Founded in 2006 by Marc Ojanen and Shen-I Chiou, OCA is a California-licensed, LEED-accredited firm with over four decades of collective experience in residential, commercial, civic, cultural, and educational projects across the United States, Europe, and Asia.

We offer a comprehensive range of services for high-end residential projects of all types—including new builds, renovations, interior remodels, additions, and ADUs—specializing in revitalizing and modernizing historic Victorian-era single and multi-family homes in San Francisco, re=envisioning early Bay Area suburban ranch-style tract homes, and sensitively updating and future-proofing classic mid-century modern homes. Our expertise also extends to commercial tenant improvements, additions, adaptive reuse, historic preservation, interior architecture, furniture, and graphic design.

With decades of experience throughout the Bay Area, we are adept at solving the unique challenges of problematic building sites and existing buildings, and navigating complex approvals processes.

Our design philosophy centers on clarity, simplicity, and a deep respect for both people and the environment. We synthesize functional, aesthetic, economic, and sustainable criteria to create uplifting, earth-friendly environments tailored to our clients’ needs.

Collaboration is key: we work closely with clients, consultants, and builders to ensure the highest quality design and seamless project delivery. As members of the AIA (American Institute of Architects), USGBC (U.S. Green Building Council), and NCARB (National Council or Architectural Registration Boards), we are committed to professional excellence and sustainable building practices.