Cade Hayes admits he was nervous when he started work on the Tucson Mountain Retreat, a 3,650-square-foot house on the edge of Saguaro National Park. Having grown up in New Mexico, he had developed a love of the desert. 'It was our first project and we didn't want to scar the land,' says Hayes, who runs DUST, a Tucson-based design-build firm, along with Jesus Robles. Both Hayes and Robles studied architecture at Texas Tech, and Hayes had worked for architect Rick Joy for five years, so they had the skills for the job. But their respect for the area's rugged yet fragile terrain kept them humble in the face of building on it.

Luckily, their clients'David and Karen Francis, who live in San Diego, and their daughter Nina, who is at college studying music'shared their kinship with the land. David Francis grew up in Tucson and wanted a house there for weekends and vacations, a place where he could reconnect with the desert and indulge his love of music. He had visited a friend who owns a rammed-earth house designed by Joy and told him, 'You'll have to call 911 to get me out of here.' But instead of commandeering his friend's residence, he bought a 6'-acre site nearby in the Tucson Mountains and built his own house. 'I wanted a low-maintenance place, since we would be there only part time,' says Francis, explaining why he picked rammed earth. 'And it just seems like the right material for this area.'