Eureka Modular builds steel frame modular ADUs and single family homes. Steel framing offers durability, design flexibility, and sustainability. Ideal for detached ADUs, backyard cottages, granny flats, and casitas with efficient, precise construction.
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ADU1 helps multifamily property owners add ADUs to boost income. Add up to 25% more units plus 2 detached ADUs. Services include a $250 feasibility report, full design-build, and free weekly Q&A sessions every Wednesday.
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Avorino specializes in ADU construction, offering detached, attached, garage conversion, and above-garage units. Projects range from $250K–$400K, covering design, permitting, and build phases over 10–14 months.
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Cajigas Construction Inc. is a licensed ADU builder with 35+ years of experience serving Sacramento, Stanislaus, and San Joaquin Counties. Services include detached ADUs, JADUs, garage conversions, new home construction, and REO property services.
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Progressive Builders LA offers full-service ADU construction in Los Angeles, handling detached ADUs, garage conversions, granny flats & in-law suites. Custom design, quality materials, on-time delivery & accessible pricing for all project sizes.
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Loona Construction Inc. is a San Francisco ADU contractor specializing in detached ADUs, garage conversions, attached ADUs, and JADUs. They handle design, permitting, and construction, helping homeowners add rental income or family housing.
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Shed Shop offers ADUs (Accessory Dwelling Units) via their Mini Cottage program. Sizes range from 192 to 480 sq. ft. Services include foundation, plumbing, electrical, permits & more. Available in select cities.
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Inspired ADUs is an architect-led ADU design firm serving the Bay Area and Southern California. With 20+ years of experience and 250+ ADUs permitted, they offer custom, panelized, and modular ADU solutions, plus interior design and SB9 lot split services.
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ADUscale is an independent ADU advisory service offering feasibility assessments, contractor verification, escrow-based payment protection, and construction oversight. Fixed-fee, conflict-free guidance for homeowners planning detached ADUs, garage conversions, or backyard cottages.
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HardyBuilt Custom Construction Inc. is a licensed General Contractor in Humboldt County, CA, specializing in custom homes, ADU builds, whole house remodels, additions, and kitchen & bathroom renovations built for Marine Climate Zone 4C.
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Bay Builders & Remodeling specializes in custom ADU construction across Santa Clara, San Mateo, and East Bay. Services include attached, detached, garage conversions, and JADUs, helping homeowners add rental income, family housing, or workspace.
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Larson Shores Architects is a San Francisco-based firm offering residential, ADU, and commercial design services. Founded in 2007 by Josh Larson, they specialize in new builds, garage conversions, in-law suites, and full permit navigation across the Bay Area.
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MGMW Remodeling INC is a Los Angeles ADU contractor specializing in accessory dwelling units. Services include detached ADU construction, garage conversions, architectural design, permitting, and full project management from planning to completion.
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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.
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Woollard Construction is a family run general contractor specializing in ADUs and bathroom remodels. Formed over 25 years ago in Temecula, California, we deliver professional building projects with care and precision in Temecula and Murrieta.
read moreCalifornia 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.
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.
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:
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.
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.