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 Costa Mesa
A home addition in Costa Mesa typically costs $180 – $340 per square foot for a room addition, $220 – $400 per square foot for a second story, and $150 – $250 per square foot for a garage conversion depending on finish level, foundation work, and whether your 1950s – 1970s ranch home needs panel or plumbing upgrades before framing starts. Most additions here take 4 – 7 months from permit to final inspection, and the single biggest variable is lead time on custom materials, not labor. If you’re planning a high-end addition with architectural glass and custom millwork, call (350) 203-6060 for a written price before you order a single window or door.
Why Lodgewick ADU Orange County Is Costa Mesa’s Preferred Home Addition Contractor Company
We have built additions and ADUs across College Park, Mesa Verde, and the Eastside since 2010, and the second thing we hear from Costa Mesa homeowners is how many contractors ghosted them after the first walkthrough. The first thing we hear is frustration about prices that moved after the contract was signed. That’s exactly why every Lodgewick project starts with a written price and ends with a written guarantee, the 365-Day Done Right Promise that says if the work is not right, we come back and make it right, within a full year, at no cost to you.
We know Costa Mesa’s building department like the inside of our own truck. When a planner in College Park asks for fire-truck turning radii on a rear-alley garage conversion, we have already drawn the hammerhead turnaround and submitted the Kerdi-board moisture detail with the permit set. Russ Delmar, who leads our team, has walked enough Mesa Verde lots to know before the first site visit whether your galvanized plumbing and 100-amp panel will hold up the permit or kill the budget. We answer every call, 24/7, with a live person, not a voicemail loop.
Bathroom Addition Contractor in Costa Mesa
A Bathroom Addition Contractor in Costa Mesa handles everything from a 60 sq ft guest bath bumped out from the hallway to a 140 sq ft primary bath addition with a freestanding tub, curbless shower, and heated floor. On Costa Mesa’s slab-on-grade ranch homes, a bathroom addition means saw-cutting concrete, running new drain lines, and often relocating a stack vent through an existing stucco wall, which is why our written price includes the plumbing, the patchback, and the tile waterproofing before the first cut.
Bathroom additions in Costa Mesa typically run $35,000 – $85,000 depending on the fixture package, waterproofing system, and whether you’re tying into existing ABS drain lines or replacing original cast iron. The long-lead item is usually the tile if you’re sourcing handmade or large-format pieces, so we order at contract signing and hold the price even if the lead time stretches.
What to expect during your bathroom addition
We lay out the new footprint, confirm the drain slope through the existing slab, and set a defined arrival window for every crew day. You’ll know who is on your property because every technician is background-checked and uniformed. The jobsite is cleaned daily, not at the end.
How we protect against moisture
Costa Mesa’s morning marine layer means an open slab can sit damp for weeks if the weather turns. We stage waterproofing materials first and cover the slab each evening, so your Kerdi-board or Wedi details go in against dry concrete, not a sweating cut.
Bedroom Addition Contractor in Costa Mesa
A Bedroom Addition Contractor in Costa Mesa handles single-room expansions and full primary-suite additions that give a 1950s ranch home a real master bedroom with a walk-in closet and dedicated bath. On 6,000 – 7,200 sq ft lots, the addition often pushes into the side yard, which is why Costa Mesa’s 10-ft side setbacks and case-by-case planner review change the size of what you can build, even when the lot looks wide enough.
Bedroom additions in Costa Mesa generally run $60,000 – $130,000 for a 200 – 400 sq ft room with closet, windows, insulation, drywall, and finish trim. If the room is part of a second-story addition, the price moves to the $220 – $400 per square foot range because you’re adding structural engineering for wind-load uplift clips, a new stairwell, and fire-rated separation at the existing wall.
Planning around the setback
We measure to the property line, confirm your side yard against the city’s setback table, and adjust the floor plan before the permit set is drawn. No surprises after the foundation is in.
Foundation and egress requirements
A bedroom addition needs an egress window sized to code, not just a standard double-hung. We spec the egress, the header, and the slab tie-in in the written estimate, so the budget includes the structural work, not just the framing.
Trusted Brands We Service in Costa Mesa
We work with Dvele and Plant Prefab for panelized and prefabricated ADU shells on Costa Mesa lots where speed matters, and we pair those with custom interior finishes from local millwork shops for owners who want factory precision plus a hand-built feel. When a Mesa Verde project calls for architectural glass, we order Fleetwood windows and lift-and-slide doors directly and sequence the install around the framing and waterproofing, never the other way around. Our Costa Mesa crews stock common flashing, Kerdi-board, and James Hardie trim locally, so we are not waiting on a truck from LA when the marine layer moves in and a wall needs to be closed up by end of day.
Common Home Addition Contractor Problems We See in Costa Mesa Homes
- Waiting to order custom millwork until after demo. Rift-sawn white oak and custom cabinetry carry two-month lead times. When a Costa Mesa slab is open to marine-layer dampness for eight weeks waiting on cabinets, the slab sweats, the framing picks up moisture, and the drywall that goes over it can fail within a year. We order millwork at contract signing and sequence demo around the delivery date, not the other way around.
- Framing a second story to standard wind load and failing Costa Mesa’s Santa Ana review. The city wants uplift clips at every truss connection for gusty fall winds that come through the mesa. If the engineer’s calcs are standard-code and not Costa Mesa-specific, the permit stalls and the framing sits exposed. We submit wind-load details that already account for the local review standard.
- Treating an alley-facing garage as a simple conversion. In College Park and Mesa Verde, the original rear garages face 20-ft-wide alleys. When an ADU replaces that garage, the city’s replacement parking credit only applies if the owner can show the alley is too narrow for modern fire-truck turning radii. Owners who assume it is a straight conversion get a planner denial mid-permit and then pay for a redesign. We check the alley geometry before the first drawing is done.
- Leaving the original 100-amp panel and galvanized plumbing in place. Many Costa Mesa ranch homes still run on the panel and pipes they were built with in the 1960s. An addition that ties into that panel will trip, and the city will not sign off on a bathroom addition with original galvanized supply lines. We include the panel upgrade and re-pipe in the written price when the existing system is not adequate, so it is not a change order later.
Pricing for Home Addition Contractor in Costa Mesa, CA
A home addition in Costa Mesa runs $180 – $340 per square foot for a single-story room addition and $220 – $400 per square foot for a second-story addition, with bathroom additions at $35,000 – $85,000 and sunroom additions at $30,000 – $60,000 for a 150 – 250 sq ft build. Garage conversions come in at $150 – $250 per square foot, and bump-out additions run $25,000 – $55,000 for a 50 – 150 sq ft expansion. What moves the number here is not labor, it is the panel upgrade, the foundation tie-in, the plumbing re-pipe, and the custom material lead times on cabinets and glass. Call (350) 203-6060 and we’ll give you a written line-item price before anything is ordered. The estimate is free, the price is fixed before the first nail, and the guarantee is in writing before you sign.
We Also Serve Cities Near Costa Mesa
Our crews serve the neighborhoods around Costa Mesa, too. If you’re in Santa Ana, Midway City, Tustin, or Anaheim and planning a home addition, we bring the same written pricing and 365-Day Done Right Promise to your job. Whether you are working with our Home Addition Contractor team on a room addition or a full second story, the process is the same: written price first, defined arrival window, clean jobsite, and a written guarantee. If you’re in a nearby community and want to see how we work in Costa Mesa, call us and we will walk you through a recent local project.
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 Home Addition Contractor in Costa Mesa
Yes, in most cases it will. Costa Mesa’s replacement parking credit for a rear garage conversion only applies if the owner can demonstrate that the existing 20-ft-wide alley cannot accommodate modern fire-truck turning radii. That usually forces a site redesign that includes a hammerhead turn-around on the driveway approach and a fire-rated wall shift, which adds $8,000 – $20,000 to the project depending on the lot geometry. We confirm the alley width and fire-truck requirement before we draw the permit set, so the written price includes the driveway work, not a change order later. Call (350) 203-6060 and we’ll check your alley against the city’s current standard first.
We fix the price in writing before we order the millwork and glass, then we order at contract signing. Rift-sawn white oak cabinetry runs on a six-to-eight-week lead time, and Fleetwood lift-and-slide doors can run ten to twelve weeks, so the calendar is set by the suppliers, not our labor. We hold our price even if the lead time stretches, because the contract already accounts for the order date and the delivery window. The written estimate includes the cabinetry, glass, hardware, and installation labor as line items, so you know what each part costs before anything is spent.
It will not stop the addition, but it will change the scope and the price, and it needs to be addressed before the city will final the permit. A 100-amp panel on a 1960s Costa Mesa ranch cannot safely carry the added load of a new bathroom or bedroom addition, and original galvanized supply lines will eventually restrict flow and can fail when the new fixtures tie in. We include the panel upgrade and any re-pipe in the written estimate when the existing system is undersized, typically $4,000 – $8,000 for a 200-amp panel upgrade and $3,000 – $7,000 for a partial re-pipe, so it is not a door knock after framing starts.
It depends on the condition of the slab and what the engineer finds during the structural review. Some Costa Mesa slab-on-grade foundations from the 1950s and 1960s have enough bearing capacity for a second story with the addition of perimeter footings and hold-down anchors. Others have cracked or settled enough that the engineer will require selective underpinning before framing. We include a geotechnical and structural review in the planning phase and price the foundation work in the written estimate, so you are not asked for an extra check after demo starts. Call (350) 203-6060 for a free assessment of your slab and what it can carry.
We stage all moisture-sensitive materials inside or under cover from day one, and we close the shell before the marine layer can sit on open framing. Costa Mesa’s morning fog leaves a wet film on exposed lumber and a sweating slab, which is why we cover the slab every evening, schedule the Kerdi-board and waterproofing to go in against a dry substrate, and never leave open framing exposed overnight. If the weather turns and a wall cannot be closed on schedule, we tarp and ventilate, then inspect for moisture before drywall. The written guarantee covers the moisture details, so if anything fails within 365 days, we return and fix it.
Written by Russ Delmar, Owner at Lodgewick ADU Orange County, serving Costa Mesa since 2010.
Planning a home addition in Costa Mesa? Call (350) 203-6060 for a free, written estimate. We’ll give you a real price, a defined arrival window, and a written guarantee before any custom materials are ordered.
