Ioana Chinan and Kenji Hasegawa 長谷川兼司 collaborate through StudioOna and Hasegawa Construction to bring together residential design, permitting support, and hands on construction expertise in the Bay Area. Their work bridges design and craft, joining thoughtful spatial planning with the precision and integrity of skilled building.
Ioana Chinan, founder of StudioOna and principal designer, brings over 15 years of experience in residential design, interiors, permitting coordination, and project development across the U.S. and Europe. She holds a Ph.D. and a Master of Science in Architecture from the University of California, Berkeley, where she also taught architectural design and theory. Her research and teaching continue to shape a thoughtful, context driven approach to design, one that values environment, material, and lived experience as much as form.
Through StudioOna, Ioana leads the design and permitting process, guiding residential projects through planning, zoning, and building department approvals across multiple Bay Area municipalities. Her role connects creative vision with technical coordination, helping each project move from concept toward construction with clarity and care.
Kenji Hasegawa, founder of Hasegawa Construction and a California licensed general contractor, brings a deep background in craftsmanship, carpentry, furniture making, metal work, and construction coordination. Born in Takasago, near Kobe, Japan, Kenji’s work is rooted in respect for natural materials, handcraft, and the quiet discipline of making.
Construction services are provided by Hasegawa Construction under separate construction agreements with the owner. Kenji’s responsibilities include construction supervision, subcontractor coordination, material procurement oversight, and quality control. His work reflects precision, integrity, and care at every built detail.
Together, Ioana and Kenji share a collaborative approach grounded in professional integrity, craftsmanship, honesty, and a commitment to excellence. Their work brings together two complementary perspectives: the discipline of design and the lived wisdom of building. Each project becomes a conversation between drawing and making, concept and craft, resulting in spaces that are clear, balanced, and deeply human.
StudioOna provides residential design, permitting support, interior design, and owner coordination services. Construction services are provided separately by Hasegawa Construction, a California licensed general contractor, under a separate agreement with the owner. StudioOna and Hasegawa Construction are separate businesses unless otherwise stated in a written agreement.
VALUES
Professional Integrity
We act with transparency and accountability at every stage. Our clients trust that our decisions reflect their goals and the enduring quality of the work.
Craftsmanship
We value precision and the art of making. Each drawing, connection, and finish reflects our commitment to excellence and respect for materials.
Honesty in Design and Construction
We believe that beauty comes from truth in materials, in methods, and in communication. We advocate for clear intentions, honest budgets, and well built work.
Commitment to Excellence
Excellent work is thoughtful, durable, and responsive. Each project is a collaborative effort toward a lasting contribution, one that stands the test of time in both function and spirit.
We design with honesty, build with integrity and craft with purpose
CLIENT REVIEWS
Sharon W.
When you are spending thousands of dollars on house renovation projects, you want to get it right. So, my husband and I decided to hire a designer to help us pick the best materials for our projects. Ioana from StudioOna&Hasegawa was fully invested in our projects from the beginning. She was professional, knowledgeable and personable. We replaced our deck, our living room furniture and all the floors in our house. Ioana listened to our wishes and offered suggestions. She was patient and kind. She went to stores and showrooms with us to help choose our oak floors. She also went to the furniture store to choose our new family room furniture. She sent us a sketch of a design layout for our new deck with pictures of the many ways we could decorate the space. We used those ideas for décor and lighting. Ioana helped us make our home more comfortable and inviting. We are enjoying the re-designed spaces with family and friends. She exceeded our expectations, and we highly recommend her.
Jennifer D.
Ioana is an absolute joy to work with. She’s an extraordinarily knowledgable and gifted designer. Her intelligence and creative prowess made the process of designing our basement renovation a total dream. We trusted her insight and guidance, as she holds herself to an incredibly high standard. We feel so lucky to have found her and would work with her again in a heartbeat!
Martina F. 
Working with StudioOna&Hasegawa on our window replacement and exterior upgrade was a pleasure. They brought a strong sense of design and building performance, helping us reimagine the façade for better curb appeal and improved energy efficiency. Their guidance through the permitting process was seamless—they coordinated with the city and handled all technical documentation with precision. Their responsiveness and ability to clarify complex decisions stood out, from selecting high-performance windows to addressing waterproofing and long-term durability. The result is a home that looks and performs better, fully up to today’s energy standards. We’re grateful for their thoughtful, expert coordination and highly recommend StudioOna&Hasegawa for anyone seeking a team that combines design vision with practical know-how
↑Back to Top