“It really is like being at a luxury resort,” says designer Jill Norman of the private wellness center she and Cameron Shepherd created for their clients in Rancho Santa Fe, California. Indeed, the designers drew inspiration from Costa Rican eco-resorts to transform a dated outbuilding (once home to a lonely indoor pool), which sits just a short walk from the family’s main residence. Now, the inviting destination boasts myriad uses: There are hot and cold plunge pools, a cedar sauna lined with pink Himalayan salt, a powder room and meditation deck, to name a few. And while Norman and Shepherd chose practical materials befitting a spa—like plaster walls that are naturally antimicrobial and easy-to-scrub porcelain tile surrounding the plunge pools—what sets the design apart is its warm detailing. See the quiet art pieces (an abstract painting, a woven wall hanging), vintage-style runner, and thoughtful variations of woods across the ceiling, walls and doors. “So many spas are tranquil but also homogenous—all tile, all plaster—while our favorite rooms are layered and collected,” explains Shepherd. “We wanted these spaces to have focus, while also feeling personal and elevated.”