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.

Valley Boutique Builders is a licensed Bay Area ADU contractor offering full-service accessory dwelling unit construction, custom home additions, kitchen and bathroom remodeling, and new construction with free initial consultations.

ADU Home Addition is a leading Bay Area ADU contractor with 12+ years of experience. They specialize in custom ADU construction, in-law suites, garage conversions, home additions, and rental-optimized ADUs, handling design, permits, and full construction.

Bay Area Home Remodelers builds ADUs in Daly City, San Francisco & San Jose. Services include garage conversions, granny flats, JADUs & detached units. Full project support from permits to completion.

Urban Shore Builders offers full-service ADU design & construction, including garage conversions, detached units & additions. As a turnkey ADU contractor, they handle permits, design & build. Services include plumbing, electrical, HVAC & retaining walls.

Edri Construction, Inc. in Burlingame offers full-service ADU construction across the Bay Area, including garage conversions, detached ADUs, attached additions, and custom interiors, with energy-efficient builds and multi-generational living solutions.

Custom Home is a Bay Area ADU contractor (CSLB #986048) with 160+ projects since 2005. They build detached, attached, junior ADUs & garage conversions across South Bay & Peninsula, with costs from $120K–$500K+.

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.

ON Design & Remodeling is a Bay Area ADU builder offering home additions, garage conversions, granny flats, and in-law suites. They help homeowners expand living space, boost property value, and generate rental income.

Mola Construction is a trusted ADU builder in San Jose with 20+ years of experience. They offer custom ADUs, kitchen remodels, home additions, and full remodeling services across the Bay Area, ensuring California code compliance.

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.

Step-up Construction is a San Jose ADU contractor specializing in garage conversions, attached additions, and detached backyard ADUs. Costs range from $80K to $475K. They guide homeowners through permits, zoning, and San Jose's ADU regulations.

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.

Bay Area design-build ADU specialists. One project, one point of contact — design, engineering, permitting, and construction from start to finish. CSLB #1130783.