Stone Development builds ADUs across Orange County, helping homeowners evaluate lot fit, permit path, utility scope, and whether detached new construction or conversion work makes the best financial sense.
ADU demand is strong because the underlying homeowner goals are strong: rental income, multigenerational living, flexible housing, and smarter land use. The hard part is not wanting the ADU. It is underwriting the real approval, utility, and construction path before design costs pile up.
Why homeowners use us
Local office
1 Jenner Suite 150, Irvine, CA 92618
Call (949) 508-6763 to talk through scope, timing, and whether this service is the right fit for the property.
Typical investment
$150,000 to $375,000+
Detached units, conversions, and larger two-bedroom programs sit on different cost bands.
Typical timeline
10 to 18 months
From early planning through permit, construction, and final signoff.
Best fit
Detached ADUs, conversions, and feasibility reviews
Especially strong for homeowners comparing rental return, family use, and addition alternatives.
Bing and local search work better when a service page answers the commercial question directly instead of hiding it in a home page or portfolio gallery. These sections give the page clearer topical depth while keeping the copy useful for homeowners who are still choosing a path.
The smartest first question is not square footage. It is use case. Rental income, family housing, office space, and resale strategy create different program priorities and different risk tolerances. Once that is clear, lot fit, utility routing, parking assumptions, and approval friction become much easier to evaluate honestly.
The state framework matters, but site context still matters. Irvine, Costa Mesa, and other Orange County cities create different front-end realities through lot coverage, utility conditions, neighborhood patterns, and review workflows. A county-level average is useful, but the project succeeds or fails at the parcel level.
ADUs fail when owners move into design too quickly or compare detached construction with conversions as if they are the same scope. We front-load the feasibility conversation, pricing logic, and permit strategy so the homeowner knows what they are actually committing to before the spend accelerates.
Detached ADUs often range from $150,000 to $375,000+, while conversions or smaller units may land below that depending on size and utility scope.
No. We can help evaluate detached ADUs, garage conversions, and other secondary-unit strategies based on the property and the homeowner goal.
Many Orange County ADU projects run roughly 10 to 18 months from early scope planning through final occupancy.
We focus heavily on Orange County with especially strong relevance for Irvine, Costa Mesa, and other cities where homeowners are actively comparing ADUs with additions.
Stone Development serves Orange County homeowners who need a general contractor for kitchens, bathrooms, ADUs, additions, whole-home renovations, custom homes, and reconstruction work.
Stone Development works with Irvine homeowners on remodeling and construction projects that need scope clarity, permit awareness, HOA sensitivity, and stronger finish discipline.
Stone Development supports Costa Mesa homeowners who need kitchen remodels, ADUs, bathrooms, and broader renovation scopes planned around real lot and neighborhood dynamics.
This page is built for Irvine homeowners actively comparing detached ADUs, conversions, and broader property strategy.
This combination matters because many Costa Mesa owners are deciding between an ADU, a remodel, or a different way of improving the property entirely.
Everything you need to start planning your Accessory Dwelling Unit — zoning basics, cost ranges, and a step-by-step checklist.
Compare the costs, timelines, and benefits of building an ADU versus a traditional room addition for your property.
Instantly estimate your remodeling budget with our interactive calculator tailored to SoCal material and labor costs.
Everything Orange County homeowners need to know about building an ADU in 2026 — costs by type, permit timelines by city, state law preemptions, and how OC submarkets change every calculation.
Irvine ADU construction costs $150,000–$400,000+ in 2026. This guide covers the city’s streamlined permit process, HOA rules that cannot block your unit, UC Irvine rental demand, and real project scenarios from Woodbridge to Portola Springs.
Spring 2026 is the ideal season to break ground on your Costa Mesa ADU. Here is what to expect at every phase from design and permits through final inspection.