What types of ADUs do you build in Orange County?

Detached ADUs, attached ADUs, Junior ADUs, and garage conversions — every permitted typology under California state ADU law.

What should I look for in an ADU builder in Orange County?

Three things matter most in Orange County: a California General-B license (Avorino holds #1107538), design + structural engineering + permitting handled in-house so nothing is lost between separate firms, and a fixed-price contract. Avorino keeps all of it under one roof across 34+ OC cities — so your ADU is contracted and built by one company, not coordinated across subs.

What are typical ADU build windows in Orange County?

Detached: 5–8+ months. Attached: 5–8+ months. Junior ADU: 4–6+ months. Garage conversion: 4–6+ months. Windows vary with city, plan-check timing, and finish-level decisions.

What do ADUs typically cost in Orange County?

Detached ADUs typically run $245K–$440K+. Attached ADUs $245K–$375K+. Junior ADUs $85K–$145K+. Garage conversions $145K–$165K+. Use the Avorino cost estimator for a calibrated range on your specific project.

Do I need to hire an architect separately?

No — Avorino handles design, structural engineering, Title 24 calculations, and permitting in-house. Single point of accountability from concept through final inspection.

ADU · Avorino

Custom ADUs across Orange County.

Get a Free Consultation Or call(714) 900-3676

Your OC builder · permits in-house · free consultation

Licensed B-#11075387+ yrs · Orange County

Detached ADU.

Standalone unit on your property. Most rental upside, longest schedule, biggest ROI when the property has the room.

$245K – $440K+Cost range

5–8+ moBuild window

Best for: Properties with side or rear setback room for a free-standing unit.
Typical size: 500 – 1,200 sqft
Bedrooms: Studio – 3 BR
Includes: New foundation, full kitchen + bath, independent utilities.

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Tell us about your vision.

Send the address and your ADU idea. Avorino will review it and follow up with clear next steps.

7+YearsOrange County experience
B-#1107538LicenseCalifornia General-B
34+OC Cities + CommunitiesCoverage across all of Orange County
4.9★RatingYelp

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Recent builds

A few of our favorites.

See more on Instagram@avorinoconstruction

Free AI tools

AI tools that help you bring your vision to reality.

Calibrated against active Avorino OC builds — not stock estimates. Run them anonymously; the results are yours to keep or share with us.

AI ADU Cost Estimator

$245K – $440K+Detached ADU · typical OC range

Instant cost-range read on your ADU — calibrated to your city, square footage, finish level, and ADU type.

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AI ADU ROI Calculator

10-yrRental income + payback projection

Project rental income, payback period, and long-term return on your ADU — modeled on real Orange County rents.

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Inside the build

Design, permits, and construction — under one roof.

An accessory dwelling unit is a self-contained home on your existing lot — detached, attached, or a conversion. We help you from step one: site check, design, permits, and the build, all in-house.

Custom architectural plans + structural engineering, included
Title 24 energy calculations handled in-house
City submittals + plan-check corrections managed by Avorino
One in-house team, weekly progress updates, organized and on track

Process

Five steps to a permitted ADU.

We handle every step in-house, from design to the build. Scroll through the build — the wireframe behind the copy swaps per phase.

Free consultation

Setbacks, easements, utility lines, neighbor friction reviewed together. We tell you what your vision can carry before drawings.

Orange County ADU questions, answered

What types of ADUs do you build in Orange County?: Detached ADUs, attached ADUs, Junior ADUs, and garage conversions — every permitted typology under California state ADU law.
What should I look for in an ADU builder in Orange County?: Three things matter most in Orange County: a California General-B license (Avorino holds #1107538), design + structural engineering + permitting handled in-house so nothing is lost between separate firms, and a fixed-price contract. Avorino keeps all of it under one roof across 34+ OC cities — so your ADU is contracted and built by one company, not coordinated across subs.
What are typical ADU build windows in Orange County?: Detached: 5–8+ months. Attached: 5–8+ months. Junior ADU: 4–6+ months. Garage conversion: 4–6+ months. Windows vary with city, plan-check timing, and finish-level decisions.
What do ADUs typically cost in Orange County?: Detached ADUs typically run $245K–$440K+. Attached ADUs $245K–$375K+. Junior ADUs $85K–$145K+. Garage conversions $145K–$165K+. Use the Avorino cost estimator for a calibrated range on your specific project.
Do I need to hire an architect separately?: No — Avorino handles design, structural engineering, Title 24 calculations, and permitting in-house. Single point of accountability from concept through final inspection.

Custom ADUs across Orange County.

Detached ADU.

Tell us about your vision.

A few of our favorites.

AI tools that help you bring your vision to reality.

AI ADU Cost Estimator

AI ADU ROI Calculator

Design, permits, and construction — under one roof.

Five steps to a permitted ADU.

Free consultation

Drawings

City permits

Construction

Walk + warranty

Orange County ADU questions, answered

Serving 34+ Orange County cities & communities.