ADU Company in Ontario, CA
Lodgewick ADU Builders handles accessory dwelling units, garage conversions, and home additions across Ontario, with pricing shaped by this city’s specific housing stock and climate. Most of Ontario’s homes are 1950s – 1970s ranch-style tract houses on 7,000 – 10,000 sq ft lots, which means garage-conversion JADUs and rear-yard detached units are almost always feasible. The heat is the biggest wildcard here: summers routinely hit 105 – 110°F, so HVAC sizing on an Ontario ADU isn’t a guess, it’s a calculation. Call (254) 602-5618 for a written estimate.
Why Ontario Homes Are Different
Ontario sits at the center of one of North America’s densest warehouse and logistics corridors, the I-10/Ontario Airport industrial belt. That geography does something unusual to the ADU market: homeowners in the residential tracts next to those distribution centers can often command steady monthly rent from workers who need to live close to shift jobs but get priced out of standard apartments. A 600-sq-ft detached ADU in the neighborhoods between Archibald and Vineyard regularly rents for more than the same unit would in Rancho Cucamonga, Claremont, or Upland. That changes the math on payback time, and it changes how we think about a project before the first plan is drawn.
The housing stock matters just as much. Older blocks near Historic Downtown Ontario include parcels platted during the citrus-era subdivisions, some larger than the typical Inland Empire tract and able to fit a detached ADU with room left over. Most of the city, though, is 1950s and 1960s ranch construction with attached two-car garages, and those garages are built on slabs that usually pass inspection for a conversion as long as the roof structure hasn’t sagged. Summer heat is the constant variable: mini-split systems specced for coastal temperatures run constantly and still fail to hold 78°F inside a detached ADU during a Santa Ana event. Any Ontario job should account for a high-static ductless unit and extra insulation in the attic plane.
Our Main Ontario Services
Ontario homeowners call us most often for two things: converting an existing garage into living space, or adding a detached ADU to the rear yard. Here’s what each involves here.
Home Addition Contractor in Ontario
A home addition in Ontario means expanding the footprint of the house itself, usually out the back or over the garage, and it has to account for the city’s lot-size rules and the summer heat load on any new roofline. We size new ducts and insulation for 105°F days, pull the permits, and give you a written price before the job starts. Because Ontario’s ranch tracts have predictable setbacks, many additions can go wider than homeowners assume. Find the specifics on our Home Addition Contractor in Ontario page, including real price ranges.
Garage Conversion Contractor in Ontario
A garage conversion turns an attached two-car garage into a permitted JADU or a full ADU, and in Ontario the attached-garage ranch layout makes this one of the fastest ways to add livable square footage. The concrete slab is usually sound, the electrical panel is close by, and the roof line often needs only minor tie-in work. We check door-header framing, moisture through the slab, and whether the garage’s original footings meet current code before we quote the number in writing. See the full scope and Ontario-specific costs on our Garage Conversion Contractor in Ontario page.
ADU Builders in Ontario
Building a detached ADU in Ontario means designing for 110°F summer days, dry UV-heavy air that shortens exterior material life, and a lot that’s typically between 7,000 and 10,000 sq ft. We work frequently with Abodu and Cover prefab shells on these rear-lot builds because their framing arrives quickly and their envelope performs well in sustained heat, matched to the site by our own foundation and finish crew. The full Ontario ADU pricing and process breakdown lives on our ADU Builders in Ontario 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 Ontario
We install and finish ADUs from Abodu, Cover, and Dvele, and we work with Mighty Buildings on specific panelized designs. Prefab shells get here fast; the schedule depends on your lot’s foundation and utility runs. Details on all of them are on our brands page.
Pricing for ADU Company in Ontario, CA
| Service | Typical range in Ontario |
|---|---|
| Detached ADU (construction only) | $185 – $310 per sq ft |
| Detached ADU (full build, mid-range finishes) | $318,000 – $442,000 |
| Prefab ADU (total installed cost) | $245,000 – $360,000 |
| Garage conversion to JADU (fully finished) | $92,000 – $157,000 |
| Garage conversion to ADU (full build out) | $135,000 – $205,000 |
| Home addition (up to 2,000 sq ft) | $92,500 – $280,000 |
| Bathroom addition | $34,500 – $52,500 |
| Bedroom addition | $27,500 – $42,500 |
| Loft conversion | $45,000 – $90,000 |
In Ontario, two things push a price higher than the base range: high-static HVAC sized for 105°F days, and deeper foundation work when a garage slab or rear-yard soil doesn’t meet current bearing standards. Whatever the number, you get it in writing before any work begins, and it doesn’t change at the door.
Neighborhoods We Serve in Ontario
We work across Ontario’s residential tracts, from the older citrus-era blocks near Historic Downtown to the newer subdivisions south of the 60. Most areas are within a short scheduling window for estimates, and our crews are on job sites across the city every week.
- Historic Downtown Ontario
- North Ontario (near I-10)
- South Ontario (near the 60)
- Archibald Ranch
- Ontario Ranch
Service Area – Cities Near Ontario
If you’re just outside Ontario city limits, we also cover the surrounding cities in the western Inland Empire. Homeowners in Montclair, CA, Claremont, CA, Upland, CA, and Rancho Cucamonga, CA can schedule through the same office and receive the same written-price guarantee.
Serving Ontario, CA - Our Local Coverage Area
We’re based in the Ontario 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 Ontario
We schedule Ontario estimates on a rolling weekly basis, and depending on the season you’ll usually have an appointment within a few business days. The written estimate itself is prepared after the site visit, not given over the phone.
Parts of Ontario fall within Ontario International Airport’s approach corridor, which means the FAA imposes height advisory zones that can add a verification step before the city issues a permit. We check whether your parcel is affected early, before you spend money on plans.
Yes, that’s the single biggest local factor. Ontario’s sustained summer temperatures demand HVAC units and insulation designed for the Inland Empire, not coastal California. Our pricing assumes the right equipment from the start, and it’s why we size every unit to the actual lot, not a generic square-footage chart.
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 Ontario Customers Say
"Garage conversion into a studio for our teenager. Honest about what was realistic and what wasn't, finished close to schedule, and cleaned up the site daily."
- Marcus Beaumont"I was nervous about adding on but they walked me through every step and every cost before we started. No surprise change orders halfway through like I'd heard horror stories about."
- Eleanor Pratt"Junior ADU conversion inside the house. They protected the rest of our place with plastic and daily cleanup. Done nearly on schedule and on the number they quoted."
- Sabrina Veld