Attached ADU near Castro Valley, CA

DSA Architects designed an 850 sq. ft. second-floor ADU in Berkeley Hills for multi-generational living. Features 2 beds, 1 bath, open layout, Tilden Park views, roof deck, solar PV, heat pumps, and gray-water system.

Mendez and Son's Construction is a Bay Area ADU contractor offering design-build services in Palo Alto, Mountain View, San Mateo & Walnut Creek. They handle detached ADUs, garage conversions & JADUs, managing permits to final inspection.

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 Concord, San Jose, and Paramus, NJ.

Kyvos Construction offers home remodeling & ADU construction in Concord, CA. Services include kitchen & bathroom renovations, room additions, garage conversions, detached & attached ADUs, granny flats, and in-law suites.

Karl Kardel Company offers home remodeling, additions, and ADU construction in Oakland, Pasadena, and the Bay Area. Services include detached ADUs, garage conversions, granny flats, kitchen and bathroom renovations for residential properties.

YAHUA Construction Inc. is a California-based licensed general contractor with 20+ years of experience. Specializing in ADUs, remodeling, MEP, roofing, and more, they serve the Bay Area with quality, sustainable construction.

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.

ENE Smarthome, Inc. is a Bay Area contractor offering home remodeling, ADU construction, smart home upgrades, and accessibility improvements. Services include garage conversions, granny flats, aging-in-place remodels, and SB9-compliant ADU projects.

RWB Construction is a Lafayette, CA-based ADU contractor serving the Bay Area. They build detached ADUs, garage conversions, granny flats & in-law suites, managing design, permitting, and construction from start to finish.

At Ingenuity Construction Group, we specialize in crafting exceptional Accessory Dwelling Units (ADUs) that blend seamlessly with your existing property. With over 20 years of experience, our dedicated team ensures each ADU project is completed with meticulous attention to detail and superior craftsmanship.

Vargas Construction is a California ADU contractor offering detached, attached, garage, junior, and multifamily ADUs. They handle design, permitting, and construction with energy-efficient materials, custom interiors, and full amenities in 2–6 months.

Atlas General Construction delivers complete ADU construction for detached, attached, and converted structures. Our team manages every phase of development including zoning research, architectural coordination, structural engineering, Title 24 compliance, permit processing, foundation work, framing, roofing, plumbing, electrical systems, HVAC installation, interior finishes, and final inspections.

Dwelling Lab is an Oakland-based ADU design firm offering full-service planning, schematic design, construction drawings, permitting, and construction oversight for detached ADUs, attached additions, and garage conversions.

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.