Prefab / Modular ADU near Mission Viejo, CA

USModular Inc. is a Temecula, CA ADU builder specializing in modular, prefabricated construction. Units are up to 90% factory-built, completed in ~120 days, and comply with IRC and local codes. Services include feasibility studies, design, engineering, permitting, and installation.

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.

Revival Homes is a California ADU project manager handling planning, financing, design, permitting, and construction. They build detached ADUs, garage conversions, JADUs, and more, with costs ranging from $100K to $300K.

North County ADU Construction is a local ADU contractor serving north San Diego County. They specialize in garage conversions, JADUs, detached ADUs, and prefab installs. With 500+ builds and a 96% satisfaction rate, they handle design, permitting, and construction.

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.

Full Circle Builders offers custom ADU construction in Riverside County & the Inland Empire. Detached ADUs start at $185,000 (590 sq ft, 1BD/1BA). Container homes also available. Turn-key builds, permitting assistance included.

The Springfield by Superior ADUs is a 2-bed, 2-bath detached ADU with open-concept living, vaulted ceilings, mini-split HVAC, kitchen island, ample storage, and optional ethanol fireplace—ideal as a granny flat or in-law suite.

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.

Sequoia Homes & Backyard Bungalows offer affordable ADU builder services in Carlsbad, CA. From granny flats to in-law suites, they handle design, permits, financing & installation. Projects completed in as little as 8 weeks.

Paramount Manufactured Sales in Riverside offers Skyline Homes-built ADUs for Southern California homeowners in LA, Orange, Riverside, San Bernardino & San Diego Counties. Models range from 479–849 sq ft. California law now allows detached ADUs up to 1,200 sq ft.

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.

Cali ADU is a top Los Angeles ADU builder offering custom and pre-designed accessory dwelling units, garage conversions, and granny flats. Fixed pricing, fast permitting, and expert project management ensure stress-free builds from design to move-in.

US Modular Inc. is a trusted ADU builder in Riverside County, CA, with 35+ years of experience. They offer prefab ADUs, garage conversions & casitas starting at $150,000, completed in 6–9 months.

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.

ADUs are secondary units built on existing lots. ORR Construction builds detached ADUs, garage conversions, JADUs & in-law suites in California. Costs range $50–$300/sq ft. California laws like SB 897 simplify the permitting process.