Fast, Reliable Bathroom Remodeling Across Montclair
Bathroom remodeling in Montclair, CA typically runs $18,000 – $42,000 for a full gut-and-replace, with garage-conversion ADU bathrooms landing between $22,000 – $35,000 when fire-rated walls and foundation retrofits are factored in. Most Montclair projects take 3 – 6 weeks once permits clear. We’re Bungalow ADU Builders, led by Nate Calloway, and we handle bathroom remodels across Montclair from the 91763 zip code out to the neighborhoods near the 10 and 60 freeways. Call (866) 730-4828 for a free estimate and a line-item quote that includes the property-line wall work other contractors skip.
Montclair’s housing stock creates a very specific kind of bathroom project. Post-WWII single-story tract homes, rear-alley garages, and narrow 50 – 60 ft lots mean most remodels here happen inside existing footprints or converted garage ADUs. That changes the plumbing, the framing, the fire-rating, and the price. We know those conditions because we’ve worked them on blocks from Monte Vista Avenue down to Ramona Park.
Why Bungalow ADU Builders Is Montclair’s Preferred Bathroom Remodeling Company
Montclair homeowners call us for bathroom work because the company was built around the exact housing pattern this city has: small lots, stucco tract homes, detached rear garages. Our Bathroom Remodeling team understands that a bathroom inside a converted Montclair garage is not the same as a bathroom inside the main house. The wall facing the alley sits on the property line. The slab underneath was poured in 1962 with no footing depth to speak of. The window openings face wind exposure that matters when Santa Ana season hits.
Nate Calloway started Bungalow ADU Builders to fix the handoff problem. General contractors frame the ADU, then call a different crew for the bathroom, then a third for the kitchen. That’s three sets of assumptions, three schedules, three markups. Our crews handle the ADU shell and the interior finishes under one roof. From foundation to finished bathroom, one team. That coordination matters more in Montclair than in most cities because the rear-alley garage pattern forces so much upfront structural work before finish work can begin.
We also know the local permitting path. Montclair’s pre-1970 slab-on-grade homes mean sewer tie-ins go around original main-line laterals, not through them. A plumber who has never worked a 1950s Montclair lot will discover that at the worst possible moment. We plan for it in the estimate.
Our Bathroom Remodeling Services in Montclair
We focus on four core bathroom remodeling scopes in Montclair, each with a different permitting and pricing profile.
Full Bathroom Gut and Replacement
For homeowners on Central Avenue, Howard Street, or the neighborhoods around Montclair High School, a full gut means removing everything to the studs, replacing the shower pan or tub, updating the valve and drain, and rebuilding with waterproofed surrounds. In Montclair’s 1950s – 70s homes this often reveals galvanized drain lines that have rusted from the inside out. We budget for replacement rather than discovering it mid-project and handing you a change order. Expect $22,000 – $42,000 depending on fixtures and whether the floor joists need reinforcement after 60 years of moisture exposure.
Garage-Conversion ADU Bathroom
This is the project type we understand better than any general bathroom contractor serving Montclair. The rear-alley garages that sit on so many 91763 lots are the natural ADU footprint, but the bathroom inside that converted space has code obligations a normal bathroom never faces. The wall on the alley side is a property line wall. Montclair requires a 1-hour fire-rated wall assembly, typically sheathing plus rock wool insulation plus rated drywall, before any tile or vanity can be installed. We frame that wall as part of the remodel scope, not as a separate surprise line item. Budget $24,000 – $38,000 when foundation retrofit and fire-rated assembly are included.
Bathroom Refresh Without Moving Plumbing
If your Montclair bathroom just needs new tile, a new vanity, a glass shower enclosure, and lighting without relocating the toilet or shower drain, the project is faster and cheaper. We see this a lot in the original hall baths of the tract homes between Ramona Avenue and the Montclair Plaza area. Same footprint, new finishes. Expect $12,000 – $20,000, permits pulled, two to three weeks on site.
Wet-Area Repair and Waterproofing
Montclair’s hot, dry summers followed by occasional winter downpours create a particular failure pattern: grout cracks from thermal expansion, water seeps into the substrate, and the failed area hides until the tile starts to lift. We tear out the affected wet area, inspect the framing behind it, replace any compromised lumber, and rebuild with bonded waterproofing membrane. This is repair work first, remodeling second. Cost runs $4,000 – $9,000 for a typical 3-piece tub-shower surround repair.
What happens when you call
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A real person answersNo phone trees — you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Montclair
We source ADU and bathroom products from a defined roster rather than whatever the supply house has in stock. For Montclair projects we frequently specify James Hardie fiber-cement sheathing on exterior-facing bathroom walls, especially the alley-side property line walls on garage conversions, because it carries the fire-rating documentation inspectors and insurance adjusters want to see. For the ADU shell itself we work with Boxabl, Plant Prefab, and Tuff Shed systems depending on the lot and budget, but the bathroom inside is always built to local code. We also keep common fixture and valve replacement parts sourced so a Montclair repair doesn’t stall waiting on a backordered trim kit.
Common Bathroom Remodeling Problems We See in Montclair Homes
- Property-line fire wall missing behind the bathroom. Garage-conversion ADUs on alley-facing Montclair blocks require a 1-hour fire-rated wall on the property line. Skipping it fails inspection and gives an insurance adjuster a reason to deny a claim after a fire or wind event.
- Shallow footing depth from the original garage slab. Many 1950s – 70s Montclair garage slabs were poured without frost-depth footings. A bathroom remodel on that slab leads to cracked floor tile and plumbing movement after the first winter rain. We retrofit before we tile.
- Wind-load failures at bathroom windows and vents. Santa Ana wind events hit the rear of Montclair homes hard, especially detached ADUs with west or north exposure. Standard off-the-shelf window flashing and vent caps fail. We specify wind-rated assemblies and document installation with photos.
- Old galvanized drain lines in slab-on-grade homes. Montclair’s pre-1970 homes often have galvanized steel waste lines embedded in the slab. A remodel that doesn’t camera-inspect the line first can result in a beautifully tiled bathroom connected to a drain that collapses six months later.
Pricing for Bathroom Remodeling in Montclair, CA
Here’s what Montclair homeowners should expect to pay in 2026. A cosmetic refresh in the original hall bath: $12,000 – $20,000. A full gut-and-replace in a primary bathroom: $22,000 – $42,000. A garage-conversion ADU bathroom with fire-rated wall and foundation retrofit: $24,000 – $38,000. Wet-area repair only: $4,000 – $9,000.
What moves the number: whether you’re moving plumbing, whether the wall on the alley side is on the property line, whether the slab needs footing work, and the fixture tier you choose. A cheap quote that omits the fire-rated wall or the footing retrofit is not cheaper; it’s incomplete. Our quotes are line-item, fixed-price, and include the permit and the inspection. Call (866) 730-4828 to schedule your free estimate.
We Also Serve Cities Near Montclair
Our crews work every week in Montclair and the surrounding west Inland Empire cities. If your property is in Claremont, Ontario, Upland, or La Verne, the same permit knowledge and rear-lot garage experience applies. The housing stock is similar; the code requirements are not always identical. We know the differences.
Serving Montclair, CA — Our Local Coverage Area
We’re based in the Montclair 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 Montclair
Yes, and this is the single most common point of failure in Montclair ADU bathroom projects. When a detached rear garage is converted, the wall facing the alley sits on or near the property line. Montclair code requires a 1-hour fire-rated wall assembly on that side, meaning rated sheathing, insulation, and drywall layers that carry documented fire-resistance ratings before any bathroom finishes go up. A standard framed wall with standard drywall fails inspection. Call (866) 730-4828 for a quote that includes the rated assembly, not a change order for it later.
Montclair’s ADU bathroom windows and exterior wall penetrations must meet the same wind-load requirements as the main dwelling, and in practice that means windows and vents on rear and side walls of detached ADUs need to be specified for exposure B or C depending on the lot’s proximity to open space. Santa Ana events regularly produce sustained winds that test marginal installations. We specify and install wind-rated window flashing and vent caps, and we photograph the installation before the wall is closed. That documentation matters when an insurance claim follows a wind event.
Documented compliance is the difference between a paid claim and a denied one. If a bathroom remodel includes a fire-rated property-line wall and wind-rated window assemblies, and you have photos and inspection records proving it, an insurance adjuster has far less room to deny a fire or wind claim. The alternative, an unpermitted remodel or a missing fire-rated wall, hands the adjuster a clean denial. We document every assembly before closing the wall, and we give you the file. On a block off Holt Boulevard, we converted a detached rear garage into an ADU bathroom; the original slab lacked footing depth, so we retrofitted the foundation and framed a 1-hour fire-rated wall along the alley property line using James Hardie sheathing and rock wool insulation. When a Santa Ana wind claim was filed later, the homeowner’s adjuster accepted the compliance photos without argument.
Because most 1950s – 70s garage slabs in Montclair were poured as a simple concrete pad with no perimeter footing, no frost depth, and no reinforcement. When you add the weight of a tiled bathroom floor, a shower, and a vanity, the slab moves. Hairline slab cracks become plumbing leaks at the p-trap and waste connection. The fix is a perimeter footing retrofit, installed before the bathroom is framed or tiled. Skipping it saves money in the quote and costs far more when the tile cracks and the drain separates after the first winter rains. Call (866) 730-4828 and we’ll check slab condition as part of the free estimate.
A compliant quote for a Montclair ADU bathroom should show line items for: the property-line fire-rated wall assembly (if the bathroom is on the alley side), the foundation or footing retrofit if the original garage slab lacks depth, wind-rated window and vent flashing, the permit fee and inspection schedule, and waterproofing of the wet area. A quote that does not show these items is not a complete quote. It’s a number designed to get a signature before the change orders start. We provide fixed-price, line-item quotes with no changes unless you change the scope. Schedule your free estimate at (866) 730-4828.
Written by Nate Calloway, Owner at Bungalow ADU Builders, serving Montclair since the company’s founding.