Trusted Junior ADU & Interior Conversion for Los Angeles Homeowners
A Junior ADU (JADU) is a self-contained living unit carved out of the existing footprint of your single-family home, with its own entrance, kitchen, and bathroom. In Los Angeles, most interior conversions run between $95,000 and $190,000 all-in, from drawings through final inspection, and the permit process typically takes four to eight months depending on your neighborhood’s specific zoning overlays. Ellery ADU Studio has designed, permitted, and built 900+ ADUs since 2015, every one with a written price before work started. We manage our Junior ADU & Interior Conversion in Los Angeles as one contract: the drawings, the permit set, and the construction are ours, so there’s no designer-versus-builder gap when something needs attention. Call (971) 497-2402 to talk through your property’s specific constraints. A live person answers.
What Our Junior ADU & Interior Conversion Service Includes
Basement ADU
A basement ADU takes existing below-grade square footage and turns it into a legal dwelling unit. Los Angeles basements are less common than in other markets, which means when one exists, the conversion math often works in your favor: the structural shell, waterproofing, and egress decisions are the entire project. We assess ceiling height (minimum 7 feet under California building code), moisture intrusion history, and access for a separate entrance. Our permit set documents exactly what gets altered, and our written quote locks the scope before any structural work begins.
Above-Garage ADU
An above-garage ADU converts the unfinished space over a detached or attached garage into a rentable unit. The two big questions are always structural: whether the existing garage foundation can carry the added live load, and whether the garage ceiling framing can support a floor system. In Los Angeles neighborhoods like Silver Lake and Eagle Rock, we regularly see 2×6 ceiling joists that need reinforcement to carry a dwelling unit. We spec the reinforcement, the stair access, and the insulation package in the permit set, and the price is written before the first hammer swing.
Room-to-ADU Conversion
A room-to-ADU conversion repurposes existing bedrooms, dens, or bonus rooms into a self-contained unit with its own kitchenette and bath. This is the most common Junior ADU & Interior Conversion - Bell path in Los Angeles because the building envelope already exists and the city’s JADU ordinance allows up to 500 square feet without additional parking requirements. We document what stays, what gets demolished, and where the new utility runs go. The plumbing and electrical scope is where costs move, and we show you those line items in the written quote before you commit.
Attached Addition ADU
An attached addition ADU extends your home’s footprint while sharing one wall with the main structure. This is the right move when you have a side yard or rear yard that can absorb 300 to 800 square feet of new construction. Los Angeles setback variances, meaning the extra distance the city requires between your new walls and the property line, often determine whether the addition is feasible and how large it can be. We handle the variance paperwork, the structural tie-in details, and the fire separation requirements in a single permit set with a single written price.
Interior JADU
A Junior ADU & Interior Conversion - Huntington Park style interior JADU is the most compact and cost-effective ADU type: a conversion of existing interior space, typically 150 to 500 square feet, with efficiency kitchen and its own exterior entrance. California state law requires no additional parking and no added square footage for JADUs, which makes this the fastest path to a legal rental unit in Los Angeles. We walk the property, identify which interior walls can move, and where the new entrance makes sense for both privacy and code compliance. The permit set covers every change, and the 365-Day Done Right Promise means if it’s not built to those drawings, we make it right, in writing.
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 Service for Junior ADU & Interior Conversion
When an interior conversion calls for prefabricated components, we specify and coordinate systems from James Hardie, Abodu, and Cover within the same contract. For siding and exterior finishes on attached additions, we use James Hardie fiber cement almost exclusively in Los Angeles: it holds up to the marine layer moisture in Venice and the dry heat in the Valley without the expansion cracks we see in wood siding. The product is documented in the permit set, so the building inspector knows exactly what they’re looking at.
For clients who want to shortcut framing time, Abodu and Cover both manufacture modular units that can be crane-set onto a prepared foundation. We’ve coordinated these systems for clients across Los Angeles, managing the site prep, utility hookups, and final finish work under our single written contract. Whether your project uses Abodu, Cover, Dvele, or none of the above, the same rule applies: one written price, one contract, one accountable team.
Signs You Need Junior ADU & Interior Conversion Right Now
- Your mortgage math has shifted. If you bought between 2015 and 2025, your monthly payment is likely substantial. An interior conversion creates rental income from square footage you already own, without the cost of new foundation or roof work.
- You have unused rooms that cost you money every month. A den that sits empty still gets heated, cooled, and taxed. Converting it to a legal JADU turns dead square footage into a documented asset with its own address.
- Multigenerational family needs are pressing. Aging parents or adult children moving back home need privacy and independence. A JADU with its own entrance and kitchenette keeps family close without sharing one kitchen and one bathroom.
- You’re planning a bigger ADU later. A JADU is often the first phase of a larger ADU strategy. We design the JADU with future expansion in mind, so the plumbing stub-outs and electrical panel capacity are already sized for the next phase.
- Your property tax basis is locked low. Adding square footage triggers reassessment on the new area only, not the entire property, under California Proposition 13. Interior conversions preserve your existing basis while adding rentable value.
Our Junior ADU & Interior Conversion Process - Step by Step
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Site assessment and feasibility review. We walk the property in Los Angeles, measure existing spaces, and check the zoning overlays for your specific neighborhood, from the coastal zone rules in Pacific Palisades to the Hillside Ordinance constraints in Mount Washington. You receive a written feasibility summary that identifies what’s possible, what’s marginal, and what’s off the table.
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Preliminary design and written price. We develop floor plan options and a written scope of work with a fixed price. Under Haven Standard Clause 1, this price is documented before any work begins. No allowances, no open-ended line items, no “we’ll see what we find.”
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Permit set production. Our design team produces the full permit set: site plan, floor plans, structural drawings, Title 24 energy calculations, and electrical and plumbing sheets. The permit set is the core product, not an afterthought. Every wall, every outlet, every structural connection is drawn and specified.
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Permitting and city coordination. We submit to the Los Angeles Department of Building and Safety and manage the plan check comments until the permit is issued. We handle correction cycles, resubmittals, and the inevitable questions from plan check engineers. You don’t chase the city; we do.
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Construction and documented completion. Our crews build to the permitted drawings, with a documented photo record on every visit. You receive evidence of what was found and what was done, not a summary of how it felt. At final inspection, we walk the finished unit with you and confirm it matches the drawings you approved.
How Much Does Junior ADU & Interior Conversion Cost in Los Angeles?
A typical Los Angeles interior JADU conversion runs $95,000 to $150,000 depending on kitchen scope, bathroom finish level, and whether you need a new exterior entrance or can repurpose an existing door. Attached addition ADUs run higher, typically $180,000 to $320,000, because they involve new foundation, framing, and roof structure. Basement ADUs range from $130,000 to $210,000 depending on waterproofing requirements and ceiling height remediation. Above-garage units typically land between $150,000 and $240,000 because of the structural reinforcement and stair access costs. These are real numbers from our project history in Los Angeles, and every one of them was given to the client in writing before the project started.
What moves the price is rarely the square footage; it’s the unseen conditions: sewer line depth, electrical panel capacity, and the structural condition of whatever you’re converting. We find these things before we quote, not after. And under the Haven Standard, our written price is a fixed price. No door-side upsells, no scope creep, no change orders you didn’t authorize in advance. Call (971) 497-2402 for a written quote on your specific property. You’ll get exact numbers, not a range.
Junior ADU & Interior Conversion Near Los Angeles - Our Service Area
We serve Los Angeles County from the San Fernando Valley through the Westside, South Bay, and Northeast LA, including Sherman Oaks, Culver City, Torrance, Highland Park, and Pasadena. A site assessment is scheduled within five business days in most cases. The home page has details on how we work, and our Junior ADU & Interior Conversion in Los Angeles page covers the LA process in depth. We also run parallel operations for Junior ADU & Interior Conversion in Houston and Junior ADU & Interior Conversion in San Antonio. Wherever the property sits, the written price rule applies.
Serving Los Angeles, CA - Our Local Coverage Area
We’re based in the Los Angeles 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 - Junior ADU & Interior Conversion in Los Angeles
A Junior ADU is a self-contained living unit of up to 500 square feet created entirely within the existing walls of a single-family home, with its own entrance, small kitchen, and bathroom. Junior ADU & Interior Conversion in South Gate falls under interior conversion, the broader category that includes JADUs, basement units, above-garage units, and attached additions. California law makes JADUs the easiest ADU type to permit, with no additional parking required and no added square footage. Ellery ADU Studio handles every step from feasibility through final inspection under one written contract.
Most interior JADU conversions in Los Angeles take four to eight months from initial drawings to final inspection. The permitting phase with the Los Angeles Department of Building and Safety is the biggest variable, typically running eight to sixteen weeks depending on plan check workload and correction cycles. Construction for an interior conversion usually takes eight to twelve weeks if the existing structure is sound. Call (971) 497-2402 and we’ll give you a realistic timeline for your specific property based on current city processing times.
A typical interior JADU in Los Angeles runs $95,000 to $150,000 all-in, from drawings through final inspection. The price depends on kitchen scope, bathroom finish level, and whether the existing structure can support the conversion without major structural work. Every quote from Ellery ADU Studio is a fixed, written price given before any work starts, per Haven Standard Clause 1. Call (971) 497-2402 for exact numbers on your property, not a range.
Yes, we specify and coordinate Abodu, Cover, and James Hardie systems within our design-build contracts. When a client wants a factory-built unit, we handle the site prep, foundation, utility connections, and finishes under the same fixed written price. The prefab unit is the variable, not our scope. We’ll walk you through whether a factory-built approach makes sense for your Los Angeles lot or whether a site-built conversion is more cost-effective.
Yes, we produce the full permit set and manage the submission, plan check, and correction process with the Los Angeles Department of Building and Safety. The permit set is the core product at Ellery ADU Studio, not an afterthought, and includes site plans, structural drawings, Title 24 calculations, and electrical and plumbing sheets. We handle correction cycles until the permit is issued. You never chase the city; we do.
Every project is covered by the 365-Day Done Right Promise, which states in writing that if the finished ADU is not built to the permitted drawings, we make it right. The promise is documented before the project starts, not referenced after something goes wrong. We also provide a documented photo record on every visit, so there’s a clear record of what was installed and when. Call (971) 497-2402 to see a sample warranty document.
Have your property address ready and any existing floor plans or survey documents you may have from your purchase. We’ll handle the rest: we pull the city records, check the zoning overlays, and measure the existing spaces. You don’t need to clean, clear, or prep anything before we arrive. The assessment is free, and you’ll receive a written feasibility summary within a few days of the visit.
Schedule Your Junior ADU & Interior Conversion Service in Los Angeles Today
A Junior ADU is a documented asset, not a weekend project. Get a written price before any work starts, a permit set that the city approves, and a 365-Day Done Right Promise in writing. Call (971) 497-2402 to schedule your free site assessment. A live person answers, and the estimate doesn’t cost you a dime.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Los Angeles since 2015.