Prefab / Modular ADU in California

Ultra-Unit Architectural Studio, based in Long Beach, CA, offers architecture and construction services for ADUs, residential, multifamily, and commercial projects. Led by Cameron Crockett AIA, LEED, with 25+ years experience. Free initial consultations available.

Bay Builders & Remodeling specializes in custom ADU construction across Santa Clara, San Mateo, and East Bay. Services include attached, detached, garage conversions, and JADUs, helping homeowners add rental income, family housing, or workspace.

CCPP helps homeowners plan & permit ADUs in San Luis Obispo County. Options include custom, stock plan, or manufactured units. Permitting takes 4–12 months, with costs ranging from $40K–$70K depending on ADU type.

West Coast ADU is a California-based ADU builder offering prefab & manufactured accessory dwelling units. They help homeowners add rental income, house family members & boost property value with streamlined permitting & construction.

Eagle ADU is a licensed ADU builder in Northern California offering three signature models: Eagle Studio ($180K–$220K), Eagle One ($230K–$280K), and Eagle Two ($310K–$360K), with rental income potential up to $4,000/month.

Nestadu is a full-service ADU builder offering custom site-built and prefab ADUs. Site-built units start at $400/sqft; prefab models from $115K. They handle design, permitting, and construction, plus financing guidance including HELOCs and grants.

LiveLarge Home is a California prefab ADU builder offering full-service solutions from permits to final inspection. Build times start at 4–6 weeks, with fixed pricing from $412/sq. ft. Models range from studios to 2-bed/2-bath units with premium finishes.

Addition Builders LA is a full-service ADU contractor in Los Angeles offering custom ADUs, prefab units, and garage conversions. Licensed, bonded, and insured, they manage design to construction, completing projects in as little as nine months with transparent pricing.

Eco Scale Construction builds ADUs in Sunnyvale, Los Altos & Palo Alto, CA. Services include detached ADUs, garage conversions & JADUs. Costs range from $80K–$400K+. Fully compliant with California ADU regulations.

ADU Los Angeles (ADLA) is a specialized ADU contractor serving LA County. They offer consulting, custom design, construction, garage conversions, basement ADUs, attached and detached units, helping homeowners maximize property value.

Proteus Homes is a custom home and ADU builder with 30+ years of experience in the Southwest US. They offer full-service ADU construction, including design, permitting, and panelized off-site fabrication, with move-in-ready homes in under three months.

ADU Custom Homes is a licensed California ADU contractor with 35+ years of experience serving LA, Orange & Riverside counties. They specialize in detached ADUs, garage conversions & additions, managing projects from permits to Certificate of Occupancy.

Los Angeles Advanced ADU Builders offers full-service ADU construction across LA, including garage conversions, detached units, JADUs & prefab ADUs. With 20+ years experience & 500+ builds, they handle design, permits & zoning compliance.

California ADUs (granny flats) add rental income or family housing to existing lots. Detached units up to 1,200 sq ft are allowed. Building costs start at $1,200/sq ft. Hire a specialized ADU contractor in San Diego for permits and zoning compliance.

ADU Design Homes is a full-service ADU design and build firm in Los Angeles and Orange County. They handle detached ADUs, JADUs, garage conversions, permitting, engineering, and construction under one roof.