Basement Conversion near Foothill Ranch, CA

OakADU is a full-service ADU contractor in Los Angeles & Southern California, offering design, permitting, construction & property management for detached ADUs, garage conversions, attached ADUs & interior conversions.

Golden ADU, serving Southern California since 2021, specializes in custom ADU construction including garage conversions and detached backyard cottages. They offer flexible financing with no upfront costs, completing most projects in 6–12 months.

ADUscale is an independent ADU advisory service offering feasibility assessments, contractor verification, escrow-based payment protection, and construction oversight. Fixed-fee, conflict-free guidance for homeowners planning detached ADUs, garage conversions, or backyard cottages.

Joel & Co. Construction, serving Los Angeles since 1983, offers expert residential & commercial construction, including custom homes, kitchen & bathroom remodels, ADUs, room additions, and general contracting across Beverly Hills, Santa Monica & beyond.

Cornejos Builders offers ADU construction, garage conversions & home additions in LA & Orange County. 24 ADUs completed in 4 years. Costs range $80K–$250K. Licensed, insured, bonded. 1-year warranty included.

ADU Los Angeles (ADLA) is a specialized ADU contractor serving LA County. They offer consulting, custom design, construction, garage conversions, basement ADUs, attached and detached units, helping homeowners maximize property value.

Premium ADU is a Los Angeles ADU specialist offering design, permitting, and construction of detached ADUs, garage conversions, and JADUs. Operating since 2021 with an in-house team, projects typically complete in 6–12 months.

JP Homes is a licensed ADU contractor in Southern California, serving Los Angeles, Orange County, Riverside & San Bernardino. They offer full-service ADU construction including detached units, garage conversions & more.

Build Method Construction is a licensed ADU contractor in Los Angeles County with 25+ years of experience. They build detached ADUs, garage conversions, JADUs, and more—handling design, permits, and construction for single and multi-family properties.

Bartona Builders specializes in ADU construction in Los Angeles, offering detached ADUs, garage conversions, and in-law suites. They manage the full build process, ensuring code-compliant construction that adds value to residential properties.

Liebo Builders is a Southern California ADU contractor specializing in detached, attached, garage conversion & interior ADUs. Services include custom design, permitting, and construction for guest houses, rentals & home offices.

Long Beach Elite ADU Solutions specializes in ADU construction and garage conversions in Long Beach, CA. Services include detached ADUs, JADUs, basement and above-garage units. 15+ years experience, 150+ completed projects.

The ADU Pro® is a licensed ADU contractor in Chino, CA, serving Fontana and Southern California. Specializing exclusively in ADU construction, they offer detached ADUs, garage conversions, and granny flats with a lifetime transferable warranty.