ADU Builders in Los Angeles and Orange County
Los Angeles County permits more accessory units than most states build, and local knowledge pays for itself here. The city runs a standard plan program of pre-approved designs, the county runs a separate one, and Long Beach, Pasadena, Santa Monica and Beverly Hills each handle their own counter. A hillside lot in the Valley and a flat lot in Irvine are different projects with different costs. This page covers design-build firms whose main business is the LA and Orange County market. The good ones name the cities they have actually permitted in, not the ones they will drive to. We rank on local permit record, crew capacity, and how clearly a finished unit is priced.
- 1
A full-service ADU designer and builder with 600+ completed projects across Greater Los Angeles, handling everything from feasibility to final handover in-house with a dedicated 19-person team.
- 2
Southern California full-service ADU contractor with 500+ completed projects and backing from the TESH Group ecosystem. Offers 15 pre-engineered designs using panelized steel construction, plus custom builds, serving single-family and multifamily clients across Los Angeles, Ventura, and Orange counties.
- 3
Design-build studio founded by a UCI MBA that handles full in-house ADU projects across Orange County and LA with 200+ completed builds. One team, one contract from sketch to final inspection.
- 4
Design-build firm handling the full ADU journey from initial site visit through construction completion, serving 64 neighborhoods across greater Los Angeles and Orange County with transparent pricing and a stated 100% permit approval rate.
- 5
Pasadena and San Gabriel Valley specialist with over 150 completed ADU projects, detached and attached units, junior ADUs, and garage conversions, targeting 4-to-6-month timelines and offering pricing from $200 to $400 per square foot depending on unit type.
- 6
Family-owned Los Angeles ADU builder with seven years of experience, 120+ completed projects, and guaranteed pricing. Full design-build service from site assessment through construction, serving the greater LA area with transparent milestone-based payments.
- 7
Architect-led builder that has designed and built over 100 ADUs across Los Angeles since 2019, combining custom ADU design with construction management and a track record serving 70+ homeowners across diverse LA neighborhoods.
- 8
A Long Beach design-build firm with over a decade of ADU experience and dual contractor licenses, handling everything from detached units and garage conversions to junior ADUs.
- 9
South Bay design-build firm with three decades of construction experience, in-house architecture and engineering, and a portfolio of completed projects ranging 400 to 1000 square feet. Operates under a no-subcontracting model.
- 10
A Long Beach-based design-build firm offering fixed, all-inclusive pricing and on-time delivery guarantees, with an extensive portfolio of completed ADU projects across Los Angeles and Orange County.
- 11
Orange County ADU builder with 42 years of experience and a leadership team combining real estate expertise, custom home craftsmanship, and construction management. Offers 10 custom plans across Orange County.
- 12
A licensed Glendale-based ADU contractor (Shenk Construction, CSLB
- 13
Westside ADU specialist handling design, permitting, and construction for new attached units and detached builds on owner property. CSLB licensed, serving Los Angeles County with a stated nine-month timeline.
- 14
Luxury-focused Encino general contractor founded in 2013, offering ADU construction alongside custom home builds and commercial projects, serving estates and high-value properties throughout Los Angeles and Orange Counties.
- 15
Los Angeles design-build contractor with 20+ years of construction experience, offering end-to-end custom ADU services across LA, Ventura, and Orange County.
- 16
Family-owned Culver City general contractor licensed for ADUs, junior ADUs, garage conversions, and additions alongside kitchen and bathroom remodeling, offering full A-to-Z service from design through permit and construction.
Frequently asked questions
What is the difference between a design-build firm and a traditional contractor?
Many builders on this list operate as design-build firms, meaning they handle the entire journey from initial site visits and architectural sketches to final construction and inspections. This approach often uses one team and one contract to manage the project from start to finish.
Can I find builders who specialize in specific types of ADUs like garage conversions or junior ADUs?
Yes, several listed professionals specialize in specific formats such as detached units, attached units, garage conversions, or junior ADUs. Some companies even focus their expertise on specific geographic areas like Pasadena or Long Beach.
Are there builders who offer pre-designed or standardized plans to speed up the process?
Several companies offer pre-engineered or custom plans to help streamline the building process. Some providers specifically utilize panelized steel construction or offer a set number of pre-designed options to simplify your choice.
How can I ensure the pricing for my ADU project won't change unexpectedly?
You can look for builders that offer guaranteed or fixed, all-inclusive pricing. Some firms provide transparent pricing models from the beginning to help you manage your budget throughout the construction process.