ADU Contractors near Castro Valley, CA
Kaplan Architects
49 Zoe Street, San Francisco, CA 94107
18.9 miles
Kaplan Architects added a 280 sq ft ADU to an existing garage in Crocker Highlands, Oakland. Built into a hillside, it features a kitchenette, full bath, and Tudor-style exterior, serving as office, studio, or rental unit.
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Mana Construction Inc
531 Ridge Ave, Vallejo, CA 94591
27.1 miles
Type Five
1336 Channing Way, Berkeley, CA 94702
16.2 miles
Type Five is a Berkeley, CA-based ADU builder offering custom backyard cottages, granny flats & in-law suites. They combine modular design, transparent pricing & streamlined construction for stress-free, high-quality detached ADUs built to last.
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Rosegold Builders, Inc.
358 South Abbott Avenue, Milpitas, CA 95035
21.2 miles
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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San Francisco ADU Solutions
967 Connecticut Street, San Francisco, CA 94107
21.9 miles
ADUs (accessory dwelling units) are self-contained homes on existing properties. California's 2020 laws simplified ADU permits statewide. Alpha ADU Solutions, a San Francisco-based ADU builder with 100+ team members, specializes in granny flats, garage conversions & in-law suites.
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Eano
42514 Albrae St, Fremont, CA 94583
10.8 miles
Eano offers custom on-site ADU design and build services, handling permits, construction, and financing. Their app tracks progress in real time. Licensed pros average 10+ years experience. Flexible 0% interest financing options available.
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BUILD 33
21045 Cory Court, Cupertino, CA 95014
27.3 miles
BUILD 33 (CSLB #1051529) is a licensed general contractor based in Cupertino, CA, serving California, Arizona, Nevada, and Louisiana. They offer home additions, flooring, painting, plumbing, electrical, and more. Free quotes available.
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Realty Builders Inc.
50 California Street, San Francisco, CA 94111
19.2 miles
Realty Builders Inc. is a licensed ADU contractor specializing in custom accessory dwelling units, including in-law suites, granny flats, garage conversions & rental units, offering streamlined permitting & guaranteed workmanship.
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DNM Architecture
1A Gate 5 Road, Sausolito, CA 94965
26.4 miles
DNM Architecture is a California-based firm specializing in ADU design and permitting. Their ADUxDNM program covers site analysis, design, permitting, and construction management, offering detached ADUs, garage conversions, and more.
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ASL Remodeling
690 Saratoga Avenue, San Jose, CA 95129
27.4 miles
ASL Remodeling is a California licensed ADU contractor (CSLB #1060310) with 20+ years experience and 300+ completed projects. Services include detached ADUs, garage conversions, granny flats, JADUs, and in-law suites with full design-build support.
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Clarity Construction
111 North Market Street, San Jose, CA 95113
27.2 miles
Clarity Construction is a Bay Area contractor specializing in ADUs, home additions, and remodeling in Sunnyvale, Palo Alto, and South San Francisco. Services include backyard ADU builds, in-law suites, permits, and kitchen remodels.
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ProStruct Engineering
450 Folsom Street, #1502, San Francisco, CA 94105
19.7 miles
ProStruct Engineering offers ADU structural engineering services across California, providing permit-ready plans and calculations for detached ADUs, garage conversions, granny flats, and more, with a 2–3 week turnaround.
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Leon's Construction Inc.
3333 Vaca Valley Parkway, Poway, CA 95688
47.6 miles
Leon's Construction Inc. offers ADU construction services in Escondido, Encinitas, and San Marcos, CA. They build backyard cottages, basement apartments, tiny homes, and more using durable, energy-efficient materials.
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Northbay Home Solutions
47 Paul Drive, San Rafael, CA 94903
30.4 miles
Northbay Home Solutions offers full-service ADU construction in San Rafael, San Francisco & North Bay. Services include detached ADUs, garage conversions & JADUs, covering design, permits & build.
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GR Innovative Builders Inc.
12488 San Pablo Avenue, Richmond, CA 94805
21.5 miles
GR Innovative Builders Inc. is a Bay Area ADU contractor specializing in accessory dwelling units, granny flats, and in-law suites. Completed projects in Richmond, Oakland, Lafayette & Pinole. Featured in Sunset Magazine.
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Other cities in California
What you need to know
ADU Contractors in Castro Valley: Building in Alameda County's Unincorporated Community
Castro Valley is a unique location for ADU construction because it is an unincorporated community governed by Alameda County rather than an independent city. This means that homeowners looking to build an Accessory Dwelling Unit must work with the Alameda County Planning Department and follow Alameda County's specific zoning codes and building regulations. Experienced ADU contractors in Castro Valley understand this distinction and are well-versed in navigating county-level permitting processes, which differ significantly from those of neighboring incorporated cities like San Leandro or Hayward.
Key ADU Regulations Castro Valley Contractors Must Follow
Because Castro Valley falls under Alameda County jurisdiction, ADU contractors must comply with the county's ADU ordinance, which aligns with California state law but includes local nuances. Some important regulatory considerations include:
- Setback requirements: Detached ADUs in unincorporated Alameda County typically require a minimum 4-foot rear and side yard setback.
- Maximum ADU size: Detached ADUs can generally be up to 1,200 square feet, depending on lot size and zoning designation.
- Height limits: Detached ADUs are typically limited to 16 feet in height, though this can vary based on proximity to the primary dwelling.
- Owner-occupancy rules: California state law has suspended owner-occupancy requirements for ADUs through January 1, 2025, which applies to Castro Valley properties as well.
- Utility connections: Separate utility connections may be required, and contractors must coordinate with East Bay Municipal Utility District (EBMUD) for water and sewer services.
Why Hire a Local ADU Contractor in Castro Valley?
Hiring a contractor with direct experience in Castro Valley and Alameda County is essential for a smooth ADU project. Local ADU contractors are familiar with the Alameda County Building Services Agency, which handles permit applications, inspections, and plan checks. They understand the typical timelines, required documentation, and how to address common issues that arise during the approval process. Castro Valley's hillside terrain in many neighborhoods also presents unique grading and foundation challenges that experienced local contractors are equipped to handle.
Types of ADUs Popular in Castro Valley
Castro Valley homeowners are increasingly choosing ADUs to address the Bay Area's housing demand and to generate rental income. The most popular ADU types in the area include:
- Detached ADUs: Standalone structures built in the backyard, ideal for larger lots common in Castro Valley's residential neighborhoods.
- Garage Conversions: Converting existing attached or detached garages into livable ADU space.
- Junior ADUs (JADUs): Units up to 500 square feet created within the existing footprint of the primary home.
Start Your Castro Valley ADU Project Today
Working with a qualified ADU contractor in Castro Valley ensures your project meets all Alameda County requirements while maximizing your property's potential. From initial design and permitting through final inspection, the right contractor will guide you every step of the way, helping you add value to your home in one of the East Bay's most desirable communities.