A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Orange, CA
Fielding ADU Orange County builds accessory dwelling units, garage conversions, and room additions throughout Orange, CA. We’re the ADU and room-addition specialist inside the Garrison Partners family, and we hold every Orange job to The Garrison Standard: a written price before any work starts, permitted work done by the book, and a full year of written guarantee on what we build. If you’re planning an ADU in Orange, call (424) 577-4306 and we’ll give you a straight answer on cost and feasibility.
Why Orange Homes Are Different
Orange isn’t a cookie-cutter suburb. The housing stock spans early-1900s Craftsman and Spanish Colonial Revival homes in Old Towne to mid-century ranch and tract houses built through the 1950s, 60s, and 70s. That mix matters when you’re planning an addition or ADU. A 1920s Craftsman on a large Old Towne lot has different foundation realities than a 1965 tract home in the eastern neighborhoods. Older Orange homes often have detached garages that look like easy ADU conversions, but retrofitting them means real work on the foundation, the electrical panel, and the plumbing supply lines. You can’t just sheetrock over a 1940s garage slab and call it done.
Orange is also a charter city, which means it operates under its own building codes rather than the standard California codebook that surrounding jurisdictions use. In practice, that affects permitting timelines and specific requirements. You want a contractor who’s already familiar with Orange’s plan check process, because a surprise at the permit counter is a delay you don’t need. Add in the city’s Design Review Committee process for properties inside the Old Towne Orange Historic District, and you start to see why Orange ADU projects benefit from local experience: those plans need to match the neighborhood’s early-1900s character, which often means custom detailing that a generic builder won’t anticipate.
The climate shapes the build, too. Orange summers are hot and dry, which means insulation and ventilation choices that keep an ADU cool without running the AC constantly. We spec for that heat. The winters are mild and wet, and we build for drainage and moisture control. Unlike coastal cities, salt-air corrosion isn’t a concern here, but the sun is punishing on roofing and stucco, and occasional Santa Ana winds test every exterior finish. We pick materials accordingly.
Our Main Orange Services
Most Orange homeowners call us about one of three things: adding a room to the main house, converting a detached garage into living space, or building a backyard ADU from the ground up. Each has its own page with the full pricing detail for Orange.
Room Addition Contractor in Orange
Room additions in Orange often mean expanding a mid-century ranch that was built for a smaller household. We handle the foundation, framing, roofing, electrical, and finish work as one permitted project. On older Orange lots, setback requirements and lot coverage limits shape how much you can add, and as a charter city Orange enforces its own version of those rules. You’ll get a written line-item price before we start. Full detail is on the Room Addition Contractor in Orange page.
Garage Conversion Contractor in Orange
Many Orange homes, especially in the older neighborhoods, have detached garages that are underused as storage and ideal for conversion. The catch is that a 1940s or 1950s garage usually needs a new foundation edge, panel upgrade, and plumbing run before it becomes legal living space. We price that work honestly and put the full number in writing. See the Garage Conversion Contractor in Orange page for Orange-specific conversion costs.
ADU Builders in Orange
Orange’s large lots and rear-alley access in older neighborhoods make detached ADUs realistic here in a way that denser nearby cities can’t match. That alley access means we can often stage a prefab or modular ADU delivery without tearing up the front yard. We build conventional ADUs and work with major prefab platforms like Dvele, Mighty Buildings, and Boxabl, so we can match the method to your lot and budget. Pricing detail is on the ADU Builders in Orange page.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Brands We Service in Orange
We’re fluent with the prefab and modular ADU platforms Orange homeowners are already researching, including Dvele and Mighty Buildings, and we build conventionally with materials like James Hardie siding. If you’re weighing a prefab ADU against a stick-built one, call us and we’ll walk through the trade-offs for your specific Orange lot. See our brands for the full picture.
Pricing for ADU Company in Orange, CA
| Service | Typical range in Orange |
|---|---|
| Detached ADU (conventional build) | $180,000 – $320,000 |
| Detached ADU (prefab/modular) | $140,000 – $260,000 |
| Garage conversion ADU | $90,000 – $180,000 |
| Attached ADU (junior ADU) | $80,000 – $150,000 |
| Room addition (single room, 200 – 400 sq ft) | $60,000 – $140,000 |
| Room addition (primary suite with bath) | $90,000 – $200,000 |
| Room addition (second story) | $150,000 – $300,000+ |
| Foundation upgrade on older garage conversion | $8,000 – $30,000 |
| Electrical panel upgrade (100A to 200A) | $3,000 – $6,500 |
| Full kitchen in ADU | $20,000 – $45,000 |
What pushes a price up in Orange specifically? Historic District design review, rear-alley delivery complications, and the foundation and panel work that older Orange garages almost always need. But the number we put in writing before any work starts is the number you pay on the final invoice. No change orders at the door.
Neighborhoods We Serve in Orange
We work across Orange, from the historic streets of Old Towne to the ranch and tract neighborhoods east of the 55. Our crews are in Orange throughout the week, and we schedule estimates within a few days of your call.
- Old Towne Orange Historic District
- El Modena
- Orange Park Acres
- Mabury Park
- Presidential Streets neighborhood
Service Area – Cities Near Orange
Fielding ADU Orange County is based in the Orange area and serves homeowners across central Orange County. If your project is outside the Orange city line, we also work in Santa Ana, CA, Tustin, CA, Garden Grove, CA, and Fountain Valley, CA. Call us and we’ll confirm coverage for your address.
Serving Orange, CA - Our Local Coverage Area
We’re based in the Orange 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 Company in Orange
We schedule estimates within a few days of your call, and once you approve the written price, we pull the permit and start on the next available crew window. Orange is a charter city with its own plan check process, so permit timelines vary. Call (424) 577-4306 for a realistic start date on your project.
Only if your property is inside the Old Towne Orange Historic District. Those projects need Design Review Committee sign-off on the exterior to match the neighborhood’s early-1900s character, which can add weeks and custom detailing cost. Most Orange properties outside that district do not need that step.
Yes. Permitted work done by the book is part of The Garrison Standard. We prepare the drawings, file with the city of Orange, pull the permit, and schedule inspections. You don’t chase paperwork. If the work fails inside the one-year written guarantee, we return and correct it at no charge.
Planning an ADU, garage conversion, or room addition in Orange? Call Fielding ADU Orange County at (424) 577-4306 for a free estimate and a written price before any work starts.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What Orange Customers Say
"Good addition. Electrical inspection delayed a week, which was the county, but the build is great."
- Eva K."Room addition over the back patio. Framing is square, windows are tight, and the roofline matches."
- Danny L."Garage conversion with a new bath and kitchenette. Permit was handled by them. Inspection passed first time."
- Sheila B.
