ADU Contractors in California
Wise Builders
2355 Paragon Drive, San Jose, CA 95131
Wise Builders is a Bay Area ADU contractor with 20+ years of experience in accessory dwelling units, garage conversions, and attached or detached ADU construction across San Jose, Sunnyvale, and Silicon Valley. Free estimates available.
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SE Builders Inc
13006 Philadelphia Street, Whittier, CA 90601
SE Builders Inc completed an ADU project in Fullerton, CA, transforming a structure into a modern living space. Features include updated framing, durable finishes, eco-friendly materials, energy-efficient systems, and low-maintenance landscaping.
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Halsell Builders
2325 Skyway Drive, Santa Maria, CA 93455
As a full-service construction company focused exclusively on ADUs and multifamily housing, we guide you through every step—from initial concept to final walkthrough. Whether you're adding a high-quality ADU to your property or developing affordable housing solutions for your community, we deliver spaces that are functional, personal, and built to last.
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JDB Builders - Riverside
11801 Pierce Street, Riverside, CA 92505
Building an ADU in Riverside takes 8–16 months. JDB Builders guides homeowners through design (1–3 months), permitting (2–4 months), construction (4–8 months), and final inspections (1–2 months) for granny flats, garage conversions, and more.
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Joel & Co. Construction
11693 San Vicente Boulevard, Los Angeles, CA 90049
Joel & Co. Construction, serving Los Angeles since 1983, offers expert residential & commercial construction, including custom homes, kitchen & bathroom remodels, ADUs, room additions, and general contracting across Beverly Hills, Santa Monica & beyond.
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ADU Conversion
Los Angeles, CA
ADU Conversion is a California-based ADU contractor specializing in detached ADUs, garage conversions, Junior ADUs, and attached units. They manage design, permitting, and construction, ensuring compliance with California ADU laws for homeowners seeking rental income or multigenerational housing.
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Motif Architecture
30211 Avenida De Los Banderas #200, Rancho Santa Margarita, CA 92688
Motif Architecture offers ADU, JADU, and garage conversion design services in Orange County, CA. Their five-phase process covers space planning, permitting, and construction. Projects include backyard cottages and garage-to-ADU conversions in Costa Mesa and Irvine.
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1 Degree Construction
13107 Ventura Boulevard, Studio City, CA 91604
1 Degree Construction is a Los Angeles ADU builder & home addition contractor. Services include detached ADUs, garage conversions, second-story additions & in-law suites. Projects range from $30K to $150K+.
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Rosegold Builders, Inc.
358 South Abbott Avenue, Milpitas, CA 95035
Rosegold Builders builds custom ADUs across the Bay Area and Los Angeles, handling permits, zoning, and construction. Services include garage conversions, backyard cottages, and rental units designed to boost property value.
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Dobson Construction Inc.
5021 Blum Road, Martinez, CA 94553
Dobson Construction Inc. is a Bay Area ADU contractor with 16+ years of experience building home additions, detached ADUs, guest suites, and garage conversions. They handle design, permits, and construction for functional, value-adding residential spaces.
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CityPaks
San Francisco, CA 95130
CityPaks is a minority & woman-owned ADU builder in the San Francisco Bay Area specializing in affordable, sustainable backyard cottages & detached ADUs using SIP panels. No crane needed, no sales tax, pre-approved in San Jose.
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Infinity ADU
645 West 15th Street, Long Beach, CA 90813
Infinity ADU is a top ADU contractor in Long Beach, CA, specializing in attached, detached ADUs, granny flats & garage conversions. They handle design, permitting & construction, ensuring full local code compliance for a stress-free build.
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CCS Inc
16906 Burbank Boulevard, Los Angeles, CA 91316
CCS Inc (CSLB #B1047699) is a licensed LA general contractor since 1984 specializing in ADU construction, garage conversions, and room additions. They manage design, permitting, and build, with ADUs generating up to $3,500/month rental income.
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MTR
1984 Enterprise Boulevard, West Sacramento, CA 95691
MTR (Modern Technology Resources Inc.) offers full-service ADU design and construction in Sacramento, CA. Services include custom builds, garage conversions, permit management, and prefab options—helping homeowners add value with functional, affordable accessory dwelling units.
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Bergstrom Construction Inc.
10232 I Avenue, Hesperia, CA 92345
Bergstrom Construction Inc. builds custom ADUs in Apple Valley, Victorville & Hesperia. Serving San Bernardino County, they offer in-law suites, backyard cottages, home offices & garage additions tailored to High Desert homeowners.
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Other cities in California
What you need to know
ADU Contractors in California: Navigating the Golden State's Unique Landscape
California is at the forefront of the Accessory Dwelling Unit (ADU) movement in the United States. With one of the most severe housing shortages in the nation, the state has enacted sweeping legislation to make ADU construction more accessible. Since 2020, California laws such as AB 68, AB 881, and SB 13 have significantly reduced barriers, eliminating minimum lot size requirements, reducing setback rules, and streamlining the permitting process. For homeowners looking to add value to their property or create additional rental income, working with experienced ADU contractors in California has never been more important.
What California ADU Contractors Must Know About State Regulations
Professional ADU contractors operating in California must stay current with a constantly evolving regulatory environment. Under California law, local agencies are required to approve or deny ADU permit applications within 60 days. Additionally, ADUs under 800 square feet cannot be denied solely based on floor area ratio limits. Contractors must also be familiar with owner-occupancy rules, utility connection requirements, and fire safety standards that vary by county and municipality. Cities like Los Angeles, San Diego, and San Jose each have their own local ordinances layered on top of state law, making local expertise a critical asset.
Types of ADUs Built by California Contractors
Experienced California ADU contractors are skilled in building a wide variety of ADU types to suit different property configurations and homeowner needs. The most common types include:
- Detached ADUs: Standalone structures built in the backyard or side yard of a primary residence.
- Attached ADUs: Units that share a wall with the main home, often built as additions.
- Garage Conversions: Transforming existing garages into livable spaces, a popular and cost-effective option.
- Junior ADUs (JADUs): Units up to 500 square feet created within the existing footprint of a home.
How to Choose the Right ADU Contractor in California
Selecting the right contractor is one of the most critical decisions in any ADU project. Homeowners should look for contractors who hold a valid California Contractors State License Board (CSLB) license, ideally a Class B General Building Contractor license. It is also important to verify that the contractor carries proper liability insurance and workers' compensation coverage. Look for professionals with a proven track record of successfully permitted ADU projects in your specific city or county.
The Benefits of Building an ADU in California
Building an ADU in California offers significant financial and lifestyle benefits. Homeowners can generate rental income to offset mortgage costs, house family members, or increase overall property value. In high-cost markets like the San Francisco Bay Area or Los Angeles, a well-built ADU can add hundreds of thousands of dollars in property value. With the right California ADU contractor by your side, the process can be smooth, compliant, and highly rewarding.