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 Fullerton
Hiring a General Contractor in Fullerton means finding someone who understands that most of the work here is not new construction. It is remodeling, adding on, and building ADUs on lots that were platted before World War II. We work in Fullerton weekly, from the historic bungalows around College Park to the ranch tracts north of Chapman Avenue, and we know what the city’s planning counter asks for before you ever sign a contract. Call us at (877) 688-9930 to talk through your project and get a straight answer about scope, cost, and timeline.
Why Square One Builders Is Fullerton’s Preferred General Contractor Company
Square One Builders has built its reputation in Fullerton on full-scope accountability. Homeowners here tell us the same thing: they are tired of calling a roofer for the roof, a cabinet company for the kitchen, and a third crew for the addition. Our Fullerton clients get one contract, one schedule, and one team that answers for every phase. Brent Calloway started the company on that principle, and it is the reason most of our Fullerton work comes from referrals in neighborhoods like the 92832 historic district and the 92835 hillside streets near the Coyote Hills.
We do not bid work we cannot manage. When a Fullerton homeowner asks us to convert a garage on a lot with a 60-amp panel and original clay sewer lateral, we tell them upfront that those systems will need upgrading before rough-in. That honesty, delivered early, is what keeps our projects on budget and our clients from feeling ambushed. Our Fullerton PGT service means response time from our Westminster office is short enough that we can usually walk a property within two business days of the first call.
Styles & brands we work with
Licensed General Contractor in Fullerton
A Licensed General Contractor in Fullerton is the legal requirement for any project that combines structural, electrical, plumbing, or mechanical work under one permit, and it is the only way to hold a single company accountable for the whole job. When you add a second story to a 1940s bungalow near the college, convert a detached garage off Nutwood Avenue into a rental unit, or remodel a kitchen down to the studs in a 92833 ranch, the city will not sign off unless the work was done under a properly licensed contractor’s permit. We pull permits, schedule inspections, and carry the project through final sign-off.
Full-Scope Remodeling
Fullerton homes built before 1960 hide things behind the walls: knob-and-tube wiring, galvanized supply lines, lath-and-plaster over hand-framed studs. A full-scope remodel means we open the wall, see what is actually there, and budget for the correction before we quote the finishes. That is the difference between a Kitchen Remodel in Fullerton priced at $14,000 – $45,000 and one that ends up costing twice the original number because nobody planned for the surprises.
Additions and ADUs
Most Fullerton additions are vertical, not horizontal. Lots are small, setbacks are fixed, and the only direction to go is up or into the old garage footprint. We scope Home Additions in Fullerton at $45,000 – $130,000 and ADU Construction at $90,000 – $220,000, and both numbers assume the panel, sewer lateral, and foundation will need work. That is not a guess. It is what we see on nearly every pre-1960 lot in this city.
Residential General Contractor in Fullerton
A Residential General Contractor in Fullerton handles the single-family home market: whole-home remodels, kitchen and bath work, additions, garage conversions, and ADUs on owner-occupied parcels. That is different from commercial contracting, and it matters because Fullerton’s building codes, historic overlay rules, and lot conditions are specific to houses, not storefronts. We know which neighborhoods trigger historic review on visible elevations, and we know how to design around it instead of fighting it after plan check.
Whole-Home Coordination
When a Fullerton homeowner wants the kitchen opened to the family room, the hallway bath converted to a walk-in shower, and a new roof over the whole thing, that is three crews, three budgets, and three schedules if you hire separate specialists. We manage it as one project. The roofing material specs, the waterproofing under the shower pan, and the beam that carries the new opening all get coordinated before demolition starts. Our brand portfolio spans GAF and CertainTeed roofing through KraftMaid cabinetry and Kohler plumbing fixtures, so selections happen in one conversation, not three showroom trips.
Older Home Expertise
Fullerton’s housing stock skews old. The Craftsman cottages and Spanish Colonials around College Park and downtown sit on pier-and-beam or shallow slab foundations. Postwar ranch tracts in 92834 and 92835 use early Romex and cast-iron waste lines that are now seventy years old. We spec materials and methods for those conditions: floor leveling where the slab has shifted, venting upgrades where the original bath fan never worked, and foundation reinforcement where a second story is going on top of a footing that was poured for one.
Trusted Brands We Service in Fullerton
We stock and install materials from manufacturers that carry long warranties and real local supply-chain support, which means we do not wait on backordered parts when a Fullerton client needs a roof tie-in or a specific cabinet line. Our roofing portfolio includes CertainTeed and Owens Corning, and we regularly spec IKO and Atlas products for Fullerton homes where fire-resistant Class A assemblies matter due to the city’s Wildland-Urban Interface along the Coyote Hills. Sourcing through national manufacturers keeps lead times predictable and gives Fullerton homeowners a paper trail for warranty claims down the road.
See the difference
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After
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AfterCommon General Contractor Problems We See in Fullerton Homes
- Undersized electrical panels. A 60- or 100-amp panel cannot carry an ADU or a modern kitchen. Upgrading to 200-amp service is usually mandatory, and it has to happen before drywall, not after.
- Original clay sewer laterals. The old terra cotta lines under College Park and downtown Fullerton crack, root-intrude, and belly over decades. Any addition or ADU that adds bathrooms triggers a lateral inspection and often a replacement.
- Small-lot setbacks and historic review. Fullerton’s older tracts were platted tight. A second-story addition or detached ADU has to respect existing setbacks, and homes in the historic core may need design review on window style, roof pitch, and street-facing elevation.
- Santa Ana wind and fire-resistance detailing. North Fullerton neighborhoods near the Coyote Hills sit in a Wildland-Urban Interface zone. Class A roofing, ember-resistant vents, and defensible-space planning are not optional add-ons on these streets; they are code-driven requirements we build into the scope.
Pricing for General Contractor in Fullerton, CA
We quote Fullerton work with line-item ranges, not vague allowances. The table below reflects what we have priced on actual Fullerton permit sets over the past several years. Your number lands inside the range depending on lot access, panel and sewer upgrades, and finish level.
| Project | Typical Fullerton Range |
|---|---|
| ADU Construction | $90,000 – $220,000 |
| Home Addition | $45,000 – $130,000 |
| Garage Conversion | $30,000 – $80,000 |
The biggest wildcard in Fullerton is not the finish material; it is what is under the ground and behind the panel. An old clay lateral replacement can add $8,000 – $15,000 before rough-in. A panel upgrade from 60 to 200 amps typically adds $3,500 – $6,000. We identify these line items during the scoping walk, not after the contract is signed. Call (877) 688-9930 and ask for a free estimate. We will walk the property, check the panel, and give you a written quote that covers what we actually see.
We Also Serve Cities Near Fullerton
Square One Builders works throughout North Orange County, not just within Fullerton city limits. We regularly serve General Contractor in Fullerton projects in Anaheim, La Habra, Placentia, and Brea, and our Westminster office keeps us close enough to walk properties and pull permits across the region without long delays.
Serving Fullerton, CA — Our Local Coverage Area
We’re based in the Fullerton 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 Fullerton
Most acreage parcels in and around 92835 are under City of Fullerton jurisdiction, not Orange County, which means city planning counter review, city setbacks, and city inspection. Assuming county rules will get your plan check kicked back. Call (877) 688-9930 and we will check the specific parcel before you commit to a design.
Septic systems and wells have legal setback distances from any new structure, and violating them means moving the building or the system. We verify septic and well locations on the site plan before you buy materials, because discovering a setback violation after the foundation is poured creates a change order no homeowner should have to absorb.
Because most Fullerton garages were built when the house ran on a 60- or 100-amp panel, and adding a dwelling unit with a kitchen and bath pushes the calculated load past what the old panel can legally carry. The upgrade to 200-amp service happens before rough-in and is a line item we show you up front, not a surprise order midway through.
We scope delivery and mobilization separately for large-lot and hillside properties in 92835, where the driveway may be long, steep, or gated, and the nearest material yard is a haul through city traffic. We plan concrete and framing deliveries around access constraints, and we build the haul cost into the bid so there is no allowance surprise later.
Open lots and hillside parcels in Fullerton drain toward the existing structures, not away from them, unless someone regrades. We check the fall lines during the scoping walk, set foundation elevations to move water away from the new build, and include drainage correction as a bid line item rather than hoping the inspector will not notice ponding after the slab is down.
Written by Brent Calloway, Owner at Square One Builders, serving Fullerton and North Orange County since the company’s founding.
Ready to get a real number on your Fullerton project? Call (877) 688-9930 and schedule a free estimate. We will walk your property, check the existing systems, and give you a written line-item quote before you ever sign a contract.