“Abacus pays great attention to detail. They provide the level of detail and service that you get from the big companies, but with fewer layers of management and less hoops to jump through. You get to work directly with the owner – and Chas always wants to do a great project. For him, the architecture matters, and he’s very willing to work with us to make the end product right.”

Ted Bonneau, architect
OXB Studio, Mill Valley


“The greatest strength of Chas, his ability to listen, contributes to all aspects of working with Abacus. He is comfortable with compromise and always offers multiple solutions. The team of subcontractors and suppliers are highly knowledgeable about their craft and are always respectful and mindful of the client. The idea of reaching for excellence informs all decisions with Abacus. I have thoroughly enjoyed our working relationship and highly recommend both Chas and Abacus.”

Laurie Ghielmetti, interior designer
Laurie Ghielmetti Interiors, San Francisco


“As a structural engineer, I work with a lot of general contractors with varying skillsets. Abacus is at the top of my list because of their unusual understanding of engineering requirements and their creativity in helping me achieve them. In addition, they have great craftsmanship, professionalism, integrity, and tenacity. They don’t shy away from challenges, they make the difficult look easy, and they do it with grace. And they are very nice people and a pleasure to work with.”

Ryan Billante, project manager
Morris Engineering, Structural Engineers, San Carlos