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 Lomita
A home addition or ADU in Lomita typically runs $45,000 to $130,000 for a full project, and detached ADUs often land between $90,000 and $220,000 depending on foundation work and utility runs. You already know the real cost of waiting, though: the house that no longer fits, the in-law you want nearby, the rental income that could offset a mortgage. We get calls from Lomita homeowners every week who have been thinking about this for two years. The difference is we answer our own phone when you finally dial it: (877) 610-1318.
Lomita is its own animal. The housing stock, the permitting office, even the way marine air hangs over Narbonne Avenue until noon all shape how an addition actually gets built here. We know that because our crews have been on Lomita streets long enough to recognize the foundation quirks on a 1952 bungalow before we even pull a tape measure. Serving Lomita means more than driving a truck down Western Avenue. It means knowing what city hall will ask for, what the soil will do, and how to stage materials on a 4,000-square-foot lot without blocking your neighbor’s driveway.
Why Barrett & Sons Construction Is Lomita’s Preferred Home Additions & ADU Company
We started in 1998, and Tom Barrett still runs this company with his name on every contract. That matters in a city like Lomita, where half the homeowners have already been burned once by a company that quoted one number over the phone and produced another after the slab was poured. We publish our license number. We answer the phone with a person, not a call tree. And every scope change arrives as a written change order before work moves, not as a surprise invoice at the end.
Lomita homeowners tell us the same thing over and over: they just want a contractor who will show up, do what he said, and stand behind it. Our 90-Day Done Right Promise is printed on every contract we write. If something isn’t right, one call brings Tom back to make it right. That promise means something specific in a city where the existing housing stock was largely built between 1945 and 1965, because the moment you open a wall or disturb a foundation, you find what the original builders left behind. We plan for that. Most crews don’t until it’s too late.
Our Home Additions & ADU Services in Lomita
ADU Design & Permitting
Lomita runs its own building department, separate from LA County and separate from Torrance. That’s not a technicality. It changes how long plan check takes, what the planners ask for, and how quickly an inspector can get to your property on Paseo de las Tortugas or 255th Street. We handle the design and the permit package for Lomita’s process directly, because we’ve sat in that city hall office enough times to know whose signature matters. You don’t need a permit expediter. You need a contractor who already knows the people behind the counter.
Garage Conversion ADU
Lomita’s postwar homes often came with detached garages that no longer fit anything bigger than a single car, which makes them strong conversion candidates. But many of those garages sit on undersized footings, with uninsulated walls and electrical panels that were never rated for living space. Converting one properly in Lomita means addressing the foundation, the power, and the ventilation - and often Windows & Doors - Lomita upgrades - not just slapping drywall over studs and calling it a day. Most conversions we price in Lomita run $30,000 to $80,000, and we pull the permit on every one.
New Detached ADU
A new detached ADU in Lomita gives you a clean slate, and in most cases that’s the smart play if your lot off Narbonne Avenue has the space. We handle the site prep, the utility trenching, the foundation, and the full build. Lomita’s expansive clay soils are the thing to plan around here. Footings and slab work need to account for that movement, or the ADU will move with it. New detached units in Lomita generally range from $90,000 to $220,000, and the biggest variables are soil engineering and how far we’re running gas and water lines.
Junior ADU & Interior Conversion
Plenty of Lomita homes already have a den, a bonus room, or a third bedroom that nobody uses. A junior ADU, which is typically under 500 square feet and within the existing home’s walls, often makes more sense than a full addition. It costs less, permits faster through Lomita’s building department, and adds rentable square footage without touching the rear yard. We help you figure out whether a JADU actually qualifies on your lot, because Lomita’s zoning has its own quirks about entry access and kitchen setup.
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.
Trusted Brands We Service in Lomita
When we build an ADU or addition in Lomita, the materials have names you can look up before you spend a dollar. We install Techo-Bloc and Cambridge Pavers on hardscape and patio work, and Quikrete products when concrete conditions in Lomita’s marine-layer climate call for a slower, more controlled cure. We don’t haul mystery materials off a van and hope you won’t ask. You can walk into any supplier in the South Bay and verify what we’re using. That’s the point.
Common Home Additions & ADU Problems We See in Lomita Homes
- Original 1940s-1960s foundations under new load. Most Lomita additions attach to a home built before modern seismic codes existed. We regularly find pier-and-beam foundations that were never bolted to the concrete, which means the addition can move independently of the original structure during the small tremors the South Bay gets from the Newport-Inglewood fault. It’s fixable. It’s not optional.
- Tight lots with no staging room. Lomita’s lots run small, and many homes sit close enough to the property line that a Dumpster and a lumber stack cannot both fit anywhere. We stage materials off site and bring them in as needed, which takes coordination and discipline. If a contractor tells you it’s no problem on a 40-foot lot, get a second opinion.
- Asbestos tiles and original single-wall wiring hiding behind old stucco. Lomita’s housing stock carries what the 1950s left behind. When we open up a wall or pull up flooring on an addition tied into the original envelope, we frequently find materials that need proper testing and abatement before any framing work continues. A reputable Lomita GC plans for that in the estimate instead of discovering it in week three.
- Marine-layer moisture slowing exterior work. Lomita sits about four miles from the coast, and the marine layer can sit over the city until late morning for much of the year. Concrete cures slower in that damp air, and stucco application windows get tighter. We schedule exterior pours and finishes around Lancaster’s dry heat patterns, not against them. It’s a small thing that shows up in how the work actually holds up.
Pricing for Home Additions & ADU in Lomita, CA
We already mentioned the headline numbers for Lomita: full home additions run $45,000 to $130,000, and ADU construction generally lands between $90,000 and $220,000. Room additions without kitchens or baths sit at the lower end of that range. Garage conversions in Lomita typically run $30,000 to $80,000, which is often the most cost-effective path to an income unit on a typical Lomita lot. What moves the final number here is mostly the foundation and soils work, the distance to existing utility lines, whether your home needs seismic retrofitting before we can tie into it, and if you’re bundling our Roofing in Lomita into the scope. We give you a written, line-item estimate before any work starts. If the scope changes, the price change is on paper first. Call (877) 610-1318 and we will walk the property with you and put real numbers on the table, for free.
Key Takeaways for Lomita Homeowners
- Home additions in Lomita typically cost $45,000-$130,000; detached ADUs range $90,000-$220,000.
- Lomita has its own building department, and permit timelines there differ from LA County and Torrance.
- Many Lomita homes need foundation or seismic work before an addition can tie in safely.
- We pull permits, issue written change orders, and back every job with a 90-Day Done Right Promise.
- Call (877) 610-1318 to schedule a free estimate, and a live person answers.
We Also Serve Cities Near Lomita
Our crews cover Lomita and the immediate South Bay neighbors: Torrance, Rolling Hills Estates, San Pedro, and West Carson. If you’re just over the line near Lomita Boulevard in Home Additions & ADU in Lomita country or up toward Palos Verdes Drive North, the same crew that knows Lomita’s permitting office can handle your project too.
Serving Lomita, CA - Our Local Coverage Area
We’re based in the Lomita 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 Lomita
A home addition in Lomita typically costs $45,000 to $130,000. Room additions without plumbing sit at the lower end, while second story additions and anything that adds a bathroom push toward the top. The biggest Lomita-specific variables are foundation condition and how the city’s independent building department processes your permit. Call (877) 610-1318 for an exact quote, written and free.
Yes. Every eligible ADU, garage conversion, and home addition in Lomita gets a permit pulled and an inspection signed. Lomita runs its own building department, and we handle that process directly rather than handing it to an expediter. The inspector works for you, not for us, which is exactly why we like the process Lomita runs.
Most full additions in Lomita run 4 to 8 months once the permit is issued, and garage conversions often finish in 3 to 5 months. Lomita’s building department operates on its own calendar, and plan check times there can run slower than neighboring Torrance, so we build that buffer into the schedule from day one rather than promising a date we cannot hold. You’ll get a written schedule when we start, and written change orders if anything shifts.
Yes. We walk the property with you, in Lomita, at no cost and with no trip charge inside the county. You get a written, line-item estimate that names the materials and the scope clearly. If you have a written estimate from another contractor, we’ll give you a free second opinion before you sign anything.
Every job is backed by our written 90-Day Done Right Promise. If something isn’t done right, one call brings Tom Barrett back. That’s not a phrase on a flyer. It’s printed on your contract. Call (877) 610-1318 and ask us anything, including what we’ll put in writing before you commit.
Schedule Your Free Lomita Home Addition or ADU Estimate
If you live near Lomita Park, off Oak Street, or anywhere in the 90717 ZIP, we’re close. You can call us at (877) 610-1318 and a person answers, 24 hours a day. We’ll walk your lot, talk through what Lomita’s city hall will require, and put a real number in your hand before any work begins. If you’re also considering interior work down the line, we handle Kitchen Remodeling in Lomita and Bathroom Remodeling in Lomita with the same permits-included, written-change-order approach. But for the addition or ADU you’ve been thinking about: call now, get the free estimate, and deal with someone whose name is on the truck.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Lomita and the South Bay.