Accessory dwelling unit builders — San Mateo, CA
Last updated: September 24, 2026
What affects the price
Building an ADU involves several moving parts that shape your total budget. The biggest factor is whether you choose a prefabricated unit or a custom build on-site. Site preparation is also significant; if your land requires extensive grading, utility trenching, or foundation work, costs will climb. Your choice of finishes—like kitchen cabinetry, flooring, and siding materials—also shifts the bottom line. We help you navigate these variables to find a setup that fits your property. Exact pricing confirmed free on the call.
About this service
These are specialized contractors who focus specifically on the design and assembly of secondary housing units. Unlike general contractors who take on all home renovations, these specialists understand the unique constraints of building in backyards or converting existing structures. You need them when you want someone who manages the entire process—including permits and site management—specifically to ensure your ADU is built efficiently, correctly, and according to the specific regulations governing secondary structures on residential lots.
Frequently asked in San Mateo
How do I find an accessory dwelling unit contractor in San Mateo?
What is involved in accessory dwelling unit construction in San Mateo?
What are accessory dwelling units (ADUs) for in San Mateo?
Accessory dwelling units in San Mateo provide flexible housing solutions. They can generate rental income, house family members, or serve as a home office. ADUs increase property utility and value in San Mateo's competitive market. Understand your ADU options by calling us.
What are the accessory dwelling unit financing options in San Mateo?
Accessory dwelling unit financing in San Mateo often involves home equity loans or construction financing. We provide detailed quotes for your ADU project, which helps in securing funds. Our clarity on costs supports your financial planning for San Mateo properties. Call for an estimate.
Are there affordable ADUs available in San Mateo?
What are accessory dwelling unit companies in San Mateo?
What is an accessory dwelling unit and its purpose in San Mateo?
An accessory dwelling unit in San Mateo is a secondary housing unit on an existing lot. Its purpose is to offer additional living space for family or renters. ADUs contribute to housing diversity and affordability in San Mateo. Learn more about ADUs by calling us.
Also serving nearby: Hayward · Daly City · Oakland · Sunnyvale · Fremont
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of San Mateo — population 101,327; about 8,350 residents per square mile across 12.1 sq mi. ZIP codes covered include 94401, 94402, 94403, 94404, 94497.
Neighborhoods served in San Mateo: Aragon, Bay Meadows, Downtown San Mateo, Shoreview, Edgewater — and every surrounding area.
Areas we serve
Browse by state, then city.
California (4)
All of California · Rialto · San Buenaventura (Ventura) · San Mateo · Vacaville