ADU Construction in Orange, CA

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ADU Builder

ADU Construction in Orange, CA

Serhal Builders builds ADUs in the City of Orange, including detached backyard units, garage conversions, attached ADUs and junior ADUs. We’re based in nearby Fullerton.

Orange is home to the Old Towne Historic District and several Eichler neighborhoods, and those areas come with extra design review. An ADU on a historic property needs a Historic Resource Assessment, and the design is expected to match the main house in roof pitch, materials, colors and window style.

We’re a licensed, veteran-owned general contractor (CSLB #1074208) with more than 31 years in construction, and we’ve built ADUs throughout northern Orange County.

Full-Service Solutions

Complete ADU Services in Orange

One licensed contractor from design and permits to the final inspection.

Detached ADUs icon
Detached ADUs

A separate backyard home built from the ground up, with its own entrance, kitchen and bathroom.

Garage Conversions icon
Garage Conversions

We turn an existing garage into a full living space, often the most budget-friendly way to add a unit.

Attached ADUs icon
Attached ADUs

An addition connected to your home with its own entry, kitchen and bath, so family stays close but independent.

Junior ADUs (JADU) icon
Junior ADUs (JADU)

A unit of up to 500 square feet created inside your existing home, with its own entrance.

Design & Floor Plans icon
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 icon
Permits & City Approval

We prepare and submit the permit package and handle plan-check corrections with the city.

Utilities & Systems icon
Utilities & Systems

Electrical, plumbing, sewer, water and gas tie-ins planned early so there are no surprises mid-build.

Kitchens, Baths & Finishes icon
Kitchens, Baths & Finishes

Cabinets, counters, tile, flooring and fixtures, all handled by the same team that remodels full homes.

Why Choose Us

Solutions & Benefits

Every lot is different. These are the three ways most homeowners add a unit.

Detached ADU
Attached & JADU
Plans & Permits

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.

Local Knowledge

What Orange Homeowners Should Know

Historic properties – A Historic Resource Assessment is required for an ADU or JADU in a Historic Overlay District or on a property in the city's historic inventory.
Old Towne and Eichler design standards – Projects in Old Towne must show compliance with the Secretary of the Interior's Standards and the city's Historic Preservation or Orange Eichler Design Standards, prepared by a qualified preservation professional.
Planning first – Orange requires Planning approval before building plan check. The city's Planning Division can be reached at 714-744-7220.
Rules change – Some local rules have been updated to follow newer state law, so we confirm current requirements with the city before design.
ADU floor plans for a Orange home
Homeowners reviewing ADU floor plans
Simple Process

Our Working Process

Building an ADU in Orange has more steps than a remodel. Our process keeps it clear and manageable.

We look at your lot, utilities and goals and recommend the ADU type that fits.
We design in-house, with our partner, or from your plans, then handle submittal and plan-check corrections with the city.
Our crew builds the ADU and coordinates every inspection through to final sign-off.
Quick Answers

Frequently Asked Questions

Can I build an ADU in Old Towne Orange?
Yes, but expect extra review. ADUs on historic properties need a Historic Resource Assessment, and the design must meet the city's historic preservation standards.
Does my ADU have to match my house in Orange?
The city expects the ADU's style to match the main house in roof pitch, colors, materials and window style. Colored elevations are needed if the design differs.
Who reviews ADUs in the City of Orange?
Planning reviews first (714-744-7220), then the Building Division handles plan check.
Are you a licensed contractor?
Yes. Serhal Builders is a licensed California general contractor (CSLB #1074208). We're veteran-owned and family-run, with more than 31 years of construction experience.
Do you handle the plans and permits?
Yes. We can design your ADU in-house, work with our design partner, or build from plans you already have. Either way we prepare the permit package and handle corrections with the city.
Can I convert my garage into an ADU?
In most cases, yes. California law generally does not allow cities to require replacement parking when a garage is converted into an ADU. We check your specific property before design.
How do I get started?
Call us at 949-829-4999 or request a quote online. We'll talk through your goals, look at your property and explain which ADU type fits best.