“When we wanted, as so many Texans do, a place to get away from the heat, we decided to take a couple of weeks and drive through all the Colorado towns,” Ms. Eyles said. Telluride (population 2,426) charmed them instantly because, unlike Vail, which was incorporated in 1966, it’s “not just a ski town.”

“You feel the sense of history,” she said.

The couple built a 3,000-square-foot house in 2005. Finding it too cramped for their many visitors, they purchased an adjacent plot that came with a special advantage: Building plans had already been approved by the town’s Historic and Architectural Review Commission, which can be a complicated process.

But building in a community that values its architectural heritage poses challenges beyond the approval process. It is also about designing a home that blends in with the older structures on the outside, while meeting the needs of the owner for something contemporary and comfortable on the inside.

That was the hurdle for Ms. Eyles.

“The architectural board is filled with a variety of people: architects, designers, just local bigwigs, and they were all sitting there,” Ms. Eyles said of a meeting she attended. “Somebody was trying to get this covering for their hot tub approved and this committee spent — I’m not kidding — 45 minutes or an hour having a discussion about what to call this structure. Was it a pergola? A pagoda?” Typically, the total approval process takes a minimum of nine to 12 months, said Ms. Eyles’s contractor, Dave Gerber of Gerber Construction, though Ms. Wensel said getting the go-ahead from the architectural board takes just two months.