ADU Construction in Costa Mesa, CA
Serhal Builders builds ADUs in Costa Mesa, including detached backyard units, garage conversions, attached ADUs and junior ADUs.
Costa Mesa allows ADUs and junior ADUs in all residential districts. The city sets a minimum ADU size of 150 square feet, makes parking optional, and applies objective design standards, including setbacks for second-story or two-story ADUs.
We’re a licensed, veteran-owned general contractor (CSLB #1074208) with more than 31 years in construction, and we build ADUs across Orange County.
Complete ADU Services in Costa Mesa
One licensed contractor from design and permits to the final inspection.
Detached ADUs
A separate backyard home built from the ground up, with its own entrance, kitchen and bathroom.
Garage Conversions
We turn an existing garage into a full living space, often the most budget-friendly way to add a unit.
Attached ADUs
An addition connected to your home with its own entry, kitchen and bath, so family stays close but independent.
Junior ADUs (JADU)
A unit of up to 500 square feet created inside your existing home, with its own entrance.
Design & Floor Plans
In-house design, plans from our design partner, or your own architect’s plans. We work whichever way suits you.
Permits & City Approval
We prepare and submit the permit package and handle plan-check corrections with the city.
Utilities & Systems
Electrical, plumbing, sewer, water and gas tie-ins planned early so there are no surprises mid-build.
Kitchens, Baths & Finishes
Cabinets, counters, tile, flooring and fixtures, all handled by the same team that remodels full homes.
Solutions & Benefits
Every lot is different. These are the three ways most homeowners add a unit.
Detached ADUs & Garage Conversions
A detached ADU gives you a separate backyard home with its own entry, kitchen and bath. A garage conversion reuses an existing structure and is often the most budget-friendly way to add a unit.
Attached ADUs & Junior ADUs
An attached ADU connects to your home but lives independently. A junior ADU is up to 500 square feet created inside your existing home, a good fit for family members who want their own space nearby.
Plans & Permits Your Way
Use our in-house design, our design partner, or plans you already have. We prepare the permit package, respond to plan-check comments and coordinate inspections until final sign-off.
What Costa Mesa Homeowners Should Know
Our Working Process
Building an ADU in Costa Mesa has more steps than a remodel. Our process keeps it clear and manageable.
ADU Construction in Nearby Cities
We also build ADUs in these Orange County cities: