599 Castro is a 110,000 square foot, four-story mixed-use project with three levels of below grade parking located in downtown Mountain View, California. The project includes Class A office, retail, and residential with frontages on three streets including Mountain View's main downtown thoroughfare, Castro Street. The project shares the site with 100-year-old St. Joseph's Catholic Church. The church's traditional Mediterranean architectural style influenced the architecture of 599 Castro.

The developer and owner of the project chose to make 599 Castro their new headquarters and occupy the fourth floor of the building. In choosing the project as their corporate headquarters, the Owner wanted to develop a timeless building that would evoke the quality of design and development for which the organization is known. Early in the design process the team decided to use GFRC as the primary facade material for its high quality, lasting durability and the architectural look and feel it created. Once the GFRC was selected as part of the design, the challenges were to incorporate the high level of Mediterranean details needed for a successful project.

In addition to the detailing of the GFRC panels, the team developed details that incorporated custom carved limestone pieces into the GFRC. The combination of the details, materials, and careful changes in color and finish provided the project with the high-quality permanent feel the design required. In addition, the location of the project on an urban site in downtown Mountain View with zero lot lines along the street frontages required an efficient skin system for installation in the confined space. The panelized GFRC system helped with the restrictions of the site and helped with the construction schedule.