The clients are a couple of environmental scientists who, along with their two sons, relocated from the Oakland Hills to the warmer climate of Orinda. Their commitment to sustainability, including a request for net-zero energy performance annually, was evident in their thinking throughout the design process. A three-bedroom program began as a remodel of a 1954 ranch house at the foot of a hill next to a seasonal creek. After finding the existing structure and soils to be unsuitable, the direction settled on reusing the existing footprint under the shade of a Valley Oak that had grown up close to the original house. The surviving portion of the original house is the fireplace which was wrapped in concrete and utilized for structural support. This made additional grading unnecessary and allowed the new house to maintain the same intimate relation to the old oak.