x 20-in. wide steps and 11-ft. long, 7-in. thick and 6-ft. wide landing stones were cut from block quarried at Phenix Marble Co., Springfield, Mo.
Based in Fredericak, Md., the HPTC rented the Vacuworx MC 5 lifter and three custom pad assemblies from Extreme Seal & Rigging, Warrenton, Va. Rental options suit the agency, Gordon notes, whose Masonry, Woodcrafting and Carpentry divisions handle 35 to 40 projects a year, typically in the $50,000–$400,000 range. The South Portico project entailed dismantling of a Truman-era staircase, and overlapped a $3.4 million interior remodeling effort at 1600 Pennsylvania Avenue.