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
An ADU in Commerce typically runs $180,000 to $380,000 for a detached unit, with prefab options starting around $150,000 and custom site-built projects reaching $450,000 or more. Most Commerce builds take six to nine months from permit submittal to final inspection, though your specific lot and floor plan drive that timeline. We work across Commerce from Bandini to the Citadel area, and we know the difference between what Commerce’s planning counter wants and what a contractor from another city assumes. Call (903) 568-7222 and we’ll walk you through what your property can actually support before you spend a dime.
Why Benson ADU Builders Is Commerce’s Preferred ADU Builders Company
Commerce homeowners keep hiring us for one reason that matters more than anything else: we put the full price in writing before any work starts, and that price doesn’t shift unless you change the scope. No verbal ballparks, no “we’ll figure it out as we go.” Our ADU Builders team knows Commerce’s municipal code inside out, which matters here more than in neighboring cities because Commerce runs its own building counter. A contractor who quotes Commerce work assuming LA city rules will get the setback and lot-coverage math wrong. We don’t.
Every crew we send into Commerce is background-checked and arrives in uniform, so you always know exactly who’s on your property. Your project gets a live project tracker you can check from your phone, with before-and-after photos and digital invoices payable by link. That’s the kind of transparency Troy Eastman built this company around: a written guarantee stamped on every single job, and a 365-Day Done Right Promise that means if something’s not right a year later, we fix it. A live person answers our phone around the clock, so you’re never waiting until Monday to talk to a human.
Backyard ADU in Commerce
A Backyard ADU in Commerce is a detached accessory dwelling unit built in the rear yard of a single-family lot, and on this city’s flat, postwar parcels that usually means a slab-on-grade build anywhere from 500 to 1,000 square feet. A homeowner on W Slauson Ave near Commerce Blvd wanted exactly that behind their 1950s ranch house, so our crew framed a 700-square-foot unit with James Hardie cladding after confirming the rear setback against Commerce’s municipal code. We pulled the building, electrical, and plumbing permits through Commerce Building & Safety, passed framing and final inspections, and handed the keys over in about six months. For this size yard, you’re looking at $190,000 to $300,000 for a quality site-built unit.
Site-Built vs. Prefab
Commerce’s older lots often have tight side yards, which changes what’s deliverable. Boxabl and Cover panels were quoted as options on that Slauson Ave project, but the side-yard access was too narrow for a prefab crane. Site-built framing worked because we could hand-carry materials through a four-foot gate. On wider lots, prefab cuts weeks off the schedule.
Setbacks and Lot Coverage
Commerce enforces its own setback and lot-coverage rules, and they’re not the same as LA city’s. A 500-square-foot ADU might fit under LA’s standards but blow past Commerce’s coverage limit on a 5,000-square-foot lot. We check this against Commerce’s municipal code before we ever quote a price, because a permit-ready number that ignores local rules is worthless.
ADU Construction in Commerce
ADU Construction in Commerce means taking a unit from bare dirt through plan check, foundation, framing, mechanicals, and final inspection, and the city’s own timeline sets the pace far more than weather ever does. Commerce runs its own building counter, so there’s no LA city LADBS plan check to lean on. Expect a two-to-three-week plan-check lag at Commerce Building & Safety, and assume your start date shifts accordingly. For a complete site-built ADU in Commerce, budget $220,000 to $380,000 depending on square footage, finishes, and whether you’re adding a second story or keeping it single-level.
Permits and Inspections
We pull building, electrical, and plumbing permits through the Commerce counter directly, and we schedule every inspection the city requires. Framing, rough electrical, final: all of it. Passing these on the first pass keeps your calendar intact, and our team knows what Commerce inspectors look for.
The Fixed-Price Contract
Before we break ground, you get a written line-item price that covers labor, materials, permits, and site prep. Change orders are rare and only happen when you ask for something new. The 365-Day Done Right Promise stays with you even after we pack up.
Trusted Brands We Service in Commerce
We install and finish ADUs from Cover, Dvele, and Boxabl, and we stock the common mounting hardware and trim pieces those units need so Commerce customers aren’t waiting on a backordered part from out of state. If you’ve already researched these brands, you know what they cost and what they deliver. We handle the local side: the permitting, the site work, the utility connections, and the finish details that make a prefab unit look like it grew out of the ground. Fast turnaround on brand-specific repairs and adjustments, too, because we’re already working with these products on Commerce lots every month.
Common ADU Builders Problems We See in Commerce Homes
- Quoting before checking Commerce’s own code. A price that assumes LA city setbacks will be wrong on day one. We verify your rear-yard setback and lot coverage against Commerce’s municipal rules before we quote.
- Promising a calendar built on LA’s plan-check queue. Commerce’s counter moves on its own schedule, and that two-to-three-week lag doesn’t exist in other nearby cities. Any builder promising a start date without confirming Commerce’s current queue is guessing.
- Ordering a prefab kit that won’t fit the side yard. Boxabl, Cover, and Mighty Buildings units need crane and staging access, and Commerce’s older lots often have gate widths under five feet. We check utility trench depth and staging access before recommending a panelized build.
- Underestimating slab and soil prep on postwar lots. Many Commerce homes sit on compacted fill that needs extra prep before a slab pour. Skipping this step cracks that new ADU floor within a few seasons.
Pricing for ADU Builders in Commerce, CA
Here’s the honest math for Commerce, not a national average. A prefab studio ADU from Boxabl or Cover runs $150,000 to $220,000 installed. A site-built one-bedroom backyard ADU lands between $190,000 and $300,000. A custom two-bedroom with a full kitchen and laundry pushes $320,000 to $450,000 depending on finish level. What moves the price here specifically: lot coverage limits that force smaller footprints, soil conditions on older fill, and the extra care narrow side yards require. Every estimate we give is written, line-itemed, and fixed before we start. Call (903) 568-7222 for your free estimate.
We Also Serve Cities Near Commerce
Our crews handle ADU projects throughout the area and regularly work with homeowners in Los Angeles, Long Beach, Anaheim, and Riverside. If you’re just outside Commerce, we still bring the same fixed-price contract and 365-Day Done Right Promise. Learn more about how we serve the wider region as ADU Builders in Commerce and nearby communities.
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
You go through Commerce’s own Building & Safety counter, not LA city’s LADBS and not the county. Commerce runs its plan check and inspection scheduling independently, which is why the process here moves on a Commerce-specific timeline. Call (903) 568-7222 and we’ll tell you exactly what the current queue looks like before you commit to a start date.
Lot coverage limits, soil conditions, and side-yard access drive Commerce pricing more than anything else. A slab on compacted postwar fill costs more to prep than virgin dirt. A tight gate that blocks a crane pushes you toward site-built framing. Square footage and finish level matter everywhere, but here the lot itself often makes the call. Our written estimates account for all of it.
Sometimes, and it depends on gate width and staging space. Many Commerce homes built in the 1950s have side yards under five feet wide, which blocks a crane and most panel deliveries. We check utility trench depth and crane access before recommending any prefab route, and we’ll quote site-built as the fallback when the yard can’t take it. Call (903) 568-7222 for a straight answer on your specific lot.
Six to nine months is realistic from the day you sign to the day you get keys. Commerce’s plan-check counter adds two to three weeks on its own, and inspections get scheduled on the city’s calendar, not ours. Site-built units run longer than prefab, but prefab can stall if the yard can’t stage a crane.
Only things you choose to add or change. A buried obstruction we uncover during excavation, a foundation requirement Commerce flags at inspection, or a finish upgrade you pick mid-build all move the number. Every change gets a written addendum you sign before we proceed, so there’s no surprise billing at the end. That’s the fixed-price contract working. Call (903) 568-7222 to get your written estimate started.
Written by Troy Eastman, Owner at Benson ADU Builders, serving Commerce and surrounding communities since 2006.
