Prefab / Modular ADU in California

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 ... read more

Harmony Design & Build specializes in ADU construction in San Diego, CA. Services include detached ADUs, garage conversions, attached units & custom designs. Ideal for rental income, in-law suites & added property value.

Backyard Unlimited, founded 2009 in Rocklin, CA, specializes in Amish-crafted sheds, gazebos, pergolas, and ADUs for Greater Sacramento homeowners. They handle full ADU design, permitting, and installation in-house, with no subcontractors.

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.

Level Up Contractor is an ADU builder in Los Angeles offering garage conversions, detached ADUs, and JADUs. Services include full permitting, design-build, and LADBS coordination. Costs range from $100K to $450K depending on project type.

prefabADU is a Bay Area ADU builder with 16+ years of experience offering affordable kits and plans from under $45K. With 12 state-approved plans valid across California, they simplify permits, design, and installation for homeowners.

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.... read more

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,... read more

Elite Construction builds ADUs in Santa Cruz County, offering detached units, garage conversions & addition ADUs. Projects range 250–1,200 sq ft, cost $115K–$450K, and take 6–9 months. Free estimates available.

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 wi... read more

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.

Cousin Gary Homes, serving Chico since 1972, offers a wide range of ADU models—from 439 to 1,177 sq ft—including granny flats and backyard cottages. Visit their showroom at 13468 Highway 99 North to explore options.

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.

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, enginee... read more

Building a granny flat (ADU) in San Diego can boost property value and ease housing needs. Detached ADUs up to 1,200 sq ft start at $250/sq ft. Fee waivers may save homeowners $14,000+. Rules apply regarding zoning, lot use, and size limits.