Trusted Garage Conversion ADU for Pasadena Homeowners
A garage conversion ADU in Pasadena typically runs $95,000-$185,000 all-in, from measured drawings through final inspection, and most projects reach certificate of occupancy within 8-14 months. Since 2015, Ellery ADU Studio has designed, permitted, and built over 900 ADUs across Southern California, every one with a written price before any work started and a documented photo record when work was complete. We’re a design-build studio, not a contractor who outsources drawings - the permit set, the construction, and the warranty live under one contract at one written price, so neither the designer nor the builder can point at the other when something is off. If you’re weighing a garage conversion against a new detached unit or wondering whether your 1920s garage slab will pass structural review, call us at (626) 427-9813. A live person answers 24/7, and we offer a Free Second Opinion on any written estimate already in your hands.
What Our Garage Conversion ADU Service Includes
Attached Garage Conversion
An attached garage conversion turns the structure already sharing a wall with your main house into a self-contained dwelling unit with its own kitchen, bathroom, and sleeping area. In Pasadena, these conversions often trigger fire-separation requirements between the ADU and the primary residence - typically one-hour rated assemblies - and the existing slab depth determines whether you need a new foundation or can work with what’s there. At Ellery ADU Studio, we start with a structural assessment of your garage’s existing framing, slab, and roof load path; we then produce the full permit set in-house, coordinate with Pasadena Building & Safety on any R-3 occupancy questions, and build to that same set under our single contract. The Haven Standard, Clause 1, locks your written price before any work begins.
Detached Garage Conversion
A detached garage conversion creates a standalone dwelling unit separate from your main house, which in Pasadena means navigating setback requirements, utility trenching, and often a more complex electrical service upgrade. These projects frequently involve extending water, sewer, and gas lines from the main residence across the yard, and the city’s hillside zoning overlays in areas like Linda Vista and San Rafael can trigger additional geotechnical review. We handle the full utility coordination - including the PG&E service upgrade, the sewer lateral inspection with Pasadena Public Works, and the water meter split if required - all within the same contract that covers your architectural drawings and construction. Our documented photo record on every visit means you see the trenching, the rough plumbing, and the insulation before anything gets covered.
Carport Conversion
A carport conversion starts with less structure than a garage - typically open sides, a lighter roof, and no existing slab rated for habitation - which means more new construction and a different permit path in Pasadena. These projects almost always require a new foundation, full envelope walls, and new electrical service from the ground up, though they can still qualify under California’s streamlined ADU laws if the carport was legally permitted when built. We assess whether your carport was originally permitted (Pasadena’s records go back to the 1940s in many neighborhoods), then design the new structure to match or complement your existing architecture while meeting current energy code - Title 24, Part 6 - with the HVAC and insulation package specified from day one. Your written price includes the full structural, MEP, and energy compliance documentation.
Garage Partition & Bathroom Add
A garage partition and bathroom add creates a Junior ADU (JADU) or a partial conversion within the existing garage footprint, often leaving storage or parking space intact while adding a kitchenette and full bath to one portion. In Pasadena, JADUs are limited to 500 square feet and must include an efficiency kitchen, which means careful space planning around existing door locations, ceiling heights, and the path of existing utilities. We model multiple partition layouts in our permit set - showing exactly where the wet wall goes, how the Sanitary T ties into your existing sewer line, and where the mini-split condenser sits - so you can compare configurations before signing. The Haven Standard, Clause 5 (No Surprises), locks the scope at signing; no door-side upsells, no scope creep.
Garage JADU
A garage JADU, or Junior Accessory Dwelling Unit, is the most compact conversion option - up to 500 square feet within your existing garage, with an exterior door, a small kitchen with cooking appliances, and either a new bathroom or shared access to the main house’s facilities. Pasadena requires JADUs to be created within the walls of the proposed or existing single-family residence or accessory structure, which means your garage must be legally permitted and the owner must occupy either the main house or the JADU. We verify your garage’s permit history with the city, confirm owner-occupancy compliance, and produce a JADU-specific permit set that addresses Pasadena’s tighter fire-sprinkler triggers and the reduced parking replacement requirements under state law. Every JADU we build carries the same 365-Day Done Right Promise as our full ADUs.
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.
Brands We Specify and Coordinate for Garage Conversion ADU
Ellery ADU Studio specifies and coordinates prefab and modular systems within the same single contract that covers your site-built conversion, which matters when you’re comparing a traditional stick-frame garage conversion against a panelized or modular alternative. We’ve worked extensively with James Hardie fiber-cement siding systems on Pasadena garage conversions where the existing structure needs new exterior cladding to match the main house - we specify the HardiePanel vertical boards for modern elevations and the HardiePlank lap siding for Craftsman restorations in Bungalow Heaven, with the full moisture-management detail drawn into the permit set. For homeowners considering a modular addition alongside their garage conversion, we coordinate Abodu units on the same property - handling the site prep, utility tie-ins, and the coordination between the stick-built garage ADU and the prefab unit under one contract, one written price, one point of accountability.
We also specify Cover and Dvele systems for clients who want a high-performance, panelized approach to the garage conversion itself - particularly in Pasadena’s hillside districts where factory-built panels reduce on-site construction time and weather exposure. Whether your project is fully site-built, hybrid, or incorporates a prefab component, the permit set is the core product, not an afterthought, and every specification is backed by The Haven Standard in writing. If you have a written estimate from another firm for any of these systems, we’ll provide a Free Second Opinion.
Signs You Need Garage Conversion ADU Right Now
- Your garage sits unused while housing costs in Pasadena keep climbing. The median rent for a one-bedroom in Pasadena now exceeds $2,500, and a converted garage ADU can generate $24,000-$36,000 in annual rental income while adding $150,000-$250,000 to your property’s assessed value. The longer the garage sits empty, the longer you’re carrying that opportunity cost.
- Your adult child or aging parent needs independent housing nearby. Multi-generational living is the fastest-growing household type in Los Angeles County, and Pasadena’s tight rental market makes off-site options expensive or unavailable. A garage ADU keeps family on the property with privacy for everyone, and California’s ADU laws prohibit owner-occupancy requirements for standard ADUs - though JADUs still require it.
- You received a notice from Pasadena Code Enforcement about unpermitted garage habitation. Converting a garage to living space without permits creates liability exposure, invalidates your homeowner’s insurance for that space, and can trigger fines of $100-$500 per day under Pasadena Municipal Code. A permitted conversion protects your investment and your coverage.
- Your garage slab is cracking, the roof leaks, or the framing shows moisture damage. These are not just maintenance issues - they’re structural conditions that will get more expensive and may disqualify the garage from conversion if they progress. Our structural assessment determines whether the existing slab, walls, and roof can support a conditioned dwelling or whether targeted repairs need to be built into the permit set.
- You’re holding a written estimate from another firm that feels vague or incomplete. Estimates that lack line-item foundation work, utility trenching, or permit fees often balloon by 30-50% once construction starts. Under Haven Standard Clause 1, our written price includes every line item from drawings through final inspection - and we’ll review any competitor’s written estimate for free.
Our Garage Conversion ADU Process - Step by Step
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Site Assessment & Feasibility Study. We measure your garage, photograph the existing conditions, and verify permit history with Pasadena Building & Safety. We test the slab for thickness and reinforcement, assess the roof structure for live-load capacity, and identify utility access points. You receive a documented photo record of everything we found, not a summary of how it felt - along with a written feasibility report stating whether your garage qualifies for streamlined permitting or requires additional review.
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Design & Permit Set Production. Our in-house designers produce the full architectural, structural, MEP, and energy compliance documentation - the same permit set we build from, not a separate package for a contractor to reinterpret. For Pasadena, this includes compliance with the city’s Historic Preservation guidelines if you’re in a landmark district, the hillside grading ordinance for properties above the 800-foot contour, and the specific fire-separation details for attached conversions. You review and approve every sheet before submittal.
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Permit Submission & City Coordination. We submit to Pasadena Building & Safety, respond to plan-check comments, and coordinate any required pre-construction meetings. Our familiarity with Pasadena’s ADU checklist - updated in 2023 to align with SB 9 and SB 10 - means we typically clear plan check in 6-10 weeks for standard conversions, compared to 4-6 months for first-time filers. We handle all revisions and resubmittals at no additional cost.
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Construction & Weekly Documentation. Our background-checked, uniformed crews build to the permitted drawings, with a documented photo record on every visit. You see the foundation repair, the rough plumbing pressure test, the electrical panel upgrade, and the insulation before drywall - every phase, with timestamps. The Haven Standard, Clause 5, locks the scope at signing, so the price you approved is the price you pay.
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Final Inspection & 365-Day Done Right Promise. We coordinate all inspections - building, electrical, plumbing, mechanical - and do not request final payment until Pasadena issues the certificate of occupancy. Then the 365-Day Done Right Promise takes effect: if the finished ADU is not built to the permitted drawings, Ellery makes it right, in writing, before the project starts. This is not a verbal assurance; it’s Haven Standard Clause 8, included in every contract.
How Much Does Garage Conversion ADU Cost in Pasadena?
A typical attached garage conversion in Pasadena runs $95,000-$140,000 all-in, from measured drawings through final inspection - see our Garage Conversion ADU cost guide for full pricing breakdowns. A detached garage conversion, with the additional utility trenching and electrical service upgrade, typically runs $125,000-$185,000. Carport conversions start higher - $110,000-$165,000 - because you’re building walls and a foundation where none existed. Garage JADUs and partition conversions, being smaller and often sharing utilities, typically fall in the $75,000-$115,000 range.
| Project Type | Typical Range in Pasadena | Primary Cost Drivers |
|---|---|---|
| Attached Garage Conversion | $95,000 - $140,000 | Slab condition, fire separation, kitchen/bath finish level |
| Detached Garage Conversion | $125,000 - $185,000 | Utility trenching length, PG&E upgrade, hillside access |
| Carport Conversion | $110,000 - $165,000 | New foundation, full envelope, new electrical service |
| Garage JADU / Partition | $75,000 - $115,000 | Wet wall location, mini-split vs. central HVAC, finish level |
What moves you within these ranges? Foundation work is the biggest variable - a 4-inch unreinforced slab from the 1950s typically needs replacement, adding $15,000-$30,000, while a 1980s 6-inch slab with rebar may need only perimeter drainage. Utility distance matters: trenching sewer 40 feet across a flat yard is straightforward; 80 feet up a Linda Vista hillside with retaining walls is not. Finish selections - tile versus vinyl, quartz versus laminate, Bosch versus Frigidaire - move the needle $10,000-$25,000. Under Haven Standard Clause 1, every project is quoted with a written price before any work begins. The words “call for a quote” do not appear on this site because they do not appear in our practice.
To avoid overpaying, get at least two written estimates with line-item breakdowns, and compare what’s actually included - permit fees, utility connections, and finish allowances are the most common omissions that lead to change orders. Our free estimate includes all three, with the allowance specified in dollars, not vague language. If you have a written estimate in hand, we’ll provide a Free Second Opinion.
Garage Conversion ADU Near Pasadena - Our Service Area
Ellery ADU Studio works throughout the San Gabriel Valley and northeastern Los Angeles County, with garage conversion ADU projects completed in Alhambra, Glendale, Arcadia, Temple City, Rosemead, Monterey Park, El Monte, East Los Angeles, Los Feliz, Burbank, and North Hollywood. Typical initial site assessment scheduling is within one week for Pasadena addresses and 10-14 days for outlying cities. We know the specific requirements of each jurisdiction - Glendale’s design review for hillside properties, Alhambra’s parking replacement calculations, Burbank’s utility coordination timelines - and we produce jurisdiction-specific permit sets rather than recycling Pasadena drawings with a new title block. Whether you’re in Bungalow Heaven, Annandale, or the Chapman Woods area, the process and the written price guarantee remain identical.
Serving Pasadena, CA - Our Local Coverage Area
We’re based in the Pasadena area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
Frequently Asked Questions - Garage Conversion ADU in Pasadena
A garage conversion ADU transforms an existing garage - attached, detached, or carport - into a legally permitted dwelling unit with independent living facilities. In Pasadena, this means meeting California’s ADU laws, Pasadena’s municipal code, and the California Building Code for residential occupancy, including requirements for sleeping area, kitchen, bathroom, and independent exterior access. Ellery ADU Studio handles the full conversion under one contract: feasibility study, permit set, construction, and final inspection, with a written price before any work begins per Haven Standard Clause 1.
Most garage conversion ADUs in Pasadena reach certificate of occupancy within 8-14 months from contract signing, with design and permitting typically consuming 3-5 months and construction 5-9 months depending on scope and seasonal conditions. Detached conversions with utility trenching and hillside properties tend toward the longer end; attached JADUs with simple slab conditions often finish faster. We provide a written schedule with your estimate, updated weekly during construction, and we do not promise timelines we cannot document in the permit path. Call (626) 427-9813 to discuss your specific garage and timeline.
Garage conversion ADUs in Pasadena typically range from $75,000 for a compact JADU to $185,000 for a detached conversion with full utility work, with most attached conversions falling between $95,000 and $140,000. The final cost depends on slab condition, utility distance, finish selections, and whether hillside or historic district requirements apply. Under Haven Standard Clause 1, every project receives a written, line-item price before any work begins - no “call for a quote,” no range that shifts later. Call (626) 427-9813 for your specific written estimate; the consultation is free.
Yes - we specify and coordinate Abodu, Cover, Dvele, and other prefab or panelized systems within the same single contract that covers your garage conversion. This matters when you’re adding a modular unit elsewhere on the property or when a panelized approach reduces construction time for the garage conversion itself, particularly in Pasadena’s hillside zones. Our permit set coordinates the interface between prefab and site-built components, and your written price covers both. If you have a prefab quote in hand, we’ll provide a Free Second Opinion on how it compares to our integrated approach.
We do not offer “emergency” construction for planned ADU work - garage conversions are six-figure projects requiring design, permitting, and phased construction, not same-day dispatch. We do expedite the permitting phase where possible: our pre-submittal conference with Pasadena Building & Safety often catches plan-check issues before formal submission, and our familiarity with the city’s ADU checklist reduces revision cycles. For code enforcement situations where unpermitted garage habitation must be addressed quickly, we prioritize the feasibility study and permit set production to get you legal as fast as the city allows. Call (626) 427-9813 to discuss urgency and realistic timelines.
Every garage conversion ADU carries our 365-Day Done Right Promise: if the finished unit is not built to the permitted drawings, Ellery makes it right, in writing, before the project starts. This is Haven Standard Clause 8, not a verbal afterthought. Beyond the 365-day period, California law requires a 10-year structural warranty on new construction, and we honor all manufacturer warranties on fixtures, appliances, and HVAC equipment installed in your conversion. The documented photo record from every visit serves as the baseline for any warranty claim - you and we both know exactly what was done.
Clear your garage of vehicles and storage items so we can photograph and measure the full interior, locate your property survey or plot plan if you have it, and gather any existing permits or inspection records for the garage structure. If you have a written estimate from another firm, bring it - we offer a Free Second Opinion on any written estimate in hand. We’ll handle the rest: permit history lookup with Pasadena, utility mapping, and the structural assessment. The consultation takes 60-90 minutes, and you’ll receive a documented photo record and written feasibility report within 48 hours. Call (626) 427-9813 to schedule.
Schedule Your Garage Conversion ADU Service in Pasadena Today
Call (626) 427-9813 to schedule your free estimate. A live person answers 24/7 - no voicemail queue, no callback promise that doesn’t materialize. Nadia Ellery and the team at Ellery ADU Studio will assess your garage, verify permit history with Pasadena Building & Safety, and deliver a written, line-item price before any work begins, backed by The Haven Standard. If you already have a written estimate from another firm, we’ll provide a Free Second Opinion. Your garage is already on your property. The only question is whether it will keep storing boxes or start generating income, housing family, or building equity - with a permit set and warranty that protect you either way.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Pasadena since 2015.