A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Home Addition Contractor Across Commerce
Adding square footage to a home in Commerce, CA typically costs between $180 and $420 per square foot depending on scope, finishes, and whether you’re going up or out. Most ground-floor additions we build here land in the $145,000 to $310,000 range, while second-story work runs higher due to structural reinforcement. Benson ADU Builders brings a written price before any work starts, plus the 365-Day Done Right Promise on every project. Call (903) 568-7222 to schedule a free on-site estimate and get real numbers for your specific lot.
We know Commerce the way only a contractor who’s pulled permits at the city’s Building & Safety counter can. The lots off Eastern Avenue, the mid-century bungalows near Bandini Boulevard, the rental-heavy blocks around Slauson Avenue – each neighborhood has its own setback rules and soil conditions. Our team handles the plan check process, the variance applications, and the inspections so you don’t have to decode the city’s requirements alone.
Why Benson ADU Builders Is Commerce’s Preferred Home Addition Contractor Company
Commerce homeowners don’t have time for contractors who vanish after the estimate. Our lead builder, Troy Eastman, runs every project with the same expectation: a written price, a confirmed schedule, and photo proof of progress at each phase. That’s not a slogan. It’s how we’ve built our reputation one addition at a time across Commerce’s 90040, 90022, and 90023 zip codes.
We answer the phone with a live person around the clock. When you call about a home addition in Commerce, you get a straight answer about feasibility, cost, and timeline – not a voicemail loop. Our technicians arrive in uniform, background-checked, and with the plan in hand. Every project gets a written guarantee stamped on it. If something isn’t right within 365 days, we come back and make it right. That’s the Relay Visibility Guarantee, and it’s how the Relay Home Co. family has operated since 2006.
The Home Addition Contractor team at Benson ADU Builders has seen what happens when Commerce lots get over-promised and under-scoped. A garage conversion that skips the variance check. A second story framed before Title 24 energy compliance is confirmed. We start with the site visit, the existing slab inspection, and the roof framing check – because that’s where real money gets lost or saved.
Second Story Addition Contractor in Commerce
A second story addition contractor in Commerce has to solve a problem most cities don’t present: adding vertical square footage on lots that were never designed for it. Many mid-century homes here sit on slabs that weren’t engineered for a second floor, and roof framing from the 1950s and 1960s often carries less load than modern code demands. That means the first step isn’t drawing pretty plans. It’s checking what’s under the stucco.
We scope every second-story project with a site visit to the existing crawlspace or slab, a look at the roof structure, and a conversation about what the city will require. A typical second-story addition in Commerce runs $220 to $420 per square foot, with $280k to $520k as a realistic full-project range once you factor structural upgrades, stairwell integration, and the fire separation requirements Commerce Building & Safety enforces on multi-story residential work.
Structural Reality Check Before Framing
Not every Commerce home can carry a second floor without significant reinforcement. We’ve opened walls off Gage Avenue and found undersized headers, termite-damaged bottom plates, and slab thicknesses that wouldn’t hold a new shear wall. That’s why our written price includes the structural assessment upfront – not as a surprise change order later.
Title 24 and Fire Separation in Vertical Additions
Commerce enforces California’s Title 24 energy code strictly on vertical additions, and a second story triggers fire separation requirements between floors that ground-floor work doesn’t face. Our plans account for these before the first inspection, which means fewer failed checks and fewer rework bills for you.
Garage Addition Contractors in Commerce
Garage addition contractors in Commerce deal with a specific local reality: dozens of attached garages here sit in nonconforming footprints that predate current setback rules. Converting one into living space – or building above it – often requires a variance from the Planning Division before Building & Safety will even look at your plans. We handle that paperwork as part of the project, and we’ve done it enough times to know which applications move quickly and which need a different approach.
A garage conversion or addition in Commerce typically runs $160 to $280 per square foot for a build-out within the existing footprint. If you’re adding a second story above the garage, expect $230 to $380 per square foot with the structural and fire-safety upgrades included. These ranges assume standard finishes; custom cabinetry, upgraded cladding like James Hardie fiber cement, or foundation rework will move the number.
Nonconforming Footprints and Variances
If your garage sits closer to the alley or side property line than current code allows, Commerce will treat it as a legal nonconforming structure. That’s workable, but it changes the approval path. Our team identifies this in the first site visit, not at the plan check counter, so your timeline and budget reflect reality from day one.
Working Within the Existing Slab Line
One of the most cost-effective garage additions we build in Commerce stays inside the original slab footprint. Our crew recently converted an attached single-car garage off Gage Avenue into a permitted junior ADU, framing a new 2×6 wall inside the existing slab line and setting a James Hardie-clad bump-out for the entry. Because the lot sat close to the alley, we pulled a minor variance before pouring the footing, then passed the city’s rough framing and energy inspections in two trips. The homeowner gained a rentable studio without losing street parking, thanks to a tandem pad poured at the driveway apron.
Trusted Brands We Service in Commerce
We build with brands Commerce homeowners can research and verify independently. Our projects use James Hardie siding and cladding for durability against Southern California sun and smog exposure, and we’re authorized to build with prefab systems from Abodu, Cover, and Dvele for homeowners who want a faster framing timeline and factory-controlled quality. Local stock for common James Hardie profiles and Abodu panel kits means fewer supply delays for Commerce projects. You get curated options instead of a take-it-or-leave-it product.
Common Home Addition Contractor Problems We See in Commerce Homes
- Nonconforming structure surprises. A garage or existing bump-out that predates current setbacks triggers a variance in Commerce, which adds weeks to plan check. We verify the footprint before you spend a dollar on drawings.
- Title 24 energy and fire separation rework. Attached additions face strict energy and fire-safety requirements in Commerce. When these aren’t designed in from the start, the rough inspection turns into an expensive redo.
- Slab and roof framing failures revealed at demo. Mid-century Commerce homes often hide rot, undersized joists, or thin slabs that only show up once demolition starts. Our site visits catch these before the change-order conversation happens.
- Scoped-from-a-phone-call pricing. Any contractor who prices a full addition without standing on the slab, checking the roof framing, and walking the lot lines is guessing. A written price should come from a written site report.
Pricing for Home Addition Contractor in Commerce, CA
Here are honest ranges for Commerce’s current market, based on what we’ve bid and built here:
- Room addition (ground floor): $145,000 – $310,000, typically $180 – $280 per square foot.
- Second story addition: $280,000 – $520,000, typically $220 – $420 per square foot.
- Garage conversion to ADU or living space: $90,000 – $210,000 for an existing footprint build-out.
- Garage addition (new space above or beside): $160,000 – $340,000.
- Sunroom addition: $70,000 – $160,000 depending on glazing and foundation work.
- Bump-out addition: $40,000 – $110,000 for 50 – 150 square feet.
What moves the price in Commerce: variance requirements, structural upgrades to 1950s – 1970s framing, Title 24 compliance features, and finish level. We put every number in writing before work starts, and our written price doesn’t shift unless you change the scope. Call (903) 568-7222 for a free estimate that accounts for your specific lot, your structure, and Commerce’s actual approval path.
We Also Serve Cities Near Commerce
Benson ADU Builders serves homeowners across Los Angeles, Long Beach, Anaheim, and Riverside. If your project sits outside Commerce proper, our Home Addition Contractor in Commerce team can coordinate with our crews serving neighboring communities. The same written pricing, the same 365-Day Done Right Promise, and the same live-person phone support apply wherever we build.
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 Home Addition Contractor in Commerce
Yes, in most cases, provided the existing garage can meet Commerce’s setback and fire separation requirements – and our team can confirm that during the first site visit. The conversion typically costs between $90,000 and $210,000 depending on whether we stay within the existing footprint or add square footage. If your garage sits in a nonconforming location, you’ll need a variance, and we handle that application as part of the project. Call (903) 568-7222 to get a written assessment for your specific garage.
Plan check at Commerce Building & Safety typically runs 4 to 8 weeks for a standard addition, but a variance application can add 3 to 6 weeks on top of that depending on the Planning Division’s current workload. We manage the submittal, the corrections, and the resubmittals on your behalf, and we’ll give you a realistic calendar – not a best-case one – before you sign anything. Call (903) 568-7222 to discuss your project’s specific approval path.
Structural reinforcement is the biggest cost difference. A second story in Commerce frequently requires upgrading the existing slab-to-frame connection, adding shear walls, and sometimes sistering or replacing undersized joists in the original roof framing. Fire separation between floors and the stairwell integration also add cost. Expect $220 – $420 per square foot for vertical work versus $180 – $280 for ground-floor additions. Call (903) 568-7222 for a number based on your actual structure.
You’ll typically need the garage conversion or addition covered under the same building permit set as the ADU, but Commerce may also require a separate electrical or mechanical permit depending on the scope. The critical step is confirming whether the existing garage footprint is conforming. If it’s not, the variance is its own approval track and it can’t ride on any other permit. We map this all out before submittal so there are no surprises at the counter. Call (903) 568-7222.
The honest answer: hidden structural conditions you can’t see until demo starts – rotted framing, undersized members, thin slabs, or abandoned plumbing in the wall cavity. That’s why our written price is based on a site visit and, when needed, a structural inspection before any work begins. If you change the scope, the price changes and you’ll see it in writing before the change happens. We don’t bill change orders without your signed approval. Call (903) 568-7222 to get a real number for your Commerce project.
Written by Troy Eastman, Owner at Benson ADU Builders, serving Commerce, CA with written pricing and the 365-Day Done Right Promise.
