The San Anselmo Residence is a project designed for an architect which involved an existing 1950s house up on a tree-filled hilltop in Marin County. Pfau Long Architecture, the residential studio of Perkins&Will, kept the original structure but updated it and expanded it to 2800 square feet while transforming it into an eco-friendly home. A new wing was added to the existing footprint to add two bedrooms and a new kitchen and family room.