"I felt it would be a lot of fun to design and build a cast-in-place reinforced concrete house, so I sketched out this little bungalow on the brow of a hill," says Harold Ashton, founder and CEO of The Ashton Company, Tucson, Ariz. He took his drawing to Tucson architect Diana Kuhel Osborne, who developed the design. Nestled in the foothills north of Tucson, the surrounding desert both complements and contrasts with the home. All walls, columns, and the roof are made of reinforced concrete. The exposed-aggregate concrete of the walls is repeated in exterior landscape dividers and retaining walls, and the turquoise-colored overhanging fascia adds a bright note.

The foundations and floor slab are 3000-psi concrete.

The concrete roof slab in the living/dining and bedroom sections of the house tapers from 8 inches thick at the perimeter of the circular plan to 4 inches near the front entrance. In the rectangular garage wing, the roof is a constant 4 inches thick. A built-up roof covers a layer of rigid insulation on top of the concrete slab.