Attached ADU near Rancho Santa Margarita, CA

SE Builders Inc completed an ADU project in Fullerton, CA, transforming a structure into a modern living space. Features include updated framing, durable finishes, eco-friendly materials, energy-efficient systems, and low-maintenance landscaping.

Sennikoff Architects, based in California, specializes in ADU design, custom homes, and remodels in Long Beach and Southern California. Led by licensed architect Steven Sennikoff, the firm offers detached ADUs, garage conversions, and JADUs with full permit coordination.

US Modular Inc. is a trusted ADU builder in Riverside County, CA, with 35+ years of experience. They offer prefab ADUs, garage conversions & casitas starting at $150,000, completed in 6–9 months.

TNT Design & Build specializes in ADUs, garage conversions & room additions in San Diego's North County. 15 years experience, in-house management, free architectural design, prices from $325/sqft with guaranteed budget & timeline.

Vertebrae is an LA-based, woman-owned architecture studio founded in 2012, specializing in ADU design and small-space living. Award-winning projects include the 2025 Architizer A+ Award and 2023 AIA LA Honor Award winners.

Potato Construction Inc., based in Rosemead, CA, is a licensed ADU contractor with 15+ years of experience. They build detached ADUs, garage conversions, attached ADUs, and JADUs across the San Gabriel Valley and greater Los Angeles area.

An accessory dwelling unit (ADU) is a secondary home on a single-family lot with kitchen, bath, and sleeping space. Xavier Design Group helps Southern California homeowners build ADUs with trusted contractors and transparent pricing.

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.

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.

Papaya Construction Group is a licensed design-build ADU contractor in Orange County, CA. Founded in 2018, they offer detached ADUs, garage conversions, attached units & above-garage builds across Irvine, Anaheim & more.

An ADU is a secondary residential unit on the same property as a primary home. JL Biber Construction Inc., a licensed ADU builder in Riverside, California, offers full-service garage conversions, granny flats, and detached ADU construction.

Custom ADU Builder specializes in detached ADUs, attached ADUs, garage conversions & JADUs. Projects complete in ~3 months. Pricing starts at $235/sqft. Turn-key builds include quartz countertops, tile showers & luxury vinyl flooring.

Ohayon Construction is a licensed Los Angeles ADU contractor since 2008. They build detached ADUs, garage conversions, attached ADUs & JADUs. Serving Beverly Hills, Santa Monica & more. Free consultation available.

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.