Kitchen remodeling
Bathroom remodeling
Home additions & ADU
Roofing
Windows & doors
Driveway & pavers
FenceFree written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Fast, Reliable General Contractor Across Costa Mesa
Finding a general contractor in Costa Mesa who can handle a full remodel without making you juggle five different subs is harder than it should be. We’re Square One Builders, and we’ve spent years working the 92626 and 92627 tract blocks, the Westside bungalows, and the newer infill along Harbor and Newport Boulevard. One team manages your entire project, from structural and roofing down to cabinetry, tile, and fixtures. Call (877) 688-9930 to schedule a free estimate and get straight answers on what your remodel will actually cost.
Why Square One Builders Is Costa Mesa’s Preferred General Contractor Company
Our reputation in Costa Mesa comes from doing the unglamorous work well: opening walls, finding what’s actually in there, and pricing it honestly before the drywall closes back up. Homeowners on the Westside and in the College Park and Mesa Verde tracts keep calling us because we don’t hand over a rock-bottom fixed quote and then act surprised when a 1959 wall reveals knob-and-tube wiring. We plan for what Costa Mesa’s housing stock actually contains.
Brent Calloway leads every estimate and walks every job site. That matters when you’re spending $45,000 on a kitchen or $90,000 on an ADU. You get one accountable person who knows the difference between a load-bearing header on a 1950s slab-on-grade home and a partition wall that can come out with a Sawzall. Our Costa Mesa customers consistently tell us the same thing: the quote held because the allowances were written in up front.
Styles & brands we work with
Residential General Contractor in Costa Mesa
A residential general contractor in Costa Mesa handles the full scope of a home project: demolition, structural work, rough-in electrical and plumbing, drywall, flooring, cabinetry, tile, paint, and exterior systems like roofing and windows. You need us when the job touches more than one trade, because that’s where loose coordination falls apart. A kitchen remodel in Costa Mesa runs $14,000-$45,000, a bathroom remodel $9,000-$28,000, and a whole-home update lands between those depending on how far you go into the walls.
Full-Scope Remodels on Older Costa Mesa Stock
Most of our Costa Mesa work starts in 1950s and ’60s single-story tract homes. These houses have seen decades of patchwork fixes, and a gut remodel is the chance to correct deferred maintenance while the walls are open. We coordinate the electrical, plumbing, insulation, and drywall so the inspector signs off in one sequence, not six fragmented visits.
Room Additions and ADUs on Tight Lots
Costa Mesa lots are compact, and setbacks leave little room for error. A second-story addition or detached ADU on a 6,000-square-foot Westside parcel requires careful planning with the city’s planning department. We handle the drawings, the permit submittal, and the construction under one contract so you’re not the one chasing plan check corrections.
Hire a General Contractor in Costa Mesa
You hire a general contractor in Costa Mesa when the project is too big to coordinate piecemeal and too expensive to trust to guesswork. A home addition runs $45,000-$130,000, an ADU construction project $90,000-$220,000, and a garage conversion $30,000-$80,000. These are real numbers for this market, and they assume a licensed contractor handling permits, inspections, and all trade coordination, not a handyman working weekends.
One Contract, Every Trade
When you hire us, you sign one contract that covers roofing, windows, plumbing fixtures, cabinetry, counters, tile, and hardscaping if the project includes it. You don’t call five companies when the tile setter says the waterproofing isn’t his problem. We spec the right material for your project, and we stand behind the coordination because we’re the ones doing it.
Written Allowances Beat Shocking Change Orders
On older Costa Mesa homes, we write electrical, plumbing, and framing allowances into the contract before we start. When the tear-out reveals what it reveals, the correction is priced from an allowance that already existed in writing. You approve the exact number, in writing, before we touch it. No one likes a $12,000 surprise, and we’ve built our Costa Mesa reputation on making sure that doesn’t happen.
Trusted Brands We Service in Costa Mesa
We source and install from a portfolio of 50+ manufacturers, which means your Costa Mesa remodel gets intentional material selection, not whatever the local supply house had in stock. For roofing, we work with GAF, CertainTeed, and Owens Corning, so your re-roof during a whole-home remodel carries a real manufacturer warranty. On kitchens and baths, we coordinate Kohler, Moen, Cambria, and KraftMaid. And for Costa Mesa’s exterior work, James Hardie siding holds up to the marine layer far better than cheap composite. Because we stock parts locally and have established accounts with all of these brands, material lead times on Costa Mesa projects run shorter than if you were ordering on your own.
Common General Contractor Problems We See in Costa Mesa Homes
- Knob-and-tube wiring behind original walls. On 92627 Westside blocks and older 92626 tracts, opening a wall almost always turns up cloth-wrapped wiring from the ’50s. It’s a code issue the moment it’s exposed, and your permit requires correction before insulation goes back in.
- Galvanized and cast-iron plumbing at end of life. The supply lines in these postwar homes have been rusting from the inside for 60 years. Once a wall is open and the inspector sees it, replacement is mandatory, not optional.
- Termite and water damage at load-bearing corners. Costa Mesa’s coastal moisture works on exposed framing for decades. We’ve found header points so compromised that a second-story addition plan had to be re-engineered on the spot.
- Skipped inspections closing work in the wall. The most expensive problem we fix is when someone else drywalled over unpermitted wiring or unstrapped water lines. The city can’t sign off on work it can’t see, and tearing out fresh drywall to expose it doubles the cost.
See the difference
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AfterPricing for General Contractor in Costa Mesa, CA
Here’s what typical projects cost in Costa Mesa right now, based on the homes we actually work on:
| Project | Costa Mesa Price Range |
|---|---|
| Home Addition | $45,000 – $130,000 |
| ADU Construction | $90,000 – $220,000 |
| Kitchen Remodel | $14,000 – $45,000 |
| Bathroom Remodel | $9,000 – $28,000 |
| Garage Conversion | $30,000 – $80,000 |
These numbers assume a permitted project with a licensed general contractor running the job. What moves the price within each range is the condition of what’s behind the walls and the finish level you choose. A kitchen with Cambria quartz and custom KraftMaid cabinets lands at the higher end. A bathroom with a standard Moen fixtures package and mid-grade tile runs lower. Call (877) 688-9930 for a free estimate and a line-item quote before you commit to anything.
We Also Serve Cities Near Costa Mesa
Our crew runs projects throughout Costa Mesa and the surrounding communities, including Newport Beach, Fountain Valley, Huntington Beach, and San Joaquin Hills. If your project sits just over a city line, call us anyway. Our General Contractor team manages permitting across Orange County, and we know the different plan check requirements from city to city.
Serving Costa Mesa, CA — Our Local Coverage Area
We’re based in the Costa Mesa 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 General Contractor in Costa Mesa
Allowances exist because a 1950s or ’60s Costa Mesa home is a known unknown until the walls come down. We write dollar allowances for electrical, plumbing, and framing corrections based on what we typically find in 92626 and 92627 homes: knob-and-tube wiring, aging galvanized pipe, and termite damage at load points. A fixed number with no allowances is a guess, and any contractor who’s opened older Costa Mesa walls knows it. Call (877) 688-9930 and we’ll walk you through exactly what your allowance should be.
Pulling a permit in Costa Mesa triggers sequential inspections that happen while the work is visible. Once a wall is open, the inspector will require exposed knob-and-tube wiring be brought to current code, galvanized supply lines replaced, and any damaged framing sistered or rebuilt. You can’t legally close the wall until the electrical, plumbing, and framing rough-ins are signed off. We schedule to those inspection points so the project keeps moving.
We stop, photograph, write the correction as a change order with a priced allowance, and get your written approval before doing the work. On a 92627 Westside block, our crew opened the kitchen wall of a 1959 single-story tract home and found live knob-and-tube wiring and a rusted galvanized supply line feeding the old sink rough-in, plus termite-chewed framing at the load-bearing corner where the header was going in. We wrote the electrical and plumbing corrections and the framing repair as a change order, got it approved in writing, and only then pulled the rough-in forward for inspection sign-off. That’s the standard on every Costa Mesa tear-out.
Yes, and we do it regularly. Costa Mesa’s compact parcels and setback rules mean the design has to work hard: a detached ADU along the rear property line, a garage conversion with a new footing, or a second story over an occupied single-story home. We manage the planning submittal, structural calcs, and sequencing so your household keeps functioning while construction happens in phases. ADU construction in Costa Mesa runs $90,000-$220,000 depending on size and finish.
We coordinate the full material scope: GAF, CertainTeed, or Owens Corning for roofing; Kohler, Moen, or Grohe for plumbing fixtures; Cambria or Silestone for countertops; KraftMaid or Wellborn for cabinetry; and James Hardie for siding. You pick the tier that fits your budget, and we spec the right material for your project without switching contractors mid-stream.
Get a Free General Contractor Estimate in Costa Mesa
If you’re planning a remodel, addition, or ADU in Costa Mesa, get a real number before you go further. Brent Calloway will walk your project, look at what’s behind the walls, and give you a line-item quote with honest allowances, not a sales pitch. Call (877) 688-9930 or reach out through our website to schedule your free estimate. Your remodel, fully managed, from the ground up.
Written by Brent Calloway, Owner at Square One Builders, serving Costa Mesa and Orange County.