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 Commerce
Adding an ADU in Commerce usually means working with a small, fully built-out lot, an older detached garage, or a rear yard that backs up to an industrial corridor. Most of the projects we quote here fall between $180,000 and $320,000 for a complete detached unit, and a garage conversion typically lands between $120,000 and $210,000 depending on what the existing structure can actually support. We know Commerce’s building department runs its own plan check and inspection cycles, separate from LA County, and that changes how your project gets scheduled. Call (472) 248-8213 and we’ll walk you through what your specific lot can realistically hold.
Why Sutton ADU Builders Is Commerce’s Preferred ADU Builders Company
Commerce homeowners call us because we hand them a written price before a single tool shows up, and because we send the name and photo of every technician who will walk onto the property before they arrive. That matters here more than most places. Commerce is a small city, just over 6.5 square miles, with homes mixed directly into industrial blocks. You can’t always see who’s parked out front. Our Threshold Verified standard means every crew member is background-checked, identity-verified, and photo-badged. We send you who’s coming, you see the badge at the door, and the 365-Day Done Right Promise covers workmanship for a full calendar year after completion.
We’ve quoted projects near Bristow Park, worked through plan check for lots off South Atlantic Avenue, and sorted out garage conversions where the slab wasn’t level and the electrical panel needed a full replacement before framing could even start. That local repsonse time is real: our scheduling for Commerce runs through the Los Angeles office, but crews work this city directly and know the counter staff at Commerce City Hall.
ADU Contractor in Commerce
An ADU Contractor in Commerce is the licensed builder who carries your project from initial lot assessment through plan check, foundation work, framing, mechanical rough-in, and final inspection with the City of Commerce building department. You need one when you’re adding livable square footage to a property that already has a house on it, whether that’s a rear-yard detached unit, a garage conversion, or an attached addition. Most homeowner calls to us start with a simple question: can my lot even do this? We answer that with a site visit, not a phone guess. Expect $180,000 to $320,000 for a new detached ADU, and $120,000 to $210,000 for a conversion depending on what’s salvageable.
Garage Conversion Scope Checks
Commerce has a lot of detached garages built between 1940 and 1970. Many were never engineered for living space. Before we quote, we look at the slab thickness, roof structure, and electrical service. A garage with a 3-inch slab, no footing, and a 60-amp panel is not a cheap conversion. It’s a teardown and rebuild inside the same footprint. We’ll tell you which one you have.
New Detached Build Sequencing
For a new rear-yard ADU, the order in Commerce goes like this: property survey, site plan submittal, plan check through the city’s building department, corrections if the plan checker flags anything, then permits issued and construction starts. Setbacks matter. Commerce enforces its own zoning code, and because so many lots are narrow or adjacent to commercial uses, the planning counter often wants a parking plan and a fire access note before they’ll stamp your drawings.
ADU Design in Commerce
ADU Design in Commerce means producing a plan set that survives plan check with the city’s own building department, not a generic package that assumes LA County rules. You need it before you can pull a permit, and small mistakes in it cost weeks. We draw or coordinate site plans, floor plans, structural details, Title 24 energy compliance, and egress window sizing. Plan check fees in Commerce are separate from construction fees, and correction cycles here run on the city’s schedule, not the county’s. Budget $8,000 to $25,000 for full design and permitting on a typical Commerce ADU, and expect two to four months from first submittal to issued permit depending on how clean the first plan set is.
Prefab and Modular Plan Integration
When a homeowner wants a prefab unit from Cover, Dvele, or Boxabl, the design phase shifts. The factory handles the box, but we handle the site plan, foundation design, utility trenching, and the permit package that the city reviews. A prefab ADU is not a shortcut past Commerce plan check. The city still reviews the site work, the foundation, the utility connections, and the energy compliance. We’ve shepherded plenty of these through and know what gets flagged.
Site Constraints on Design
Commerce lots tend to be modest. A design that works in Riverside or Anaheim may not fit on a 5,000-square-foot lot off Eastern Avenue. Setbacks, easements, and access for a concrete truck and crane all shape the floor plan. We design to the lot’s actual dimensions, not to an idealized rendering. That’s the difference between a plan that gets approved and one that bounces back to you with a redline letter.
Trusted Brands We Service in Commerce
We install and service ADU Builders product lines from Cover, Dvele, and Boxabl, and we integrate James Hardie cladding systems where the exterior needs to match an existing Commerce house. Local inventory moves through our Los Angeles coordination, so Commerce customers aren’t waiting on a factory in another state for common components. If you’re weighing a prefab path against a stick-built build on your lot, we’ll give you an honest read on which of these brands actually fits your site, your budget, and the city’s plan check process. We don’t have a favorite box. We have a favorite outcome: a permit that clears and a structure that lasts.
Common ADU Builders Problems We See in Commerce Homes
- Out-of-level garage slabs. Many detached garages in Commerce were poured as parking pads, not foundations. We regularly find 2 to 4 inches of fall across the slab, which means a conversion requires a new thickened-edge slab or full demolition and repour before framing can start.
- Undersized electrical services. Older Commerce homes frequently run 60-amp or 100-amp panels. Adding an ADU with a kitchen, mini-split, and laundry pushes that beyond code. A new subpanel or a full service upgrade from Southern California Edison adds cost and schedule time up front.
- Setback and parking friction. Because Commerce mixes residential and industrial zoning so tightly, the planning counter often requires a parking replacement plan if your garage conversion removes an existing covered space. We handle that in the plan set, but it’s a local wrinkle generic builders miss.
- Plan check assumptions from LA County. Homeowners who’ve done work elsewhere assume the permit path runs through Los Angeles. It doesn’t. Commerce has its own building department, its own correction cycles, and its own inspectors. Treating it like an LA city job causes missed deadlines and resubmission fees.
Pricing for ADU Builders in Commerce, CA
We give written prices, not ballparks. A detached ADU in Commerce typically runs $180,000 to $320,000 complete, with the spread driven by foundation conditions, utility trenching distance, finishing level, and whether you choose a prefab route or stick-built. Garage conversions land between $120,000 and $210,000 depending on whether the existing structure can be saved. Design and permitting add $8,000 to $25,000. Site work, which includes slab prep, trenching, and utility connections, is its own line item and usually runs $15,000 to $45,000 here because of the older lots. We don’t lock a price without walking the property. Call (472) 248-8213 for a free estimate and we’ll put real numbers on your specific lot.
We Also Serve Cities Near Commerce
Beyond Commerce, our crews cover ADU Builders in Commerce and the surrounding cities. That includes Los Angeles, Long Beach, Anaheim, and Riverside. If your property sits on the edge of Commerce or in a bordering neighborhood, call us and we’ll confirm coverage and scheduling for your address.
Serving Commerce, CA - Our Local Coverage Area
We’re based in the Commerce 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 Commerce
The City of Commerce handles its own ADU permits. Commerce has operated its own building department since incorporation in 1960, so your plan set, plan check corrections, inspections, and final sign-off all run through Commerce City Hall, not through LA County. Expect the city’s review schedule, not the county’s. Call (472) 248-8213 and we’ll give you a realistic timeline for your project.
You can convert a detached garage in Commerce into an ADU, but whether it’s worth converting depends on what’s actually there. Older Commerce garages often have no foundation, no insulation, and insufficient electrical service, which means the conversion cost can approach a new build. We’ll inspect the slab, roof framing, and panel before recommending a scope. Call (472) 248-8213 and we’ll tell you if your garage is a keeper.
Foundation condition, utility trenching distance, finishing level, and whether you choose prefab or stick-built are the four biggest cost drivers in Commerce. Older lots mean more excavation risk and more electrical upgrade work. Finishes move the needle too: builder-grade finishes versus custom cabinetry and quartz can swing the total by $40,000 or more. For an exact quote, call (472) 248-8213 for a free estimate.
Expect five to eight months from first call to final inspection for a detached ADU in Commerce, including design, plan check, and construction. Plan check alone typically runs two to four months with the city’s own building department. A garage conversion can move faster if the structure is sound. We’ll give you a written schedule with your written price. Call (472) 248-8213 to start the clock.
The only price changes on our projects come from conditions we couldn’t see before opening walls or excavating: unexpected buried utilities, rotted framing under stucco, or a slab that crumbles during demo. We document every change in writing before proceeding, and our written estimate already accounts for the common Commerce conditions we see regularly. If you want a builder who doesn’t hand you surprise invoices, call (472) 248-8213.
Written by Miles Hartwell, Owner at Sutton ADU Builders, serving Commerce and surrounding cities.
