ADU Company in Ontario — Design, Permits and Build Under One Contract

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ADU Company in Ontario, CA

Kitchen remodeling in Ontario usually means reworking a 1960s-to-1980s tract home kitchen inside a single-story stucco house where the original footprint was never designed for modern appliances, island seating, or the way families actually cook now. The heat is the other driver: Ontario summers routinely push past 100°F, so ventilation, range-hood sizing, and window placement aren’t aesthetic choices here, they’re how you keep a kitchen usable from June through September. Classic ADU Builders handles kitchen remodeling as part of our broader ADU and remodeling work across Ontario, from downtown bungalows to the deep-lot tracts in 91761, 91762, and 91764. Call (877) 265-5587 for a free estimate on your Ontario kitchen.

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Why Ontario Homes Are Different

Ontario’s housing stock is dominated by mid-century and 1960s-80s single-story stucco tract homes with attached two-car garages and deep rear yards, plus a band of older pre-war bungalows near downtown. That matters for kitchen work because these original kitchens were built tight and closed-off, with load-bearing walls separating them from the living space and electrical panels that were sized for a different era. Many Ontario homes still run on 100-amp panels, and when a kitchen remodel adds a second oven, a microwave circuit, and under-cabinet lighting, the panel often needs upgrading before the fun part starts.

The climate shapes material choices too. Ontario sits in the hot, smoggy western San Bernardino Valley, where summer highs regularly cross 100°F with low humidity and intense sun, and winter mornings can dip near freezing. That swing means cabinet finishes, flooring, and countertop adhesives need to handle real temperature expansion and contraction, not the mild-coastal assumption. We also plan ventilation around how Ontario homeowners actually live: windows that open in the evening to catch the cooling air, hoods that actually exhaust outside rather than recirculating hot air back into a 100-degree kitchen.

Permitting runs through the City of Ontario’s building department, and the typical kitchen remodel that moves walls or changes the electrical layout will need plans, permits, and inspections. The process is straightforward for a contractor who has done it repeatedly, but the paperwork is real and it adds time. We pull permits on every Ontario kitchen remodel and walk the inspections through to sign-off.

Our Main Ontario Services

Most Ontario homeowners reach out to us for one of two things: building an ADU on their deep rear lot or converting a garage, and remodeling a bathroom that’s still original to a 1970s tract home. Here’s what each involves in Ontario specifically.

ADU Builders in Ontario

Ontario is one of the Inland Empire’s strongest ADU markets because the lot sizes in 91761, 91762, and 91764 are deep enough for a detached rear-yard unit, and many attached garages open onto alleys or side yards that make conversion practical. The catch we see most often is the existing electrical: many of these mid-century homes have 100-amp panels that can’t carry a second dwelling unit, so panel upgrades become part of the ADU scope. We work with prefab systems from Boxabl and Plant Prefab, do Tuff Shed conversions for budget-conscious rentals, and build custom site-built ADUs when the lot calls for it. For the full picture on detached units, garage conversions, and local Ontario ADU costs, see our ADU Builders in Ontario page.

ADU Builders in Ontario

Bathroom Remodeling in Ontario

Bathroom remodels in Ontario’s tract homes run into the same legacy issues as kitchens: original cast-iron plumbing that has seen 50 years of hard water, small footprints, and ventilation that was never up to the job. In the older pre-war bungalows near downtown, bathrooms are often tiny by modern standards and need creative layouts to fit a real shower and storage without moving exterior walls. Ontario’s hard water also means we recommend fixtures and finishes that resist mineral buildup rather than whatever looks good in a showroom. For specifics on cost, timeline, and the Ontario bathroom permit process, visit our Bathroom Remodeling in Ontario page.

Bathroom Remodeling in Ontario
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What happens when you call

  1. 1
    A real person answersNo phone trees — you reach a local pro.
  2. 2
    You get an upfront price rangeHonest numbers before anyone is dispatched.
  3. 3
    A background-checked tech heads outLicensed & insured, dispatched right away.
  4. 4
    You approve before work beginsNothing starts until you say go.

Kitchen Remodeling in Ontario

Kitchen remodeling in Ontario is usually about opening up a closed-off 1960s-to-1980s kitchen inside a single-story tract home, replacing original cabinets and laminate counters, and bringing the electrical and ventilation up to a standard that handles both modern appliances and Ontario’s triple-digit summer heat. A kitchen that stays cool and breathable in August takes planning, not just prettier cabinets, and that’s where our Ontario experience matters. As a full-service remodeling contractor, we handle everything from the first demolition cut to the final outlet cover, and we also build the Kitchen Remodeling work into larger ADU projects when the unit needs a finished, rentable kitchen.

Cabinet Replacement

Signs you need it

Cabinet doors are delaminating, drawer slides are failing, or the layout wastes the kitchen’s footprint and you’re fighting the space every time you cook.

What it costs in Ontario

A full cabinet replacement in an Ontario tract kitchen typically runs $12,000 to $35,000 depending on whether you’re doing stock boxes or semi-custom with soft-close hardware.

How we do it

We measure the full kitchen, order the cabinet run to the inch, disconnect and remove the old boxes, patch the walls, then install new cabinets, level and shim every run, and hang doors and drawers with soft-close hardware adjusted tight.

Countertop and Island Work

Signs you need it

Your original laminate counters are burned, chipped, or separating at the seams, or you want to add an island but the current layout doesn’t have a clear path to run power and plumbing.

What it costs in Ontario

New countertops in an Ontario kitchen typically run $4,000 to $12,000 including fabrication and install, with an added island pushing $3,000 to $8,000 depending on size and whether it needs electrical.

How we do it

We template the existing cabinets for exact fit, order the slab or quartz, cut and polish the edges off-site to keep dust out of your house, then set the counter, seam it, and wire any island outlets to code.

What Kitchen Remodeling Costs in Ontario

Item Typical range in Ontario
Full kitchen remodel (mid-sized) $30,000 – $75,000
Cabinet replacement $12,000 – $35,000
Countertops and island $4,000 – $12,000

Two things push kitchen remodel prices up in Ontario: panel upgrades on older 100-amp homes, and structural work when you open a load-bearing wall between the kitchen and living room. We give you a written, line-item quote before work starts and we don’t change the price mid-job unless you change the scope.

How long does a kitchen remodel take in Ontario?

A full Ontario kitchen remodel runs 6 to 10 weeks from the first demo day to final inspection, depending on cabinet lead times and whether the panel needs upgrading. Call (877) 265-5587 for a timeline tied to your specific kitchen.

Will my kitchen remodel need a permit in Ontario?

Yes, any Ontario kitchen remodel that moves walls, changes the electrical, or alters plumbing requires a permit from the city’s building department, and we pull it and close it out for you. Call (877) 265-5587 to confirm what your scope needs.

Brands We Service in Ontario

We work across the brands Ontario homeowners are already researching, including Boxabl and Plant Prefab for modular ADUs and Tuff Shed for the most budget-conscious permitted conversions. Our crews are also experienced with James Hardie fiber cement exteriors, which hold up to Ontario’s sun and heat without fading or warping the way vinyl does. See our brands for the full breakdown of what we work with and why.

Pricing for ADU Company in Ontario, CA

Service Typical range in Ontario
Full kitchen remodel (mid-sized tract home) $30,000 – $75,000
Cabinet replacement $12,000 – $35,000
Countertops and island $4,000 – $12,000
Bathroom remodel (full) $18,000 – $45,000
ADU – prefab or modular (turnkey) $180,000 – $350,000
ADU – garage conversion $120,000 – $250,000
ADU – Tuff Shed conversion (permitted) $80,000 – $180,000
ADU – custom site-built $250,000 – $600,000

What pushes a project toward the high end in Ontario is usually the existing panel and the condition of the utility runs: 100-amp electrical upgrades, old cast-iron drain lines, and undersized gas lines all add real cost before the visible work begins. We give every Ontario homeowner a fixed, written quote up front, and we honor it unless you add scope.

Neighborhoods We Serve in Ontario

We work throughout Ontario, from the pre-war bungalows near downtown to the mid-century tracts that fill out the rest of the city. Most of our kitchen and ADU work in Ontario concentrates in the deep-lot neighborhoods where garage conversions and rear-yard units make the most sense.

  • Downtown Ontario (historic bungalows)
  • North Ontario (91761 and 91764 tracts)
  • West Ontario (91762)
  • South Ontario (near the 60 corridor)
  • East Ontario (toward the 15 and Airport)

We typically start Ontario estimates within a week of your call, and we schedule projects based on your timeline, not ours. If you’re in Ontario and ready for a kitchen, bathroom, or ADU estimate, call (877) 265-5587.

Service Area – Cities Near Ontario

Classic ADU Builders serves Ontario and the surrounding Inland Empire cities, including Montclair, CA to the west, Upland, CA to the north, Chino, CA to the south, and San Antonio Heights, CA to the northwest. The housing stock and climate are similar across these cities, so our Ontario pricing and approach applies with minor adjustments for local permit departments.

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

Ready to get started? Free estimates · Free written quotes response in Ontario
Call (877) 265-5587

What happens when you call

  1. 1
    A real person answersNo phone trees — talk to a local adu pro.
  2. 2
    You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
  3. 3
    We come out and measureLicensed & insured, at a time that suits you — the visit and the quote are both free.
  4. 4
    You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.

What Ontario Customers Say

★★★★★ 4.8 from 4+ reviews

"Garage conversion to a one bedroom unit. He handled the plans, the city submittal, and every round of corrections. Took six months from first meeting to final inspection and he never once made the permit process my problem."

— Beatriz Morales

"The kitchenette layout he suggested made better use of the space than the one on our original sketch."

— Eric Tran

"Detached unit in the back yard. Utilities trenched, separate meter, and it passed final on the first inspection."

— Steve Mercer

How It Works in Ontario

Getting your adu handled is simple and fast.

1

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2

Licensed Technician Dispatched

A background-checked, certified technician arrives in Ontario — typically within 30–60 minutes, with parts stocked on the truck.

3

Problem Solved, Guaranteed

We complete the job to your full satisfaction, backed by our warranty and 100% satisfaction guarantee.

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