Project Size: 3,230 square feet

Program: The client, a businessman with a young family, wanted to experiment with unusual construction methods for his new house on a steep hill overlooking the sea and mountains outside Barcelona. He had three requests—large windows to take advantage of views, privacy from the neighbors, and the use of a new concrete technology that, if successful, could be marketed and used in future projects. The businessman commissioned Cadaval & Solà-Morales because of the firm's past work with concrete for the TDA House in Mexico (2006).

Solution: The architects designed an X-shaped, two-story house on a relatively flat step in the hillside and sprayed high-density concrete at high pressure to single-sided formwork, a technique usually used for tunnels and bridges, not residential work. Glazed portions of the structure were angled to allow privacy from the neighbors and to take advantage of views of the landscape.

The family parks its cars and enters the house at the upper level—with a master suite and studio—and descends to the lower level for a double-height living area, three bedrooms, and a combined kitchen and dining area with a 20-foot-long marble table designed by the architects. A rooftop terrace and balcony overlook a polygonal pool, farther down the hillside, which fits between the arms of the X-shaped plan like a piece of a puzzle.