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ADU Design-Build

ADU Design-Build in Orange County

Architecture, engineering, permits and construction under one contract — one accountable team from first sketch to final inspection.

Get your free quote→ (949) 374-7980
ADU Design-Build — watercolor illustration on an Orange County lot

Design-build means one licensed team owns your whole project — design, approvals and the build — so there are no gaps to fall through and no finger-pointing. Good design-build starts with feasibility: utility routes, fire access, sewer or septic needs, setbacks, finish allowances and local plan-check comments all shape the scope before construction begins.

Real project examples

Real ADU build examples from the Orange County & Los Angeles area

Browse L Square ADU work across multiple completed examples, including exterior details, interiors and finish inspiration.

View real ADU construction examples
Real ADU build example by L Square Design and Build Completed ADU example from L Square project work Finished ADU project example from L Square Design and Build L Square ADU construction example photo
01

Why design-build beats design-bid-build

With one contract you get a single point of accountability. There’s no handoff between a separate architect and builder, the design is drawn to be buildable on budget, and the schedule is fixed up front. Homeowners comparing a garage conversion ADU and a custom ADU can evaluate both paths before committing to plans.

02

Our process

Five clear stages — consultation, design, permitting, construction and handover — with weekly updates so you always know where your project stands.

03

What’s included

Architectural drawings, structural engineering, Title-24 energy compliance, the full city submittal, and construction by our own crews — packaged in one contract. Review the California ADU cost guide and Orange County permit guide before requesting a scope.

★

Why build with L Square

Design, permits and construction under one roof. L Square is a licensed Orange County design-build team (CSLB #1095476). One contract covers architecture, engineering, city approvals and our own build crews — so your ADU moves on a fixed schedule from first drawing to final inspection, across Orange County and Los Angeles.

01 · Architect-grade design
Every unit is drawn around your lot, light and privacy.
02 · Permit-ready, OC-savvy
We know each city’s ADU rules and clear the approvals for you.
03 · Built once, built right
Our own crews deliver on a fixed schedule, foundation to finishes.

Licensed · Insured · Bonded · CSLB #1095476 · Orange County & Los Angeles

Frequently asked questions

What does ADU design-build include?
Design-build means one team is responsible for the ADU from feasibility through final inspection. For L Square, that typically includes site review, concept layout, architectural drawings, structural coordination, Title 24 energy documentation, city submittal, plan-check responses, construction scheduling, inspections and the actual build. The goal is to catch budget and buildability issues while the plans are being drawn, not after an owner has already paid for drawings a builder cannot price cleanly.
Why is design-build useful for ADUs?
ADUs are small buildings with a lot packed into them: kitchen, bath, utilities, HVAC, egress, fire separation, setbacks and rental or family-use goals. When the designer and builder work separately, cost problems often show up late. In design-build, we talk about utility routes, sewer or septic, access, finish allowances and city comments while the plan is still flexible. That usually produces a cleaner scope and fewer surprises.
Do you handle the permit process?
Yes. We prepare the permit set, coordinate engineering and energy documents, submit to the city or county, answer plan-check comments and schedule inspections during the build. We do not promise that every city will approve on the same timeline, because plan check depends on jurisdiction workload and correction rounds. What we do control is submittal quality, fast responses and clear communication when the agency asks for changes.
How do you keep the price from changing after design?
We price from a defined scope: plans, known site conditions, utility assumptions, finish allowances and written exclusions. If a survey, soils report, panel upgrade, sewer issue or field discovery is outside the base scope, we flag it instead of burying it. Owner-driven changes are handled in writing before work proceeds. That discipline is the difference between a realistic construction contract and a vague early estimate.
Is design-build better for a rental ADU or a family ADU?
It works for both, but the priorities change. A rental ADU needs durable finishes, privacy, storage, straightforward maintenance and a layout that fits the local renter. A family ADU may need accessibility, quiet, daylight and easier connection to the main house. Design-build keeps those goals tied to cost and construction details from day one, so the finished unit fits the reason you built it.

Building an ADU in your Orange County city

ADU rules vary by city — we handle the specifics for your address. Statewide, California allows ADUs up to about 1,200 sq ft with 4-ft side and rear setbacks (CA HCD); your city may add its own details. For the statewide rules, see the CA HCD ADU Handbook.

Irvine ADU rules Anaheim ADU rules Santa Ana ADU rules Huntington Beach ADU rules ADU cost guide All areas we serve

Related guides & articles

ADU cost guide (2026)Honest ranges by type + the 7 things that move the price. California ADU laws 2026What changed this year for Orange County homeowners. OC permit requirementsSubmittals, fees and inspections, city by city. Detached vs attached ADUWhich layout fits your lot, budget and goals. Casita vs ADUWhat the words mean and how it affects permits. Is an ADU worth it?Rental income, resale value and the real ROI. How to hire an ADU contractorThe CSLB check and what to look for before you sign. Building an ADU in Los Angeles?How LA & LADBS differ — our LA design-build hub.

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your ADU?

Get a free, no-pressure quote from a licensed Orange County design-build team — and a plan drawn around your lot.

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