Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
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AfterFast, Reliable Home Additions & ADU Across Commerce
If you own a home in the small residential pocket of Commerce, you already know what most people don’t: this city is built for industry, not for houses. That means finding a contractor who actually understands residential construction here matters more than it does in Bell Gardens or Montebello. We’re Barrett & Sons Construction, a Home Additions & ADU company that has been owner-operated since 1998, and we answer our own phone at (877) 610-1318. Our crew serves Commerce directly, and if you’re in the 90101 ZIP, we can be on-site to look at your property without a trip charge inside the county.
Why Homeowners in Commerce Call Barrett & Sons for Additions and ADUs
Plenty of construction outfits work in Commerce, but almost all of them spend their days on warehouses, loading docks, and tilt-up concrete. Residential work is a side thought. For us, your ADU or room addition is the whole job. Tom Barrett puts his name on the contract, his sons run the crews, and every change order arrives in writing before a single nail moves. That’s how we’ve done it for over 29 years, and it’s why Commerce homeowners who are picky about who they let onto their property tend to stick with us.
You can verify us before you sign. Tom’s name, address, and license number are published and easy to look up. Our crew members are background-checked and uniformed on every visit. And every job, from a garage conversion to a second story addition, carries our written 90-Day Done Right Promise. If it’s not right, one call brings Tom back. That’s not a slogan; it’s on paper.
We also answer the phone 24/7. When you call about an ADU in Commerce, you get a live person, not a voicemail box or an out-of-state call center.
Our Home Additions & ADU Services in Commerce
Commerce has specific realities that shape what makes sense for your property. The housing stock is mid-century, modest, and aging. Lot sizes are small. Setbacks are tight. And because so much of the surrounding land is zoned for industrial use, privacy, noise, and dust are real considerations in how we design and build. Here are the four services we do most for homeowners in this city:
ADU Design & Permitting
An ADU in Commerce starts with the city’s permitting process, and this is where a lot of projects stall. We handle the drawings, the submittals, and the resubmittals. Tom has spent years working with local building departments across Los Angeles County, and he knows which details reviewers flag in Commerce specifically. Permits get pulled on every eligible job, and inspections get signed. The permit inspector works for you, not for us. That’s why we like him.
Garage Conversion ADU
For many Commerce homeowners, the detached garage is the fastest path to a rentable unit or guest suite. A typical garage conversion here runs $30,000 to $80,000 depending on whether we’re adding a bathroom, upgrading the electrical service, or redoing the foundation. Older garages in the residential pocket of Commerce often have undersized footings and single-wall construction that needs structural correction before drywall goes up. We scope that in writing before work begins.
New Detached ADU
If your lot can fit one, a new detached ADU in Commerce generally falls between $90,000 and $220,000. That range reflects everything from a simple studio to a two-bedroom unit with its own laundry and mini-split HVAC. Commerce gets hot in summer, away from the coastal marine layer, so we design for real afternoon heat. Insulation, window placement, and roof ventilation aren’t optional add-ons here.
Junior ADU & Interior Conversion
A JADU is often the most affordable way to create legal living space inside an existing home in Commerce, typically by converting a garage, a large bonus room, or part of the first floor into a small self-contained studio. This can be half the cost of a new detached unit and doesn’t require the same yard space. We’ll walk you through the owner-occupancy requirements that apply to JADUs and get everything in writing before you commit.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
What to Look For When Comparing Home Addition Contractors in Commerce
Most people start by asking about price. That’s reasonable, but in Commerce the bigger question is scope discipline. Industrial contractors are accustomed to change orders on warehouse build-outs where a 10% overrun is absorbed by a corporate budget. Your home addition isn’t a line item for a logistics company. It’s your money.
Here’s the comparison that matters: ask any contractor whether every allowance and every scope change arrives as a written change order before work proceeds. If they hesitate, that’s your answer. An allowance that isn’t on paper is a surprise waiting for a date. We put every scope, every allowance, and every price change in writing before a single nail moves. No surprise invoices at the end.
The second thing to verify is permits. In Commerce, where much of the local construction culture has been built around commercial work, some residential jobs slide through without proper permits. That’s a liability you’ll carry for as long as you own the house. We pull permits and sign inspections on every eligible job. That’s not negotiable, because the last contractor most of our customers used told them permits were optional.
Third, ask who actually shows up. We’re the Home Additions & ADU team where the owner’s sons run the crews. Tom Barrett is on-site most days. This is not a franchise dispatching strangers from a call center.
How Commerce’s Climate Changes How We Build
Sitting in the eastern LA Basin away from the coast, Commerce runs noticeably hotter in summer than cities closer to the ocean. Afternoon temps in July and August routinely push into the 90s, and the surrounding asphalt, concrete, and truck traffic hold that heat into the evening. For an ADU or addition in the 90101 ZIP, that means two things: first, insulation and air sealing matter more than they would in Santa Monica. Second, concrete cures differently here. We schedule pours and control joints around the heat so your slab doesn’t crack before the framing even starts.
There’s another factor specific to Commerce. Heavy diesel truck traffic on the I-5 and the surrounding arterials affects air quality, and on high-pollution days, LA County AQMD work-hour restrictions can apply to certain construction activities. A local crew that knows how to sequence work around those restrictions keeps your schedule predictable. That’s a knowledge base most out-of-town contractors simply don’t have.
We serve the whole residential area of Commerce, including the streets closest to the industrial perimeter where noise and dust from neighboring facilities are constant. We design for that reality, whether that means better filtration in the HVAC, double-pane windows, or just a more careful sequencing of when we open up a wall.
Trusted Brands We Install in Commerce
We don’t put mystery materials off the back of a van into your home. On ADU kitchens and baths, we regularly install Schluter waterproofing systems under tile, and we’ve used Grohe fixtures and GAF roofing products on our Commerce jobs. These are brands you can look up. If a specific material or manufacturer matters to you, tell us during the estimate, and we’ll line-item it in writing.
Common Home Addition & ADU Problems We See in Commerce Homes
- Undersized electrical panels. Most mid-century homes in Commerce were built with 100-amp panels, and many with less. Adding an ADU almost always requires a service upgrade, and we scope that from the start so it’s not a surprise line item halfway through.
- Foundation issues from shifting clay soil. The ground in this part of the LA Basin expands and contracts with moisture. Older detached garages often have cracked slabs or footings that need repair before a garage conversion can pass inspection.
- Unpermitted prior work. We regularly find unpermitted additions, enclosed patios, and converted garages in Commerce homes. Before we add square footage, we have to understand what’s already there and make sure the final occupancy permit will issue cleanly.
- Heat-related roof and attic failures. The summer heat in Commerce bakes attics, which shortens the life of roofing materials and makes upstairs additions uncomfortable if ventilation wasn’t designed properly. We address this during planning, not after you’ve lived through a July or two.
Pricing for Home Additions & ADU in Commerce, CA
A full home addition in Commerce typically runs $45,000 to $130,000. An ADU runs $90,000 to $220,000 for new detached construction, while a garage conversion falls in the $30,000 to $80,000 range. A room addition or sunroom without plumbing or significant foundation work can come in at the low end of the home addition range. What moves your price within those bands is the size of the space, whether you’re adding a bathroom or kitchenette, the condition of your existing foundation and electrical panel, and the finishes you choose.
We give free written estimates. We also honor a permanent 10% Senior & Veteran discount, a $40 discount on any repair over $200, and a free second opinion on any written estimate you already have from another contractor. Call (877) 610-1318 to schedule yours.
How Much Does a Garage Conversion ADU Cost in Commerce?
In Commerce, a garage conversion ADU typically costs between $30,000 and $80,000. At the low end, you’re looking at a studio with basic finishes, minimal plumbing, and a panel upgrade already in place. Toward the top, you’re adding a full bathroom, a kitchenette with mid-tier finishes, seismic retrofit work on the garage walls, and maybe a new roof. If the garage slab is cracked or the footings are undersized, that adds cost before the interior work even starts. The best way to know your number is to get a written, line-item estimate. Call (877) 610-1318, and we’ll walk the property with you.
Will the Price Change Once Work Starts?
Not without your signature on a written change order. That’s the whole point of how Tom Barrett runs this company. Every scope, every allowance, every price change arrives as a written change order before work proceeds. If you want to upgrade a finish, adjust a wall, or add a window, you’ll see the cost in writing and approve it before anything happens. No surprise invoices at the end. If a contractor can’t promise you that, the phone quote is worthless.
We Also Serve Cities Near Commerce
Besides Commerce, our crews handle Kitchen Remodeling in Commerce and Bathroom Remodeling in Commerce for homeowners throughout the area. We also serve Maywood, Bell, Cudahy, and Bell Gardens, so if you’re just across the city line, we can still get to you without a trip charge inside the county.
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 - Home Additions & ADU in Commerce
Planning and permitting typically take two to four months before construction starts, depending on the city’s review queue. We can get a full estimate on your property within days of your call to (877) 610-1318, and we’ll keep you posted on every permitting milestone in writing.
Yes. Commerce’s residential housing is concentrated in a relatively small area within the 90101 ZIP, and our crews serve all of it, including homes on streets adjacent to the industrial corridors. We know the neighborhoods, the lot patterns, and the typical condition of the housing stock here.
Commerce follows California state ADU law, but the local building department has its own submittal process and plan review standards. We handle those details from the first drawing through the final inspection. The permit inspector works for you, not for us, and we make sure the project passes cleanly the first time where possible.
Generally, ADU costs in Commerce are in line with the rest of the eastern LA Basin, which means $90,000 to $220,000 for detached units. What can shift costs here is the need for seismic retrofits on older structures and electrical panel upgrades, both of which are common in this housing stock. We’ll scope those costs in your written estimate, not spring them later.
Every job we do, including home additions and ADUs in Commerce, carries our written 90-Day Done Right Promise. If something isn’t done right within that window, one call brings Tom back to make it right. We also pass through manufacturer warranties on the named-brand materials we install, like Schluter, Grohe, and GAF. Call (877) 610-1318 for details.
Written by Tom Barrett, Owner at Barrett & Sons Construction. Proudly serving Commerce, CA since our founding, with permits pulled, inspections signed, and every price change in writing before work begins.