If you are an architect with a minimalist approach, it may be hard to find clients equally obsessed with abstraction and austerity in materials and details. Yet Terence Riley, principal of the New York– and Miami–based firm K/R, recently designed a small one-story, one-bedroom cottage in Coconut Grove for someone who might be more minimally minded than he is. “I could live in a house and be completely satisfied if it were empty,” says the owner, Sonya DeLong, an American who spends part of the year in Switzerland, her husband’s native country. “I deliberately own very little.” Which is a good thing. Her new rectangular dwelling is 80 feet long and 20 feet wide. The attenuated 1,500-square-foot bar-like building sits within a 6,800-square-foot property roughly the shape of a triangle: at the narrow, western end is the entrance from the street, which leads into the living and dining area. At the opposite end is the bedroom, opening onto a verdant garden.

The elegantly proportioned plan allows the elongated south-facing wall of glass to open out to a perimeter walkway sheltered by the roof’s 6-foot cantilever. On the other side of the covered walk, a linear pool echoes the house’s proportions at a smaller scale. Demarcating the edge of the narrow path is a pebble-filled channel that captures rainwater from the canopy overhead.

To give a sleek, pristine finish to the planar surface of the concrete block structure, Riley coated it with a smooth, high-grade stucco. Inside, the floor of Douglas fir planks, 17 1/2 inches wide, adds warmth to the almost monastic ambience. Contrasting with these precise architectural moves is the luxuriant planting outside, created by landscape consultants Naturalficial with a voluptuousness that softens the residence’s spartan tone.

“The integration of outdoor and indoor spaces and the lack of clutter keep the spaces from feeling cramped,” says Riley. “And not having stuff makes Sonya and her husband feel comfortable.” While Riley and his partner, John Keenen, are engaged in nonresidential projects such as the new Sarasota Art Museum and a mixed-use building in the Design District in Miami, their completed houses already demonstrate an impressive investigation of plan, line, and surface. Serenity is in the details.