Greenberg Construction builds custom ADUs, including detached units & garage conversions. Services include 3D renderings, dedicated project management, eco-friendly options & expert design guidance to add value & living space to your property.
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Nestadu is a full-service ADU builder offering custom site-built and prefab accessory dwelling units. Prefab models range from $115K–$317K. Custom builds start at $400/sq ft. Financing options include HELOCs, construction loans, and CA grants.
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Dream Build Services is a full-service ADU contractor in Fremont, CA, offering detached ADUs, garage conversions, basement conversions, and JADUs. Services include design, permits, electrical, plumbing, HVAC, and solar integration across the East Bay.
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AKD Homes is a Bay Area ADU contractor with 20+ years of experience. They offer full-service ADU design and build, including detached ADUs, custom designs, and conversions from Berkeley to San Jose.
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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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Eco Scale Construction builds ADUs in Sunnyvale, Los Altos & Palo Alto, CA. Services include detached ADUs, garage conversions & JADUs. Costs range from $80K–$400K+. Fully compliant with California ADU regulations.
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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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Your Prefab ADU will be delivered and installed to your site. All ready to enjoy a sustainable home to last for generations.
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Barcci Builders specializes in ADU construction across the Bay Area, offering design, permitting, and build services. With 40+ completed units, they handle JADUs, garage conversions, attached, and detached ADUs, with costs ranging from $60K to $400K+.
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Custom ADU builders in Palo Alto, CA, specializing in granny flats, detached ADUs & backyard cottages. Personalized design, permitting, and full construction management for quality accessory dwelling units.
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Home Quality Remodeling Inc. is a licensed Bay Area general contractor (CSLB #838832) with 20+ years of experience. Services include kitchen & bathroom remodeling, room additions, ADUs, and outdoor living across California and New Jersey.
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Samara's Backyard ADU offers prefab accessory dwelling units for California homeowners. Five sizes available, including the 950 sq ft XL 10. Factory-built, fire-resistant, energy-efficient, with full-service permitting, installation & flexible financing.
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Feldman Construction specializes in custom ADU design and construction across the Bay Area, including San Mateo and Santa Clara County. They build detached ADUs, granny flats, and in-law suites to boost property value and expand living space.
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Ingenious General Construction is a BBB-certified, licensed contractor in Walnut Creek, CA, serving the East Bay. With 20 years of experience, they offer ADUs, kitchen & bathroom remodeling, home additions, pool construction, and landscaping.
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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.
read moreCastro 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.
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:
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.
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:
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.