Prefab / Modular ADU near Irvine, 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.

BSPK Design is a Venice, CA residential studio founded by Chris Faulhammer & Roman Reiterer, with 50+ years combined experience. Services include custom homes, fire rebuilds & prefab NextGen Building. Multiple Houzz Best of Design award winners.

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.

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.

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.

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.

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.

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.

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.

MyADU4Less is a Southern California ADU builder specializing in prefabricated accessory dwelling units. Offering models from 160–1,200 sq ft, they handle design, permitting, and construction. CalHFA grants up to $40,000 may apply.

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.

Crest Backyard Homes is San Diego's trusted ADU builder, specializing in prefab, detached ADUs, granny flats & garage conversions. Their all-inclusive team guides homeowners from design to completion, ensuring code-compliant, high-quality accessory dwelling units.

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.

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.