Fast, Reliable Garage Conversion ADU Across Santa Ana
A garage conversion ADU in Santa Ana typically runs $85,000-$165,000 all-in, from as-built drawings through final inspection, with most projects falling in the $110,000-$140,000 range for a standard detached single-car conversion. We’re Nadia Ellery’s team at Ellery ADU Studio, and we’ve been handling Santa Ana’s dominant ADU project type since 2015: not clean-slate builds, but the legalization of decades-old unpermitted casitas and converted garages under California’s SB 897 amnesty pathway. Dispatch and scheduling are coordinated from our Los Angeles office, but our crews serve Santa Ana locally and know the difference between a westside bungalow off Bristol Street and a central flat near Memorial Park. Call (657) 567-6590 to schedule your free estimate.
Why Ellery ADU Studio Garden Grove Is Santa Ana’s Preferred Garage Conversion ADU Company
Santa Ana homeowners don’t need another contractor who treats their 1950s garage like a blank slate. They need a design-build studio that starts with what is actually there. Our Garage Conversion ADU team has produced as-built drawings and permit sets for more than 900 ADUs since 2015, and a significant share of those have been SB 897 legalizations in Santa Ana’s older neighborhoods.
Our Santa Ana clients receive a written price before any work starts, per Haven Standard Clause 1. No “call for a quote.” No allowance ranges that balloon once walls open. The price you sign is the price you pay, with any surprises priced and approved in writing before we touch them, under Clause 5 (No Surprises).
Every visit produces a documented photo record. Every project carries our 365-Day Done Right Promise in writing. And when you call (657) 567-6590, a live person answers, 24/7.
Our Garage Conversion ADU Services in Santa Ana
Detached Garage Conversion
This is the single most common project we handle in Santa Ana. The city’s 1940s-1960s housing stock is packed with detached single-car garages on 5,000-6,500 sq ft lots, many already serving as informal casitas for extended family. Our job typically starts with as-built drawings for the Building & Safety Division, not a foundation pour. We assess the existing slab, frame, and utilities, then build the permit set around what can be legalized and what must be upgraded to meet Title 24 energy compliance.
Garage Partition & Bathroom Add
Some Santa Ana homeowners don’t need a full standalone ADU. They need a partitioned garage with a bathroom and kitchenette for a family member, with the remaining space kept for storage or parking. These projects still trigger SB 897 compliance if the structure was unpermitted, and they still require the same electrical and plumbing upgrades we see on full conversions. We handle the partition design, the permit set, and the build as a single contract at a single written price.
Garage JADU
A Junior ADU is owner-occupied and limited to 500 square feet, but it’s often the fastest path to legalizing an existing Santa Ana structure. The JADU route can bypass some of the parking replacement requirements that snag full ADU conversions on tight central-city lots. We evaluate whether your garage qualifies for the JADU pathway during our initial site visit and document the findings in writing.
Attached Garage Conversion & Carport Conversion
Attached garages in Santa Ana’s bungalow and ranch stock share the same problems as detached units: 60-100 amp panels, original galvanized supply lines, and framing that predates modern seismic codes. Carport conversions are less common but viable where the existing slab and posts can be enclosed to ADU standards. Each project type gets its own permit set and its own written price, with no designer-versus-builder blame gap.
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 Service in Santa Ana
We specify and coordinate prefab and modular systems from Abodu, Cover, and James Hardie within the same single contract that covers your design, permitting, and build. For Santa Ana’s SB 897 legalizations, prefab isn’t always the right fit, but where a clean-slate detached ADU makes sense, we size and specify the unit, handle the foundation and utility tie-ins, and manage the finish integration. Every brand we work with is backed by the same Haven Standard documentation: written price, photo record, and 365-Day Done Right Promise.
Common Garage Conversion ADU Problems We See in Santa Ana Homes
- Electrical systems that won’t pass modern ADU standards. We routinely open garages in the central-westside and find 60-amp service with cloth-wrapped or knob-era wiring. The city won’t finalize an ADU permit until the panel is upgraded to 200 amps and circuits are brought to current code. We price this as a line-item allowance before work starts, not a mid-project surprise.
- Waterproofing that was never installed. Alley-side slabs in Santa Ana’s older neighborhoods often lack proper dampproofing where the block wall meets the foundation. By the time we open the walls, moisture has compromised the sill plate and triggered mold remediation. We document the condition with photos, price the remediation in writing, and don’t proceed until you approve.
- Undersized framing that fails as-built review. Santa Ana’s unpermitted casitas were built to carry a roof, not a ceiling full of insulation, mechanicals, and drywall. Once we produce as-built drawings, the Building & Safety Division often flags rafter spacing or header sizing that doesn’t meet current span tables. We engineer the fix, price it, and pull the revised permit set.
- Title 24 energy compliance gaps. Even a well-built unpermitted structure won’t meet California’s energy code without ductless mini-split specification, high-efficacy lighting, and proper envelope sealing. Santa Ana’s mild climate means cooling dominates heating loads, but west- and south-facing units still need careful load calculation to handle summer heat gain against block walls.
Pricing for Garage Conversion ADU in Santa Ana, CA
Garage conversion ADUs in Santa Ana typically run $85,000-$165,000 all-in, with most homeowners landing between $110,000 and $140,000 for a standard detached single-car legalization. Attached conversions tend toward the lower end of that range where the existing structure is sound and utility runs are shorter. Carport conversions and full rebuilds push higher, especially where foundation work is required.
What moves the number: panel and circuit upgrades ($8,000-$18,000), cast-iron drain replacement ($4,000-$9,000), slab remediation and waterproofing ($3,000-$12,000), Title 24 energy package including ductless mini-split ($5,000-$11,000), and fire-resistant exterior finishes with ember-resistant venting ($4,000-$8,000) for Santa Ana wind season compliance.
Every project is quoted with a written price before any work begins, per Haven Standard Clause 1. No verbal estimates. No “we’ll figure it out as we go.” Call (657) 567-6590 for your free estimate.
We Also Serve Cities Near Santa Ana
Our crews work throughout central Orange County, including Garage Conversion ADU in Santa Ana and the surrounding cities of Tustin, Orange, Garden Grove, and Costa Mesa. Each market has its own housing stock and permit path, and we adjust our permit sets accordingly.
Serving Santa Ana, CA - Our Local Coverage Area
We’re based in the Santa Ana 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 Santa Ana
Santa Ana’s dominant project type is SB 897 legalization, not clean-slate construction. A typical Santa Ana garage has 60-amp service, cloth wiring, no waterproofing, and unpermitted framing that must be documented, upgraded, and brought to Title 24 compliance before the city will sign off. Irvine’s newer stock rarely carries these legacy conditions, so its conversions move faster with fewer surprises. Call (657) 567-6590 for a written quote on your specific Santa Ana property.
We find three things consistently: electrical systems that predate modern grounding and won’t pass ADU inspection, waterproofing that was never installed on the alley-side slab, and framing sized for storage loads rather than habitable occupancy. On a 1950s wood-frame bungalow off Bristol Street in the central-westside flats, our crew opened a detached single-car garage that had served as a casita for years and found 60-amp service, cloth-wrapped wiring, and a slab that had never been waterproofed against the alley side. We pulled as-built drawings for the city’s Building & Safety Division, wrote the panel upgrade, cast-iron drain replacement, and Title 24 energy package in as line-item allowances, and priced the rotted sill plate and ember-resistant venting as a written change order the homeowner approved before we touched a stud.
Yes. Every project receives a written price before any work starts, per Haven Standard Clause 1. For Santa Ana’s older stock, we build in line-item allowances for the conditions we expect based on the age and type of structure. If we encounter something outside those allowances, we price it, document it with photos, and require your written approval before proceeding. No scope creep. No door-side upsells.
Santa Ana’s mild Mediterranean climate means cooling, not heating, drives mechanical design. We specify ductless mini-split systems sized for summer heat gain, which is significant on west- and south-facing detached units built close to block walls. The system, electrical circuit, and condenser pad are all included in our written price and documented in the permit set. Call (657) 567-6590 to discuss sizing for your specific orientation and lot conditions.
Yes. The namesake Santa Ana wind events each fall drive increasingly strict requirements for fire-resistant exterior finishes and ember-resistant venting, even in Santa Ana’s lower-risk flatland zones. We specify James Hardie fiber-cement siding or equivalent fire-resistant assemblies, and we detail vent screens that meet current wildfire-urban interface standards. These choices are written into your scope and priced from the start, not added when permits are already in review.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Santa Ana since 2015.