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 Fontana
Adding a room, a second story, or a garage conversion in Fontana means dealing with a specific set of local rules that most general contractors never see until they’re standing in your front yard holding a stop-work order. We know the Fontana plan check process, the sprinkler mandates, the parking replacement triggers, and the way summer heat loads change electrical specs. Call (831) 292-4191 and talk to Russ Delmar about what you want to build. You’ll get a real conversation and a written price before any work starts.
Our crews serve Fontana from the Inland Empire office, so scheduling and material runs stay local. We’ve built additions in Sierra Lakes, Hunter’s Ridge, and the older downtown grid where 1950s ranch homes sit on lots that were platted before modern setback rules existed.
Why Lodgewick ADU Riverside Is Fontana’s Preferred Home Addition Contractor Company
We’re the ADU and home addition arm of the Kingswell family of home-service companies, established in 2010 and run here by Russ Delmar. Every Fontana project operates under The Kingswell Guarantee: a written price before work begins, a defined arrival window, a clean job site, and a written guarantee on every job. If something isn’t right within 365 days, we come back and make it right. That commitment is in writing before a single nail is driven.
Fontana homeowners have told us the same story many times: a contractor quoted one number by phone, then changed it at the door. Or a crew showed up without uniforms, without a written scope, and left a mess. We don’t work that way. Background-checked, uniformed technicians arrive in the window we gave you. Calls are answered by a live person, 24/7, not a voicemail loop.
We work hands-on with leading prefab brands like Abodu, Boxabl, and Dvele, and we know how to match those systems to Fontana’s specific lot patterns and setback rules. Whether you want a detached unit in the backyard or a bump-out off the kitchen, we’ll tell you in plain English what the city will require and what it will cost.
Bathroom Addition Contractor in Fontana
A Bathroom Addition Contractor in Fontana is what you need when your single-bathroom ranch home can’t keep up with a growing family, or when a new bedroom addition creates a demand that the existing plumbing can’t handle. Adding a bathroom to a Fontana home typically runs $35,000 to $65,000 depending on whether you’re adding to existing slab plumbing or running new drain lines across a crawlspace, and whether the city requires a separate ventilation circuit or fire sprinkler tie-in. The plan check process in Fontana is strict now, and bathroom additions on older downtown lots often trigger a setback review that newer tract homes don’t face.
Plumbing Runs and Slab Conditions
Post-1990 tract homes in Fontana are mostly slab-on-grade, which means a bathroom addition costs more to plumb than a house with a crawlspace where you can run lines underneath. We scope the actual drain route before quoting so the written price accounts for concrete cutting, not a surprised change order later.
Sewer Capacity and Older Lines
The older ranch homes near downtown Fontana often have cast-iron drain lines that were sized for one bathroom. Adding a second full bath means verifying the lateral can handle the flow, and sometimes means a partial line replacement. That’s the kind of thing we flag during the estimate, not after demolition starts.
Bedroom Addition Contractor in Fontana
A Bedroom Addition Contractor in Fontana handles everything from a single ground-floor bedroom bump-out to a full second-story addition over an existing tract home. In Fontana, a bedroom addition typically runs $180 to $320 per square foot, so a 200-square-foot bedroom lands between $36,000 and $64,000. The spread comes down to foundation type, roof tie-in, and whether the city’s updated setbacks require you to move the addition further from the property line than the original house sits. That last point catches out-of-town contractors constantly, because Fontana has tightened setback enforcement in the last decade even on infill lots that were originally platted under looser rules.
Second Story Additions on Truss Roofs
Many Fontana tract homes built after 1990 use engineered truss roofs, not stick-framed rafters. A second-story bedroom addition means cutting into that truss system and installing new beams and headers. We spec the structural engineering before quoting, so your written price covers the actual scope.
Bedroom Additions That Trigger Sprinkler Upgrades
Fontana’s plan check now requires fire sprinklers in many addition scenarios. If your project adds conditioned square footage beyond certain thresholds, the city may require extending the home’s sprinkler system or adding a new riser. We catch that in the plan review stage and give you a real number up front, because finding out mid-project means a five-figure change order.
Trusted Brands We Service in Fontana
We work regularly with prefab and panelized systems from Cover, Dvele, Mighty Buildings, and Boxabl, and we spec James Hardie siding on many Fontana additions because it holds up to the inland heat and keeps its finish through Santa Ana wind seasons. When you choose a prefab addition, we handle the foundation, the utility connections, the city plan check coordination, and the final finish work. Our familiarity with these brands means we can give you a firm number faster than a contractor who has to learn the system from scratch on your dime.
Common Home Addition Contractor Problems We See in Fontana Homes
- Jurisdiction confusion on acreage lots. Fontana has pockets of parcels that sit on the city-county line. Homeowners assume San Bernardino County rules apply because the lot looks rural, but the city of Fontana actually has jurisdiction and requires fire sprinklers in the addition. A stop-work order halfway through the job is expensive.
- The uncovered parking replacement rule. Converting a garage into a bedroom or bathroom usually works, but if the original single-car bay is too narrow for a legal parking space, Fontana requires a new concrete parking pad in the front yard or side yard. Out-of-town builders miss this, and the homeowner eats an unplanned concrete scope.
- Summer AC loads and undersized panels. A Fontana addition built without accounting for a separate subpanel often ends up with the existing electrical panel maxed out just as temperatures push past 100°F. Then the AC trips breakers and the new room can’t hold temperature. We scope the panel load before we quote.
- Grading and drainage on open lots. Lots that look flat often have a subtle slope that matters once a pad is cut. Fontana’s stormwater and setback rules can require a retaining wall and an engineered swale to make the addition legal. We walk the lot and check the grade before the written price goes out.
Pricing for Home Addition Contractor in Fontana, CA
Here’s what we see in Fontana as of 2025. A bathroom addition runs $35,000 to $65,000. A bedroom addition runs $180 to $320 per square foot. A second-story addition starts around $250 per square foot and goes up from there depending on truss work and structural scope. Garage conversions into living space run $95,000 to $150,000 when you include the parking replacement, electrical upgrade, insulation, and the city’s sprinkler mandate. Prefab additions from Cover or Boxabl can lower the framing cost but add crane, delivery, and site preparation line items. Every quote from us is a written price, before work starts. Call (831) 292-4191 for a free estimate.
We Also Serve Cities Near Fontana
Our crews cover the whole Inland Empire corridor around Fontana, including Rialto, Mira Loma, Riverside, and Ontario. If you’re on a parcel that straddles the Fontana-Rialto line or you live in a county pocket surrounded by city, we can clarify the jurisdiction before you spend money on plans. Our Home Addition Contractor team handles the full scope, and we know the Fontana market cold.
Serving Fontana, CA - Our Local Coverage Area
We’re based in the Fontana 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 Fontana
No. Fontana has many parcels over an acre that are still inside city limits, and those projects go through the City of Fontana’s plan check process, which is stricter than the county’s on sprinklers and setbacks. The county may still review the septic system if the parcel isn’t connected to city sewer. Call (831) 292-4191 and we’ll check your exact parcel before you pay for plans.
Only if the addition removes or converts an existing garage bay. The rule applies when the original garage is too narrow for a legal parking space under current code. Then the city requires a new concrete parking pad elsewhere on the lot. We flag this during the estimate, because it adds $4,000 to $8,000 to the project. Call (831) 292-4191 for an exact read on your garage.
For anything larger than a small bump-out, yes. Fontana’s summer temperatures regularly exceed 100°F, and a new bedroom or bathroom with its own AC unit typically requires a dedicated subpanel. If the existing panel is already near capacity, you may also need a main panel upgrade. We do a load calculation during the estimate so the price is real, not a guess. Call (831) 292-4191 to schedule a site walk.
A prefab unit from Abodu or Cover arrives as a factory-built module. You save framing time and weather delays, but you add crane delivery, site prep, and utility connection line items. A stick-built addition gives more design flexibility and often fits Fontana’s odd lot shapes better. Both get the same written price guarantee. Call (831) 292-4191 and we’ll price both options for your lot.
The three big ones: the uncovered parking replacement rule, the fire sprinkler requirement, and the structural upgrade needed on older non-conforming garages. Fontana’s plan check is strict now, even though the city was historically permissive. A local specialist knows which retrofits will be triggered before the plans go in. Call (831) 292-4191 for a free estimate and a written scope, all in plain English.
We scoped a detached addition on a post-1990 tract lot in Fontana’s Sierra Lakes neighborhood, where the homeowner wanted to convert an over-garage bonus room. The original truss roof had no provision for a separate living unit, so we specified a James Hardie panelized addition with a dedicated 100A subpanel, and negotiated the county’s well setback and septic reserve lines before finalizing any square footage because the lot backed up to unincorporated county land. That’s the kind of thing that only shows up on a real site visit.
Russ Delmar runs the Fontana team, and he answers questions directly. No script, no pressure. Call (831) 292-4191 for a free estimate and we’ll give you a written price before any work starts, a real arrival window, and the 365-Day Done Right Promise in writing.
Written by Russ Delmar, Owner at Lodgewick ADU Riverside, serving Fontana and the surrounding Inland Empire since 2010.
