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
Hiring a general contractor in Costa Mesa usually means one of two things: you’re remodeling a 1940s – 1950s west-side bungalow on a tight lot, or you’re upgrading a mid-century Mesa Verde ranch and want the whole job handled without juggling subs. Either way, you need one point of accountability. That’s what Key Step Construction provides. We work across Costa Mesa every week, from the Eastside to the 92626 corridor near South Coast Plaza, and we quote real numbers before any wall comes down. Call (855) 382-0824 to schedule a free estimate and get a written scope of work.
Why Key Step Construction Is Costa Mesa’s Preferred General Contractor Company
Costa Mesa homeowners keep calling us for the same reason: we plan for what’s inside the walls before we bid the finish work. A 1952 stucco bungalow off 19th Street is not the same job as a 1968 Mesa Verde plan home, and we don’t price them as if they were. Noel Garrity leads every project with the same routine: inspect first, write allowances for the unknowns, and get any change order priced and signed before we touch it. That approach has built our local reputation block by block, from the Westside up through the 92627 zip code and over to the 92626 side.
Our Costa Mesa clients tell us the difference comes down to how we handle surprises. We’re a General Contractor team that writes the permit-triggered upgrades, framing repairs, and waterproofing failures into the contract as line items, not as vague “contingency” language. That’s why homeowners who have lived through a fragmented, multi-subcontractor remodel say working with us feels entirely different. One contract. Every system. From the roof down to the foundation.
We serve all three Costa Mesa ZIP codes: 92626, 92627, and 92628. Response time for an initial site visit is typically within a few business days, and we schedule estimates around your availability. If you’re in the planning stages and want to know whether your west-side lot can support a rear addition under current setback rules, call us and we’ll walk the property with you.
Styles & brands we work with
- Kitchen remodeling
- Bathroom remodeling
- Home additions & ADU
- Roofing
- Windows & doors
- Driveway & pavers
- Fence
Hire a General Contractor in Costa Mesa
Hire a General Contractor in Costa Mesa when the job crosses more than one trade or requires a permit. On this side of Costa Mesa, that almost always means a rear addition on a 25-foot frontage lot, a garage conversion into living space, or a whole-home rewire triggered by an open wall. We manage the full scope: demo, framing, rough-in, waterproofing, drywall, finish, and final inspection. The city’s plan check and inspection process is straightforward once you know the codes, and we’ve been through it enough times to anticipate what plan check will flag before you pay for drawings.
Rear Additions on Narrow West-Side Lots
The original 1940s – 1950s tract homes in 92627 sit on narrow lots with original frontages around 25 feet. That means additions almost always run to the rear, and setbacks plus utility coordination become the real constraints. We design around both from the first site visit, so plan check doesn’t send you back to the drawing table.
Full-Scope Remodeling With One Contract
Interior and exterior work in Costa Mesa often needs to happen together: a kitchen remodel opens a wall, which exposes wiring, which triggers a panel upgrade, which means the stucco has to be patched, which leads to repainting the exterior. We carry all of it under one contract so you never coordinate between an electrician, a stucco crew, and a painter.
General Contractor Services in Costa Mesa
General Contractor Services in Costa Mesa cover the full range of home remodeling and renovation scopes. On a typical job here, we move from demolition through rough framing, electrical, plumbing, insulation, drywall, tile, cabinetry, countertops, and final trim. For exterior work, we handle roofing, siding, windows, doors, fencing, and hardscaping under the same accountability structure. Costa Mesa’s older wood-frame stucco houses respond well to this approach because the envelope and the interior are usually failing in the same places: fascia rot from the marine layer, termite damage at sill plates, and outdated wiring behind lath-and-plaster walls.
Kitchen and Bath Remodels
A Costa Mesa kitchen remodel typically runs $14,000 – $45,000, and a bathroom remodel $9,000 – $28,000. The spread comes down to what’s behind the walls and whether you want premium lines like Cambria countertops and KraftMaid cabinetry or a solid mid-range selection. We write both into the allowance schedule so you know exactly what you’re approving.

Garage Conversions and ADUs
On the west side especially, the original one-car garage is often the most underused square footage on the lot. Garage conversions in Costa Mesa run $30,000 – $80,000 depending on foundation condition and utility runs. For a full detached ADU, expect $90,000 – $220,000, and we support prefab options through partners like Abodu, Dvele, and Mighty Buildings when the lot dictates a faster path.

Trusted Brands We Service in Costa Mesa
Costa Mesa homeowners ask us about fencing and hardscaping brands all the time, and we work with Master Halco, Ameristar, Jerith, and Bufftech because their product warranties hold up in our coastal air. For roofing, we’re aligned with GAF, CertainTeed, and Owens Corning. On windows and doors, PGT and Therma-Tru handle the WUI code requirements that come up on the 92626 side during Santa Ana season. James Hardie siding is our go-to for stucco replacement where the marine layer has done its damage. We hold local stock for common repair parts, so turnaround on change orders stays short for Costa Mesa customers. Your material choices, our expertise.
See the difference
Before
After
Before
After
Before
AfterCommon General Contractor Problems We See in Costa Mesa Homes
- Cloth-wrapped wiring behind lath-and-plaster walls. West-side bungalows from the 1940s and 1950s often still carry original cloth-insulated wiring. Open any wall and code will require a rewire. We write electrical allowances into the contract before demo starts.
- Termite-chewed sill plates and dry rot at the envelope. The persistent morning marine layer and salt air work on fascia, window trim, and sill plates year-round. On older stucco homes, we inspect these areas in the first site visit and price repairs separately.
- Narrow 25-foot frontage setbacks on 92627 lots. A rear addition that looks simple on paper can fail plan check if the side-yard setback isn’t accounted for. We measure and design against the actual lot lines, not assumptions.
- Failed waterproofing in original wet areas. Shower pans and tub surrounds from the 1950s were not built to modern waterproofing standards. We use Schluter systems on every wet-area remodel and coordinate with the tile scope so the substrate is correct before any tile goes up.
Pricing for General Contractor in Costa Mesa, CA
Costa Mesa pricing reflects the housing stock: older homes, tight lots, and code upgrades that surface once walls are open. Here is what we quote for common scopes in the 92626, 92627, and 92628 ZIP codes:
| Project Scope | Typical Costa Mesa Range |
|---|---|
| Kitchen Remodel | $14,000 – $45,000 |
| Bathroom Remodel | $9,000 – $28,000 |
| Home Addition | $45,000 – $130,000 |
| ADU Construction | $90,000 – $220,000 |
| Garage Conversion | $30,000 – $80,000 |
What moves the number most on a Costa Mesa job is not the finish level; it’s what the house gives up when we open it. Wiring, framing, termite damage, waterproofing failures. We write allowances for those conditions into every contract, so the line items are priced and approved before we touch the wall. Call (855) 382-0824 for a free estimate and a written scope. Plan it once, build it right.
We Also Serve Cities Near Costa Mesa
Key Step Construction is based in Buena Park and serves Costa Mesa plus the surrounding communities of Newport Beach, Fountain Valley, Huntington Beach, and San Joaquin Hills. If you’re right on the city line or just over it, we still take the call. Same local knowledge, same written allowances, same single-contract accountability.
Serving Costa Mesa, CA - Our Local Coverage Area
We serve Costa Mesa and nearby communities. Use the map below to see the area we cover. If you’re nearby, we can almost certainly help.
FAQs About General Contractor in Costa Mesa
Outdated wiring, termite-chewed framing, and failed waterproofing are the three most common budget movers in Costa Mesa’s 1940s – 1970s housing stock. We handle these by writing allowance schedules into the contract before demo, so when a wall opens and we find cloth-wrapped wire, the rewire is already priced as a line item, not a surprise. Call (855) 382-0824 for a free estimate that includes a written allowance structure.
We plan for them from the first site visit. Any time you open a wall in a 1950s Costa Mesa house, the city will require the exposed wiring to come up to current code, and often the panel too. We identify these triggers early, write them into the scope, and get the inspector’s sign-off before finish work begins. Call (855) 382-0824 to have us walk your home and flag likely trigger points.
Yes, but it requires measuring against the actual lot lines. The original 92627 bungalows sit on 25-foot frontages, so additions typically run to the rear and must clear side-yard setbacks precisely. We measure on the first visit and design to the property’s real dimensions, avoiding plan check rejections. Call (855) 382-0824 to schedule a lot walk.
We do, and it’s one of the most popular projects in 92627. The original one-car garages on those post-war lots are often the right footprint for a junior ADU or full conversion, running $30,000 – $80,000 for a garage conversion and $90,000 – $220,000 for a detached ADU depending on the foundation and utility runs. Call (855) 382-0824 for a free site assessment.
It protects you against unapproved change orders and mid-draw budget blowups. Every unknown condition we can anticipate from the housing stock gets a line item, and any condition we can’t see gets an allowance you approve in writing before we proceed. That’s how we keep the draw schedule intact and the final number honest. Call (855) 382-0824 for a free estimate with the full written scope.
On a 1950s bungalow near the Westside’s 19th Street, our crew opened a kitchen wall and found cloth-wrapped wiring and termite-chewed sill plates behind the stucco. Before any new cabinet or Cambria countertop went in, we added a change order for a full rough-in rewire and sistered framing, got the city inspector’s sign-off, and kept the original draw schedule intact. The homeowner ended up with a safe, permitted layout and no surprise line items after the walls closed.
If you’re planning a remodel, addition, ADU, or full-scope renovation in Costa Mesa, call Key Step Construction at (855) 382-0824. We’ll schedule a free estimate, walk the property, and give you a written scope with real numbers. One contractor. Every system. From the roof down to the foundation.
Written by Noel Garrity, Owner at Key Step Construction, serving Costa Mesa since day one of this company.