Prefab / Modular ADU in California

Ataman Studio is a trusted ADU contractor in Los Angeles, serving all of California. Full-service design, permitting, and construction for detached ADUs, garage conversions, and in-law units, with compliance to local zoning and state regulations.

California Tiny House, based in Fresno, CA, builds custom tiny homes, ADUs, granny flats & commercial structures. Offering in-stock models, DIY programs & financing via 21st Mortgage for residential & commercial clients.

Prefab vs. stick-built ADUs explained. Homeplex offers the Clever ADU, an HCD-certified modular unit built all-electric in a factory, saving 5–6 months vs. traditional construction. Costs vary based on site conditions.

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.

Bay Area Home Remodelers builds ADUs in Daly City, San Francisco & San Jose. Services include garage conversions, granny flats, JADUs & detached units. Full project support from permits to completion.

ADU Custom Home Source, based in Riverside, CA, specializes in custom manufactured homes and ADUs. Serving Southern California, they handle design, permitting, financing, and installation, offering granny flats, casitas, and detached ADUs.

Cousin Gary Homes – Sacramento specializes in ADU & JADU construction, offering 80+ floor plans from 546–2,536 sq. ft. Benefits include added property value, rental income & flexible living. California's 2023 ADU laws make building easier than ever.

EHD Builders offers ADU construction services in Los Angeles, CA, including garage conversions, detached units & additions. Costs range from $150K–$350K+. Services cover permits, framing, plumbing, electrical & more.

Humbuildt Homes is an Arcata, CA general contractor specializing in sustainable prefabricated homes for Humboldt County. They offer affordable, energy-efficient housing guided by integrity, innovation, and quality, with a streamlined build process from consultation to completion.

Type Five is a Berkeley, CA-based ADU builder offering custom backyard cottages, granny flats & in-law suites. They combine modular design, transparent pricing & streamlined construction for stress-free, high-quality detached ADUs built to last.

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.

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.

ADU Geeks is a full-service ADU contractor offering planning, design, permitting, and build support. They also provide a $150 online ADU Development Masterclass covering feasibility, financing, and construction, ideal for California homeowners and investors.

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.

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.