Water Well Journal
Issue link: http://read.dmtmag.com/i/705618
T wo historic Frank Lloyd Wright buildings near Chicago—the Unity Temple and the Emil Bach House— recently underwent significant restorations to return them to their former glory. Wright offered to design the Unity Temple in 1905 after lightning struck the spire of the wood-framed Unitarian Church, causing it to burn to the ground. Wright's version was a one-of-a-kind church at the time with no steeple and no front entrance. It was also one of the first public buildings to use concrete in the exterior's design. Emil Bach, the president of Chicago's Bach Brick Co., commissioned Wright to build his home in 1915. The compact 1600-square-foot, two-story home had three small bedrooms and a sundeck on the second floor with stunning views of Lake Michigan. The recent restorations to both structures matched the ma- terials and finishes as closely as possible to Wright's original designs, but with a few notable exceptions. One of the biggest is they are now heated and cooled by modern geothermal systems. Gunny Harboe, owner of Harboe Architects in Chicago and lead architect for the projects, often recommends geothermal to clients with historic buildings because the systems stay hidden from view. "When you have to find a place to put these big ugly air conditioning condensers, it's a problem," he says. "As an ar- chitect, I'm worried about the historic fabric of the building. Geothermal systems don't affect your visual ability to experi- ence the house or building as it was originally intended to be." They also offer humidity control, which is critical in old, historical buildings. In fact, Mark Nussbaum, PE, with Archi- tectural Consulting Engineers in Oak Park, Illinois, and the engineer for both projects, believes interior humidity played a role in some of the damage to Unity Temple's exterior. "(Geothermal systems are) able to simultaneously control temperature and humidity," Nussbaum says. "You get that for free, where every other technology requires expending new energy to control humidity." Owners of historic buildings are often set up as not-for- profit organizations, which can apply for grants for geo- thermal and other energy-efficient upgrades. These can be beneficial as they can stabilize energy bills and make it easier to manage a limited budget. But while it might be easy to convince these clients to choose geothermal, no project is without its challenges. That's especially true when the job site is an historic landmark. The Emil Bach House The Bach House, which was designated a Chicago Land- mark in 1977 and placed on the U.S. Register of Historic Places in 1979, is now a short-term vacation rental owned by Tawani Enterprises Inc. The interior underwent a major restoration by the previous owner and Tawani Enterprises hired Harboe Architects to re- store the exterior and add the geothermal system. In previous renovations, the sundeck was converted to a living space, but the restoration removed these changes—so the house regained its original design integrity. The project also included the restoration of exterior masonry, concrete, and stucco. Sub-Surface Geothermal Inc. in McHenry, Illinois, drilled and installed the geothermal loops for the system. They drilled two 500-foot-deep boreholes in the home's backyard and installed standard 1-inch U-bend loops grouted with a bentonite-based thermal grout. The project went seamlessly in Nussbaum's opinion, with only a few challenges. "Drilling conditions here in Chicago are pretty good," he says. "We have a standard 75 feet of overburden, then you get into the soft shale and limestone. Then it gets harder down about 150 feet. They're able to get pretty easy drilling for the first half, then a little harder rock the second half." The site's elevation caused the only challenge on the proj- ect, which was otherwise similar to most typical residential projects. The house was elevated about 8 feet off the primary street and about 2 feet off an alley. MODERNIZING continues on page 24 Geothermal systems bring two Chicago landmarks up to date. By Jennifer Strawn The Unity Temple in Oak Park, Illinois, is currently under a renovation that includes a geothermal system of nine 500-foot boreholes. All photos from Architectural Consulting Engineers unless noted. "Geothermal systems don't affect your visual ability to experience the house or building as it was originally intended to be ." WWJ August 2016 23 Twitter @WaterWellJournl