Detached ADU near San Mateo, CA

Regency Construction & Remodeling BA is a San Francisco ADU contractor offering new builds, space conversions, and prefab ADU solutions. They handle design to completion, manage permits, and ensure compliance with local zoning laws.

ADBC Architecture completed an 800 SF detached ADU in East Bay, CA in 2025, designed for multigenerational living. Built with thermally modified wood and steel, the backyard cottage features high ceilings and large windows for a spacious feel.

Anura Design specializes in ADU design, offering styles from modern farmhouse and contemporary steel to Mediterranean stucco. Their interiors feature open-concept layouts, natural wood tones, and refined finishes tailored to compact, functional living spaces.

ExpandADU is a California-based prefab ADU builder offering full-service accessory dwelling unit construction, including consultation, design, planning, and build. Serving the Bay Area and beyond, they specialize in detached ADUs, granny flats, and JADUs.

BuildZig ADU Services is a Bay Area ADU contractor specializing in design, permitting, and construction. They handle garage conversions, detached ADUs, basement/attic conversions, and more, offering transparent pricing throughout.

Custom Home is a Bay Area ADU contractor (CSLB #986048) with 160+ projects since 2005. They build detached, attached, junior ADUs & garage conversions across South Bay & Peninsula, with costs from $120K–$500K+.

Manzanita Design Build is an East Bay ADU contractor specializing in accessory dwelling units. Serving Berkeley, Oakland, Alameda & more. New ADU construction starts ~$300K, 5–8 month build time. Licensed (#1034108) & insured.

Inspired ADUs is an architect-led ADU design firm serving the Bay Area and Southern California. With 20+ years of experience and 250+ ADUs permitted, they offer custom, panelized, and modular ADU solutions, plus interior design and SB9 lot split services.

Nestadu is a full-service ADU builder offering custom site-built and prefab accessory dwelling units. Prefab models range from $115K–$317K. Custom builds start at $400/sq ft. Financing options include HELOCs, construction loans, and CA grants.

ADU Home Addition is a leading Bay Area ADU contractor with 12+ years of experience. They specialize in custom ADU construction, in-law suites, garage conversions, home additions, and rental-optimized ADUs, handling design, permits, and full construction.

Aboveboard Construction Inc. serves Santa Cruz County & Los Gatos with 20+ years in residential construction. Services include new homes, ADUs, remodels, additions, kitchens, bathrooms, decking, fencing & repairs.

Geico Builders offers ADU services including detached ADUs, attached ADUs, Junior ADUs, garage conversions, and home additions. Ideal for rental income, family housing, or maximizing space on your existing property.