Attached ADU in California

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.

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.

View ADU Builders is a trusted Los Angeles ADU contractor specializing in detached ADUs, garage conversions, attached ADUs & in-law suites. Costs range from $80K–$350K+. Free 3D design consultations available.

Ataman Studio is a trusted ADU contractor in Los Angeles, serving all of California. Full-service design, permitting, and construction for detached ADUs, garage conversions, and in-law units, with compliance to local zoning and state regulations.

Murray Lampert, San Diego's trusted ADU builder since 1975, offers full design-build services including granny flats, in-law suites, and garage conversions. With 50+ years of experience, they deliver custom, high-quality accessory dwelling units tailored to your needs.

West Coast Building and Design builds ADUs in California, including granny flats, garage conversions, and detached units. They help homeowners boost property value, house family members, or earn rental income through structured, process-driven construction.

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.

Urbatect Development LLC is a California & Washington ADU contractor offering custom homes, garage conversions, JADUs & detached ADUs. 15+ years experience, 3,500+ projects, fixed pricing, fast permitting & 3D design.

Deharo Construction is a trusted ADU builder serving Livermore, Pleasanton, and Dublin. Specializing in accessory dwelling units, new construction, and home additions, they deliver custom granny flats, detached ADUs, and in-law suites across the Tri-Valley area.

We are a family-first, boutique residential design & build firm serving the Orinda and East Bay community. We’re not just service providers — we’re your neighbors. We understand the local permitting process, the hillside terrain, the fire-hazard restrictions, and the thoughtful planning needed to create homes that truly work for East Bay families.

Lars Remodeling & Design is a San Diego design-build firm with nearly 40 years of experience. Services include whole home remodels, room additions, second-story additions, and in-law suites, managed by an integrated team of architects, designers, and builders.

Lincoln James Construction (License #B-860952) builds custom ADUs in Ventura & Los Angeles Counties since 2005. Services include detached units, garage conversions, basement ADUs, in-law suites & rental-ready builds across Southern California.

Building an ADU in Riverside takes 8–16 months. JDB Builders guides homeowners through design (1–3 months), permitting (2–4 months), construction (4–8 months), and final inspections (1–2 months) for granny flats, garage conversions, and more.