Ms. Childs added, “Throughout the project, we had to keep telling the workers: ‘No, don’t make it so perfect. An old warehouse shouldn’t be perfect.’ ”

But it can be practical. A 2,000-square-foot solar array on the roof allows the couple to receive money back from the electrical company every month despite the luxury of radiant-heat floors. Ms. Childs keeps planters brimming with chives, lemon thyme and sage in the wraparound garden, which also manages rainwater runoff.

Downstairs, an existing guest apartment was supplemented with a model-train room, bathroom, weight room and two-car garage, where they park their Mini. The other bay is used as an indoor dog run on rainy days.

When the project was completed last year, at about $310 a square foot, the couple invited the neighborhood over. A local blues band played for some 175 people, and food carts were parked outside.

There’s only one aspect of Portland the newcomers haven’t been able to embrace. “I picked out the perfect Dutch bicycle,” Ms. Childs said. “But I realized I’m terrified to ride in a city. So my bike sits in the garage and looks pretty as hell.”