Prefab / Modular ADU near Foothill Ranch, CA

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.

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.

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.

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.

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.

ABODU offers factory-built, fire-resistant ADUs installed in a single day. HCD-approved and AB 462-compliant, their prefab units help wildfire rebuild families return home faster, with Certificates of Occupancy issued before primary dwelling completion.

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.

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.

Ghousetechnologies is a California ADU contractor offering steel frame accessory dwelling units. Models range from 360–1,200 sq ft. Builds are fire, flood, earthquake, and hurricane-resistant, eco-friendly, and completed faster than traditional construction.

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.

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.

A1 ADU Contractor specializes in garage conversions and custom ADU construction throughout Los Angeles and the San Fernando Valley. With over 15 years of experience, our team provides complete design, permitting, and construction services to transform underutilized spaces into beautiful, functional living areas. Whether you're creating a rental unit, guest house, home office, or multi-family dwelling, we deliver high-quality craftsmanship and personalized solutions tailored to your needs.

Avica Construction & Development Inc is a licensed LA-based ADU contractor building detached ADUs, garage conversions, attached ADUs & JADUs across Los Angeles, Orange County & San Bernardino County, managing design, permits & construction.

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.

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.