Masonry Magazine May 2012 Page. 21
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READER SERVICE #149
May 2012 MASONRY 19
The new arch
The molding process was extremely complex, as the one-piece cast stone arch incorporated numerous architectural details, including rosettes, surround profiles, decorative panels, and false joints all into the same mold. Therefore, the mold was fabricated out of a combination of materials that included wood, fiberglass and rubber, in order to be able to replicate the fine architectural details as well as to be able to "de-mold" the element after casting.
"Cast stone was also effective in terms of flexibility in design," says Jeff Frake of Masonry Preservation Group. "[The project team was able to make design changes and improvements that we would not have otherwise been able to do with natural stone." (See the cover of this issue for another look at the finished project.)
JOSEPH P. KINNEARY FEDERAL COURTHOUSE - COLUMBUS, OHIO
Built in 1934, with funding from the President Franklin Roosevelt Public Works Administration economic recovery program, the entire façade of the building is sandstone, taken from a quarry in northern Ohio in 1932. The huge, seven-story building is undergoing a complete exterior renovation, with cast stone replacing the original sandstone. The Ohio Historical Society is involved with the project, along with the architect, to ensure that the cast stone is produced in such a manner that it will be an exact match to the existing sandstone, to maintain the integrity of the original design.
Phase 1 of the restoration has begun involving the replacement of the sandstone on the top three floors with cast stone as the material of choice, due to its versatility in color, texture and shapes for the stones. To ensure that the texture was correct, multiple pieces from the building were delivered to the cast stone manufacturer's plant, and then castings were made from each of them. The samples made from the castings show the striations and blending of colors in the cast stone, creating just the right look. In addition to color and texture, each original stone, when removed from the building, is numbered, a mold is produced, and the stone is cast with exactly the same look and size as the original.
Cast stone will replace original sandstone.
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To add to the complexity of the project, the Federal Courthouse will continue to be in session, requiring all of the work to be performed from 6 p.m. to 4 a.m. only. This includes everything from demolition and shipments to installation. Given the location in Downtown Columbus, one elevation is bordering a river, two elevations have road frontage, and one elevation has a city park connected to the property. The location also affords little on-site storage, so communication among all team members is vital.
Jan Boyer is executive director of the Cast Stone Institute, serving on the boards of directors for The Masonry Society and the Masonry Alliance for Codes & Standards. She has been involved in the masonry industry for more than 14 years and can be reached at jboyer@caststone.org or 717-272-3744. For a list of certified Cast Stone producer members, visit www.caststone.org.