Architecture and Urban Design

CO- designs places at a broad range of scales and types. We are a design-led studio that cares about sustainable implementation in the built environment. When conceiving buildings or masterplans, we always consider design in its context and the context through its architecture, landscape, and culture.

Our mission is to work with our clients, both organizations and individuals, to dream up and deliver projects that perform beyond the initial brief. Whether we are working on interior renovations, feasibility studies, standalone buildings, or large-scale masterplans, CO- approaches every project with a commitment to design excellence and creativity.

CO- is fully licensed to provide architectural services in the United States and New Zealand.


Real Estate Development

CO- is a comprehensive real estate development services firm. With a proven track record of navigating complex affordable development processes, our primary mission is to create quality and accessible housing, particularly in some of the most unaffordable markets in the country.

We are committed to delivering exceptional products by managing budgets, securing financing, coordinating the permitting and approval process, overseeing bidding and construction, and engaging with government and local community organizations. Our expertise in acquisitions, land transactions, new construction and rehabilitation projects, obtaining planning approvals and building permits, managing design and engineering consultants, securing financing from private and public lenders, closing construction and permanent financing, negotiating construction contracts, overseeing construction, and managing the lease-up and marketing process allow us to engage in the development of various project types and sizes.

We work closely with our partners and clients to turn their vision into reality. Through development, CO- is passionate about making a positive impact in the communities we serve.


Our collective process draws on our design experience and pedigree to imagine and iterate and on our development and project management expertise to qualify those design options for implementation.

As a single studio that engages in both design and real estate development, CO- balances concern for the character of our design investigation with handling the critical externalities that enable our ideas to become reality. Making housing, particularly quality affordable housing, is CO-‘s immediate and long-term focus.

CO- is a registered Minority-Owned San Francisco Local Business Enterprise (LBE) and a Micro Local Business Enterprise.


  • Weijia Song, RA

    Weijia Song, RA

    Co-Founder and Principal

    Weijia Song is an architect and an affordable housing developer. Hailing from Auckland, New Zealand, Song received her Bachelor of Architecture from Rice University and Master of Science in Real Estate Development from the Massachusetts Institute of Technology where she was a Samuel Tak Lee Real Estate Entrepreneurship Fellow and the recipient of the MIT Center for Real Estate Thesis Excellence Award.


    Previously, Song was an Associate Architect at SHoP Architects in New York, where she helped design and manage a series of large-scale public infrastructure projects and private developments including the East River Waterfront Esplanade. Additionally, Song has spent time at Investbridge Capital in Dubai, where she has experience in investment analysis and fund structuring. She has also worked on urban design and architectural projects with Ricardo Bofill Taller de Arquitectura and WW Architects. She is a Registered Architect in New Zealand and California.

  • Alex Yuen, RA

    Alex Yuen, RA

    Co-Founder and Principal

    Alex Yuen is an architect and urban designer. Hailing from Hong Kong and San Francisco, Yuen received a Bachelor of Architecture from Rice University and a Master of Architecture in Urban Design, with Distinction, from the Harvard University Graduate School of Design. His individual design work and involvement in larger urban research projects have been published and exhibited globally. Yuen is the recipient of numerous awards, including the Odebrecht Award for Sustainable Development, the William Ward Watkin Fellowship from the Rice School of Architecture, and the Award for Excellence in Urban Design and the Urban Design Thesis Award from the GSD.


    Yuen is currently a faculty member at the Harvard University Graduate School of Design and has previously taught at the California College of Arts and the University of Virginia while also having lectured on architecture and urbanism and serving on juries at institutions around the world. Prior to CO-, he worked at a number of Architectural and Urban Design firms around the US and Asia, including Diller Scofidio + Renfro and the Office for Metropolitan Architecture (OMA). Yuen is a registered architect in California and a LEED Green Associate.

  • Austin Sun

    Design and Development Associate

    Austin Sun is a designer and photographer. He studied geology at Colgate University and continues to expand his interest of the natural and built environment through his pursuit of a dual degree in both a Master in Architecture and Master of Landscape Architecture at the Harvard Graduate School of Design. He has previously worked at a range of design firms, including MASS Design Group, The LADG, and Studio Sean Canty. In his free time, Austin is an avid photographer, skier, hiker, biker, and generally enjoys spending time in nature.