They never actually wanted a house. But after a chance sighting and an architectural reincarnation, Tricia Stuth and Ted Shelton, founders of Curb, ended up with three.

The couple, both architects and professors at the University of Tennessee, originally planned to buy a commercial building near Knoxville’s newly energized downtown and turn it into loft apartments. They knew they needed rental income from tenants to finance the type of project that would challenge their architectural skills and provide a home at the same time. But by the time they started shopping for downtown real estate in 2004, they were too late to do anything on a modest budget.

So they started pushing their boundaries outward and reconsidered more traditional residential options. One afternoon, when riding their bikes near Old North Knoxville, a “streetcar neighborhood” where trolleys once shuttled working-class Knoxvillians the mile or so to and from downtown, Stuth and Shelton spotted a two-family house that appealed to them. Built between 1911 and 1917, the quirky duplex had a generous front porch, decades of peeling paint, overscaled wood ornamentation, and a quarter-acre lot. They bought it for $120,000 and soon moved into one side and had tenants in the other.

While researching the property, Stuth and Shelton learned that there were once three houses on the lot, all nearly identical in style, size, and vintage. The two bracketing the existing house had been condemned and razed decades earlier. The couple began envisioning modernist incarnations of the long-gone structures, built on roughly the same footprints of the old ones: a single-family house for themselves to the west and another two-unit house to the east.

Soon after they started working on the designs, the hoop-jumping began. In the time since the construction of the original houses, the site had been zoned for suburban development, stipulating one house per lot. Local regulators, wary of increasing neighborhood density, didn’t embrace the idea of building the houses back. But after five public meetings, the couple managed to convince skeptics that their design was simply reestablishing a traditional role for the historic neighborhood, which had long offered dense housing close to downtown. Details in the plans took cues from the old houses, paying homage to their Southern past—generous overhangs, south-facing porches, and natural ventilation—while remaining open internally, unlike those of their compartmentalized predecessors. “The shells were designed to be sympathetic with the older house,” Shelton explains. “But inside, they play by different rules.”

The couple eventually got the go-ahead, thanks to growing support for the project that was influenced, perhaps, by nostalgia for what had once been there. “The memory of the houses haunted this site,” Shelton says. “People in Knoxville knew they were here. It was a living memory.”

They aptly dubbed the project the Ghost Houses—and with their pale exteriors and light-filled interiors, the structures do feel spectral.

The couple started building the new duplex first but immediately ran into trouble: It turned out the land on the eastern half of the lot was unstable. Shoring up the soil, using filter fabric, compacted fill, and flowable fill (a kind of low-viscosity concrete), meant short-term compromises. “We were $50,000 behind before we even started,” Shelton says. “All the interior finishes for our own house went into that hole.”

To keep costs under control they kept finishes in the new duplex simple and durable, opting for polished-concrete floors, clear-sealed plywood walls, and simple white drywall. The main cost savings came from maximizing the rentable space, carving out two two-bedroom apartments in a 1,770-square-foot footprint. They created a sense of volume by siting bedrooms on split levels and incorporating sliding walls that allow tenants to expand and contract their living spaces as needed.

Once their new tenants moved in, Shelton and Stuth turned to their own house—and to their credit cards. They didn’t need much space, but they wanted to keep the general outline consistent with the other two houses. To that end, almost half of the ground floor is dedicated to a generous outdoor room while the other half comprises the living space.

In both new buildings, the couple splurged on systems that would result in savings later—for example, advanced framing, two layers of insulation, and an instantaneous water heater that creates hot water on demand. The interior finishes will come in time. The stairs leading to the next floor are temporarily constructed of two-by-fours. A galvanized-metal cattle trough stands in for the Japanese-style ofuro tub they hope to install one day. Handwritten instructions to the builders are jotted on the interior walls. The front porch remains unenclosed.

Their own house may be evolving, but the four units Stuth and Shelton rent are fully leased, mostly to architecture students. Eventually they’ll replenish their bank accounts and finish their punch list. But in the meantime, it seems fitting that at least one of the Ghost Houses sits in a kind of limbo, like its spirit-world namesake.