A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable ADU Builders Across Irvine
If you’re a homeowner in Irvine trying to figure out whether you can add a detached ADU, convert a garage, or build a JADU, the first thing to know is this: Irvine’s zoning rules are stricter than almost every city around you, and getting the plan check right the first time is what separates a 6-month project from a 14-month one. A properly permitted detached ADU in Irvine typically runs $180,000 to $320,000, depending on square footage, site conditions, and build method. We’ve been doing ADU work across Irvine long enough to know which lots in Northwood, Woodbridge, and Westpark will sail through plan check and which ones will need a setback variance. Call (361) 315-4177 for a written price before any work starts.
Fielding ADU Builders coordinates scheduling from our Los Angeles office, and our crews serve Irvine locally. We don’t hand you a “rough estimate” that drifts upward three weeks in. The price goes in writing before a single permit is pulled, and the Garrison Standard backs the finished work for 365 days.
Why Fielding ADU Builders Is Irvine’s Preferred ADU Builders Company
Irvine homeowners tend to ask sharper questions than most. This is a city full of engineers, planners, and people who read the fine print on HOA covenants. That suits us. We’re part of the Garrison Partners family, which has been building to The Garrison Standard since 2006: show up in the window, price in writing, by the book, leave it clean, stand behind it for a year. Reed Calloway leads the Fielding team, and every crew member on your Irvine job is background-checked and arrives in uniform. You’ll know exactly who is on your property and why.
We’ve completed detached ADUs in Woodbridge, University Park, and Quail Hill, and we know how strict the City of Irvine plan review desk can be. That local knowledge is the difference between a plan that passes on the first submittal and one that gets bounced back over a setback calculation. Our ADU Builders team handles the full start-to-finish scope: design coordination, permit drawings, foundation, utilities, framing or prefab panel installation, and final inspection. Ask for references from any Irvine neighborhood we’ve worked in. We’ll hand you real names and real addresses.
We answer the phone with a live person 24 hours a day, seven days a week. No voicemail tree. No callback queue. If you call at 11 p.m. to ask whether a 4-foot rear setback applies to your specific lot, a person answers.
Detached ADU in Irvine
A detached ADU in Irvine is a fully independent living unit, typically 450 to 1,000 square feet, built as a separate structure behind or beside the primary residence. Irvine’s zoning code requires a minimum 4-foot rear and side setback for detached ADUs and caps height at 16 feet on most single-family lots. That’s the single biggest pricing variable we see across the city, because it dictates whether your project clears plan check on the first submittal or requires a variance hearing.
Setback Compliance and Site Layout
In neighborhoods like Northwood and El Camino Real, the available buildable area shrinks fast once you subtract the 4-foot rear setback and the 4-foot side setback. We measure the lot before anything else. Then we tell you, in writing, what fits, what doesn’t, and whether a variance is worth pursuing. A variance adds time and money, and sometimes the smarter move is a smaller footprint or a JADU instead.
Foundation and Utility Trenching
A detached ADU needs its own foundation, and in Irvine, that usually means trenching from the street or the main dwelling for water, sewer, and electrical. Trenching costs run $40 to $90 per linear foot, and for a detached unit at the back of a deeper lot that can add $8,000 to $20,000 before you pour any concrete. We include this in the written price, up front, not as a surprise on the second invoice.
JADU in Irvine
A JADU in Irvine is a Junior Accessory Dwelling Unit, capped at 500 square feet, and Irvine requires it to be attached to the primary dwelling with an efficiency kitchen. This is different from Santa Ana and Tustin, which allow detached JADUs under some circumstances. In Irvine, a JADU is usually a garage conversion or a portion of the existing house converted into a separate living space with its own entrance.
Garage Conversion JADUs
The most common JADU we build in Irvine is a standard two-car garage conversion. Typical cost runs $80,000 to $140,000, depending on whether the slab needs leveling, how much electrical work the existing panel can handle, and whether the exterior wall needs a new window or door opening. Irvine plan check wants to see the efficiency kitchen specified clearly: a sink, a cooking appliance, a refrigerator, and storage. We spec that on the drawings the first time.
Attached JADU Additions
When a garage isn’t available, an attached JADU addition works. We extend the existing structure, usually 300 to 500 square feet, and build to the same 16-foot height limit as a detached ADU. This route typically runs $120,000 to $200,000, because it’s full conventional construction, not a conversion. The efficiency kitchen requirement applies here too. Irvine enforces it, and we build to it without arguing.
Trusted Brands We Service in Irvine
Some Irvine homeowners want a fully custom framed unit with James Hardie siding. Others ask about Abodu, Cover, or Dvele panels because they’ve seen the factories and like the timeline. We’re fluent in both. We work with major prefab and modular ADU platforms, including Abodu, Cover, Dvele, Mighty Buildings, Boxabl, and Plant Prefab, plus conventional construction. For a recent detached ADU in Woodbridge, we used a Plant Prefab panel system for a 600-square-foot unit with a full kitchen and bath. The project passed final inspection with no corrections, and the unit now serves as a rental for a local university student. We don’t push one brand over another. We price whatever method fits your lot, your budget, and Irvine’s plan review.
Common ADU Builders Problems We See in Irvine Homes
- Wrong setback assumptions. Homeowners or out-of-area contractors apply Santa Ana’s 3-foot setback to an Irvine lot and the plan check comes back rejected. That’s a redesign, a resubmittal fee, and four to six weeks lost.
- Underestimating plan review time. Irvine’s building department is thorough, and the plan review cycle for an ADU routinely runs six to ten weeks before approvals. If your contractor schedules excavation before the permit is issued, the schedule falls apart.
- Non-compliant prefab modules. Some prefab manufacturers sell units that don’t meet Irvine’s JADU attachment or kitchen requirements, or they exceed the 16-foot height limit. The unit arrives, then fails inspection.
- Utility pane upgrades done late. Many Irvine homes built in the 1970s and 1980s have 100-amp panels. An ADU with a full kitchen and laundry usually requires a 200-amp upgrade, and finding that out after framing starts adds $4,000 to $7,000 and resets the permit.
Pricing for ADU Builders in Irvine, CA
A garage conversion JADU in Irvine typically runs $80,000 to $140,000. An attached JADU addition lands between $120,000 and $200,000. A detached ADU of 600 to 800 square feet runs $180,000 to $320,000, with prefab panels on the lower end and full custom framing with James Hardie siding on the higher end. Permit fees, plan check fees, and utility connection charges add $8,000 to $15,000 depending on the project scope and site conditions. Everything goes in writing before work starts. The number you approve is the number on the final invoice. Call (361) 315-4177 for a free estimate with a written line-item price.
We Also Serve Cities Near Irvine
Our crews work across the surrounding area. We handle ADU projects in Tustin, Santa Ana, Orange, and Lake Forest, with the same written-price-first policy and one-year guarantee. If you’re just outside Irvine, call us and we’ll tell you what the local setback and height rules mean for your specific lot.
Serving Irvine, CA - Our Local Coverage Area
We’re based in the Irvine area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About ADU Builders in Irvine
Irvine requires a minimum 4-foot rear setback and 4-foot side setback for detached ADUs, with a maximum height of 16 feet on most single-family lots. Neighboring cities like Santa Ana and Tustin allow 3-foot setbacks, so if a contractor quotes you based on those rules, the plan will get rejected. Call (361) 315-4177 and we’ll measure your lot and tell you exactly what fits before you spend money on drawings.
Yes, Irvine permits JADUs up to 500 square feet, but they must be attached to the primary dwelling and include an efficiency kitchen with a sink, cooking appliance, refrigerator, and storage. Detached JADUs that neighboring cities allow are not permitted in Irvine. We spec the efficiency kitchen on the drawings from day one so plan check doesn’t bounce it back.
Plan review for an ADU in Irvine typically takes six to ten weeks, assuming the drawings are complete and compliant. Resubmittals add four to six weeks each. Projects that sail through on the first submittal usually do because the setbacks, height, and utility details were correct before the plans hit the city’s desk. Call (361) 315-4177 for a free estimate and we’ll map out a realistic schedule for your specific project.
The most frequent inspection failures we correct in Irvine are improper setback measurements, non-compliant prefab units that exceed the 16-foot height limit, and missing efficiency kitchen components in JADUs. A failed inspection costs you a rescheduling fee and two to three weeks of downtime. We’ve had recent Irvine projects pass final inspection with zero corrections, because the details were right before inspection day.
No, Irvine does not require a separate utility meter for an ADU, though some homeowners choose one for rental billing purposes. Most of our Irvine projects tie the ADU into the primary dwelling’s electrical panel, which means we upgrade the panel to 200 amps if the existing one can’t carry the additional load. Call (361) 315-4177 for an exact quote, and we’ll tell you whether your panel needs the upgrade before we write the price.
Written by Reed Calloway, Owner at Fielding ADU Builders, serving the greater Irvine area with ADU construction, garage conversions, and room additions.
