Fast, Reliable Garage Conversion ADU Across San Bernardino
A garage conversion ADU in San Bernardino typically runs $95,000-$165,000 all-in, from measured drawings through final inspection, with most projects taking 6-10 months depending on utility complexity. We’re the Garage Conversion ADU team at Ellery ADU Studio, and we coordinate design, permit sets, and construction from our Inland Empire office for San Bernardino homeowners specifically. Dispatch and scheduling are handled locally for the San Bernardino market, not routed through a coastal call center. If you’re on a flatland block near Mount Vernon Avenue, up in the foothill zones near Cajon Boulevard, or anywhere between the I-10 and I-215 corridors, we know the lot constraints, the alley widths, and the building department’s current review timelines. Call (951) 476-1467 to schedule your free estimate.
Why Ellery ADU Studio Rialto Is San Bernardino’s Preferred Garage Conversion ADU Company
We’ve designed, permitted, and built ADUs across San Bernardino since 2015 - the year California’s ADU laws shifted - and our permit sets are the core product, not an afterthought handed off to a third-party drafter. Every San Bernardino project receives a written price before any work starts, per Haven Standard Clause 1. No “call for a quote.” The number is on the page, or it’s in your hands at the consultation.
Our crews are background-checked, uniformed, and state-licensed; the license number appears on every contract and every page of this site. Clients in San Bernardino receive a documented photo record on every visit - what we found, what we did, not a summary of how it felt. Under Clause 5 (No Surprises), the scope locks at signing; no door-side upsells, no scope creep.
The 365-Day Done Right Promise backs every San Bernardino conversion in writing: if the finished ADU isn’t built to the permitted drawings, we make it right. A live person answers calls 24/7 - no voicemail queue, no callback promise that doesn’t materialize. And if you already have a written estimate from another firm, we offer a Free Second Opinion.
Our Garage Conversion ADU Services in San Bernardino
Attached Garage Conversion
Attached garages dominate San Bernardino’s 1950s-1970s ranch stock, and they’re the most common conversion target we see. These structures share a wall with the main house, so party-wall notice is mandatory - we post to neighbors two weeks ahead, document the notice, and schedule demo so shared stucco patches happen in a single sequence. On the Westside and near downtown, alley access is often too narrow for material drops; we price staging alternatives into the quote from day one, not as a change order when the dumpster doesn’t fit.
Detached Garage Conversion
Detached two-car garages on San Bernardino’s 7,000-10,000+ sq ft lots convert cleanly when the slab is intact and the roof structure can carry insulation and mechanicals. The catch is almost always power: the original 100-amp panel serving the main house cannot carry a second dwelling unit, so we pull a 200-amp service upgrade as a baseline line item in every detached conversion quote. We also spec James Hardie ignition-resistant cladding on foothill-adjacent parcels where Very High Fire Hazard Severity Zone requirements apply.
Garage JADU
A Junior ADU - under 500 sq ft, sharing bathroom or kitchen facilities with the main house - is the fastest path to rental income on a tight San Bernardino lot. We regularly convert half a two-car garage into a JADU while preserving storage or workshop space in the remainder. The 200-amp panel upgrade still applies, but the reduced mechanical load can sometimes simplify the electrical scope. We handle the JADU-specific San Bernardino zoning verification, including owner-occupancy requirements and the separate exterior entrance.
Garage Partition & Bathroom Add
Some San Bernardino homeowners want a partial conversion: a studio space with bathroom, not a full kitchen, or a partitioned layout that keeps one bay as garage. We draw the partition as a rated assembly in the permit set, not as an afterthought, and we spec Tuff Shed modular components where the existing structure needs supplemental weatherproofing. Every partition includes the documented photo record showing before, during, and rated-assembly completion.
Carport Conversion
Carport conversions are less common in San Bernardino’s garage-heavy stock, but they appear in pockets of 1960s infill near Base Line and the university area. These require full enclosure, slab evaluation, and often foundation augmentation where the carport was built as a non-structural canopy. We price the structural and envelope work separately so you see where the money goes.
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.
Before
AfterTrusted Brands We Coordinate in San Bernardino
Ellery ADU Studio specifies and coordinates prefab and modular systems from Abodu, Cover, Tuff Shed, and James Hardie within the same single-contract framework - no designer-versus-builder blame gap. For San Bernardino’s climate, we default to James Hardie fiber-cement siding on new envelope work for its fire-resistance rating and 115°F thermal stability, and we coordinate Abodu or Cover units where a full teardown-and-replace makes more sense than retrofitting a failing structure. Every brand selection is documented in the permit set with spec sheets and installation sequences, so the building department and the tenant both know what was built.
Common Garage Conversion ADU Problems We See in San Bernardino Homes
- The 100-amp panel trap. Nearly every pre-1980 San Bernardino home we inspect still has its original 100-amp main panel. The city will not approve a second dwelling unit on that service. We catch this in the first site visit and price the 200-amp upgrade as a visible line item, not a mid-project surprise.
- HVAC underspec for valley heat. San Bernardino hits 108-115°F regularly, and Santa Ana winds out of Cajon Pressurize every gap in the envelope. We spec 115°F-rated mini-splits with tight duct sealing and R-13 minimum wall insulation - the minimum for rentability, not just code compliance.
- Galvanized supply lines. Original water supply in 1950s-1970s San Bernardino ranches is often galvanized steel, which the city won’t accept for a new dwelling unit. We replace with PEX or copper and pressure-test before rough inspection.
- Alley staging conflicts. Narrow alleys on the Westside and near downtown can’t accommodate dumpsters or material drops. We plan hand-carry staging, driveway laydown, or crane-set modular components from the start - priced, not improvised.
Pricing for Garage Conversion ADU in San Bernardino, CA
Garage conversion ADUs in San Bernardino typically run $95,000-$165,000 all-in, drawings through final inspection. Attached garage conversions fall in the $95,000-$130,000 range; detached conversions with utility trenching and standalone mechanical run $120,000-$165,000. Garage JADUs, being smaller and sharing some systems, typically land at $75,000-$110,000.
Every quote includes the 200-amp service upgrade as a visible line item - $4,500-$8,500 depending on trench length and SCE coordination - because it hits virtually every San Bernardino project. HVAC spec for valley-floor heat adds $3,000-$6,000 over coastal baseline. Fire-hazard-zone cladding on foothill parcels: $2,500-$5,000 additional.
Under Haven Standard Clause 1, the written price arrives before any work starts. The scope locks at signing per Clause 5. No change orders unless you change the scope. Call (951) 476-1467 for your free estimate.
We Also Serve Cities Near San Bernardino
Our crews work throughout the Inland Empire, including Garage Conversion ADU in San Bernardino and surrounding cities: Rialto, Redlands, Riverside, and Fontana. Each city’s building department has its own review timeline and inspector preferences; we maintain separate permit-tracker files for each jurisdiction so your project doesn’t get delayed by paperwork confusion.
Serving San Bernardino, CA - Our Local Coverage Area
We’re based in the San Bernardino 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 - Garage Conversion ADU in San Bernardino
The original 100-amp panels in San Bernardino’s 1950s-1970s housing stock were sized for a single household’s load, and the building department will not sign off on a second dwelling unit that shares an undersized service. We verify ampacity at the first site visit and price the upgrade as a visible line item in every quote. Call (951) 476-1467 for an exact scope and written price - estimates are free.
Yes. San Bernardino requires party-wall notice for any work affecting a shared wall, and we post that notice two weeks ahead, documented with date-stamped photos for your file. On the Westside conversion off Mount Vernon Avenue, we notified the neighbor early, scheduled the shared-wall demo and stucco patch as a single sequence, and had zero complaints. The permit set includes the party-wall detail; the building department checks it at plan check.
Narrow alleys on San Bernardino’s older flatland blocks often can’t fit dumpsters, material drops, or crane setups, so we price staging alternatives - driveway laydown, hand-carry through side yards, or modular crane-set from the street - as explicit line items before work starts. We survey access at the first visit and document the staging plan in the permit set. Ignoring alley limits mid-project triggers code-enforcement complaints; we don’t ignore them. Call (951) 476-1467 to schedule the access survey.
We spec 115°F-rated mini-split systems with tight duct sealing and minimum R-13 wall insulation, plus ember-resistant venting on foothill parcels in Very High Fire Hazard Severity Zones. Standard coastal HVAC specs fail here; we’ve seen conversions with undersized units become unrentable ovens by July. The spec is written into the permit set, not left to the installer’s discretion. Call (951) 476-1467 for the full mechanical scope.
Yes, if the remaining garage space meets San Bernardino’s minimum dimension and access requirements for the use you want to keep. We draw the partition as a rated assembly in the permit set, verify the JADU’s separate exterior entrance, and confirm owner-occupancy compliance. The 200-amp panel upgrade still applies, but the reduced load can simplify electrical scope. Call (951) 476-1467 for a site-specific feasibility check - estimates are free.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving San Bernardino since 2015.