Fast, Reliable Bathroom Remodeling Across Fontana
A full bathroom remodel on a Kaiser-era slab in Fontana typically runs $19,000 – $34,000 depending on whether we’re converting a garage bay, rebuilding a rear-block-wall bath, or adding a curbless shower for a parent moving in. That’s the honest range, and it’s the number that matters when you’re comparing bids. We’re Nate Holloway and the team at Sunstone ADU Builders. We’ve remodeled baths inside Fontana ADUs and primary homes from the 92335 tracts off Sierra to newer builds south of Summit. Call (855) 949-1913 for a free, line-item estimate, and we’ll walk the site before we quote.
Why Sunstone ADU Builders Is Fontana’s Preferred Bathroom Remodeling Company
We do ADUs as our core business, which means we understand Fontana bathroom remodels through the lens of what this city actually builds: garage conversions, rear-yard units behind RV gates, and multigenerational additions. The Bathroom Remodeling team that finishes Sunstone ADUs is the same crew that remodels existing baths in the primary home. That matters because a bathroom in a converted garage has different waterproofing, slab, and electrical constraints than a bathroom inside the house. We’ve learned those constraints block by block.
Fontana homeowners call us after plan check kicks back unpermitted patio rooms, after a garage-conversion shower starts popping stucco, or after an aging parent needs a step-in shower and the existing slab won’t cooperate. We handle the full scope under one contract, including Bathroom Remodeling in Fontana for the house side of the property while the ADU goes up. Nate Holloway leads every estimate and walks the panel, the slab, and the vent path before we price anything. That’s not a sales pitch, it’s how we avoid change orders mid-demolition.
Our Bathroom Remodeling Services in Fontana
Curbless and Step-In Shower Conversions for Multigenerational Baths
Most Fontana ADU bathrooms are built for a parent, an adult child, or a rent-paying tenant. When the end user is a parent moving in, a curbless shower is often the deciding factor. The problem is the slab. Pre-WWII and 1960s tract homes in 92335 and 92336 sit on original Kaiser-era slabs that are thin, uneven, and rarely sloped for drainage. We evaluate the slab before quoting. If the fall works, we recess the shower pan without trenching. If it doesn’t, we build a low-profile step-in shower with a Schluter pan and linear drain. We never promise curbless until we’ve checked the actual concrete.
Tile and Waterproofing for Garage-Conversion Slabs
Garage-conversion baths in Fontana get framed tight against the existing stucco wall. The common failure we see is no vapor barrier behind the framing. Shower moisture wicks through the wall assembly into the block wall and pops the stucco within a few seasons. We specify a full waterproofing system on every garage-slab bath: Schluter Kerdi membrane or a liquid-applied membrane over the shower walls, a vapor barrier between framing and exterior stucco, and James Hardie backer in wet zones. In the hot-dry Inland Empire, a vapor barrier is not optional. It’s the difference between a rental-ready bath and a mold claim.
Ventilation and Lighting Upgrades Tied to Panel Capacity
Older Fontana homes off Sierra Avenue and Foothill have undersized 100-amp panels. When we remodel a bath in these homes, we often can’t add a dedicated 20-amp circuit for a heated floor or a proper exhaust fan without first pulling a subpanel. Summer attic heat above 100°F bakes uninsulated vent ducts. Cheap builder-grade exhaust fans fail, condensation collects, and mold returns on the ceiling even after a fresh tile job. We spec insulated flex duct, a 110-CFM Panasonic fan, and a humidistat switch. If the panel is full, we quote the subpanel as a separate line item so you see it up front, not as a surprise change order.
Full Bath Remodels for Primary Homes
When the ADU bath is done, many Fontana homeowners ask us to remodel the primary bath in the house while the crew is already on site. This often includes the hallway bath in a 1970s tract home in 92337 or a master bath addition off a primary suite. We quote these as separate scopes under the same contract. That means one permit, one project manager, and one warranty. You’re not coordinating a separate bathroom contractor while the ADU framing is still open.
Rental-Ready Bath Finishes
For Fontana homeowners building a rental ADU, the bathroom is the room that sells the unit. We keep finishes durable and easy to maintain: porcelain tile, a fiberglass or solid-surface shower base in rental units, a wall-mount sink where square footage is tight. We recommend a 30-inch minimum shower opening for tenant turnover, not luxury glass enclosures. Rental-ready doesn’t mean cheap. It means surfaces a tenant can’t destroy in one lease cycle.
What happens when you call
- 1
A real person answersNo phone trees — you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Fontana
Sunstone ADU Builders is an authorized builder for Abodu and Cover service in Fontana, and we finish their interiors in-house. When we complete a bathroom inside an Abodu or Cover ADU, we stock the trim, valve, and backer brands our Fontana customers need locally, so we’re not waiting on a supply house in Ontario. We also specify James Hardie backer and fiber cement in wet zones, because Fontana’s hot-dry climate bakes cheap fiberboard, and because James Hardie holds up to moisture and wildfire-adjacent conditions better than most. For traditional builds, we use Schluter waterproofing and Panasonic ventilation. For Dvele units, we follow their factory spec and finish the bath under one contract.
Common Bathroom Remodeling Problems We See in Fontana Homes
- Moisture against the rear block wall: Bathrooms built behind the rear property line, inside an attached garage or a rear-yard ADU, get sprinkler overspray against the block wall. The stucco wicks moisture, the bottom plate rots, and the shower inside starts failing within a few seasons. We see this constantly in ZIP 92335 and 92336.
- Unpermitted patio rooms that surface at plan check: Many Fontana homeowners enclosed a patio decades ago without permits. When we pull permits for the bath remodel, the city flags the unpermitted room. We handle the correction, re-fit the GFCI circuits, and bring the vent fan to code before we set tile.
- Shallow slabs in older tracts: Kaiser-era slabs in 92335 homes are often 3.5 inches thick in spots, with no vapor barrier underneath. Waterproofing a curbless shower on that slab requires a surface-applied membrane, not just a PVC liner. We’ve seen tile fail twice on slabs where the previous contractor skipped the membrane.
- Aging panels blocking heated floors and tankless units: A 100-amp panel with no spare breaker slots can’t power a tankless water heater and a heated floor. We pull a subpanel before we rough in, and we quote it as a line item. That’s a Fontana-specific reality: the housing stock age drives the electrical cost, not the finish level.
Pricing for Bathroom Remodeling in Fontana, CA
Here are the actual ranges we quote in Fontana, ZIP codes 92335, 92336, and 92337:
- Garage-conversion bath (framing, waterproofing, shower, toilet, sink): $19,000 – $28,000
- Primary bath remodel (gut, new tile shower, double vanity, lighting): $22,000 – $34,000
- Curbless shower conversion on an existing slab: $9,000 – $14,000 depending on slab work
- Subpanel upgrade (when required): $2,500 – $4,000 as a separate line item
What moves the price: whether we’re on a slab or a wood-framed floor, whether the drain lines need rerouting, and whether the panel has capacity. We give every Fontana customer a written, line-item estimate before work starts, and we hold that number unless you change the scope. No change orders without your signature. Call (855) 949-1913 to schedule a free estimate, and we’ll walk the slab, the wall, and the panel so the quote is real.
We Also Serve Cities Near Fontana
Sunstone ADU Builders works across the western Inland Empire. We regularly remodel bathrooms in Fontana, Bloomington, Rialto, Glen Avon, and Pedley. If your property sits near the 10 or the 60 and you’re planning a garage-conversion bath or a rear-yard ADU, we’ll schedule a site visit and quote the full scope.
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 – Bathroom Remodeling in Fontana
Yes, and it’s one of the most common projects we do in ZIP 92335 and 92336. The answer depends on two things: whether the garage slab slopes enough for a curbless or step-in shower, and whether the existing panel has room for a bathroom circuit. In older Kaiser-era homes, the slab is usually flat enough for a recessed Schluter pan, but the 100-amp panel often needs a subpanel. We evaluate both before quoting. Call (855) 949-1913 for a site assessment, free.
Because sprinkler spray hits the block wall, the stucco wicks moisture, and the bottom plate rots. The bathroom inside starts failing even though the shower itself is waterproofed. We fix this by installing a vapor barrier behind the framing, sealing the exterior penetration, and using James Hardie backer in the wet zone. A bathroom built right can handle Fontana’s dry heat and the irrigation cycle.
Not always. If the slab has enough fall, we can recess a shower pan up to about an inch without trenching. If the slab is too thin or uneven, a step-in shower with a low-profile pan is the safer call. We won’t know until we open the floor. That’s why we inspect the slab before quoting a curbless conversion in Fontana.
Hot attic air bakes uninsulated vent ducts. Cheap exhaust fans fail, condensation forms, and mold grows on the ceiling even after a new tile job. We spec insulated flex duct and a 110-CFM Panasonic fan on every Fontana bath remodel. If the attic has no ventilation, we add a roof vent. It’s a $300 – $500 add that prevents a recurring mold problem.
Yes, we can, but the city will require the room to be brought to code as part of the permit. That usually means re-fitting GFCI circuits, adding a vent fan to code, and sometimes correcting the roof tie-in. We handle the correction and the remodel under one contract. Call (855) 949-1913 and we’ll tell you what the city will require before we start.
Written by Nate Holloway, Owner at Sunstone ADU Builders, serving Fontana and the western Inland Empire.