Take a drive along Heather Street in Manchester, New Hampshire, and you will find not one, but two Frank Lloyd Wright-designed homes: the 1950 Zimmerman House in his Prairie School style, and the 1955 Toufic H. Kalil House, a rare Usonian Automatic design. The latter home, held in the family for almost 65 years, will soon be sold for the first time ever.

The location of two Wright-designed homes on the same block is hardly a coincidence. Dr. Toufic Kalil and his wife Mildred were so inspired by the home of their friends, Dr. Isadore Zimmerman and his wife Lucille, that they commissioned Wright to design a home for them as well. The Kalils desired a simple and functional house; Wright's answer was one built using his self-designed Usonian Automatic Building System (UABS), a method of construction using prefabricated masonry blocks.

Philippine mahogany paneling contrasts with concrete block walls and stained concrete floors. " layout="wide" credit="Photo courtesy of Paula Martin Group at Keller Williams" photoUserId=""/>

The UABS method is modular by design, completed by stacking molded concrete blocks without traditional mortaring techniques. Instead, the structure is reinforced with rebar placed in semicircular grooves running around each block; later, cement is pumped into the remaining cavities. The name Automatic comes from Wright's original hope that homeowners could save money by building with the UABS method themselves. However, that proved a difficult task with each block weighing a reported 220 pounds, requiring contractors to build most of the Usonian Automatic homes.

The Kalil House is designed around a two-foot grid floor plan, with the walls built using 4" x 1' x 2' blocks and the ceilings using 2' x 2' blocks. An estimated 4,800 individually cast rectangular blocks were used for the project. The home cost an estimated $70,000 to complete in 1957, proving the method to be more expensive than Wright had hoped.

Reportedly, Dr. Kalil had a special machine built that "created each block under pressure, allowing the blocks to be removed from their forms immediately enabling the start of the next block." In remarkably good condition, the 1,400-square-foot residence offers buyers two bedrooms and two bathrooms, as well as a small detached studio in the backyard.

"This house was kind of their Shangri-La,” says Steve Kalil, the nephew of Dr. and Mrs. Kalil. “It’s pretty special. The decision to sell it was not easy at all. My siblings and I have taken extreme care to preserve the house in its original condition.”

Although many were designed, the Kalil House is the fourth of only seven homes built using the UABS method; two others are located in Phoenix, Arizona, another is in Washington state, and the rest are scattered in the Midwestern United States. Continue scrolling to see more of this rare property, which will officially hit the market in October.

117 Heather St in Manchester, New Hampshire, will be officially listed in early October for $850,000. For more information, visit the listing website or contact Paula Martin of the Paula Martin Group at Keller Williams.

Know of a home for sale or rent that should be featured on Dwell.com? Find out how to submit to Dwell.