Junior ADU & Interior Conversion Cost - Design, Permits and Build Under One Contract

How Much Does Junior ADU & Interior Conversion Cost in Los Angeles?

A Junior ADU (JADU) and interior conversion in Los Angeles typically costs between $55,000 and $130,000 in 2026, depending on whether you’re converting a garage, carving a junior unit out of existing square footage, or doing both together. A straight garage-to-JADU conversion on an already-finished structure usually lands between $55,000 and $85,000. A full interior conversion with a kitchenette, bathroom, and separate entry commonly runs $85,000 to $130,000. These numbers reflect LA permit fees, local labor rates, and the realistic scope of work on the older housing stock you’ll find across the San Fernando Valley, South LA, and the Eastside.

We’re Lodgewick ADU Builders, the ADU company of the Kingswell family, and we’ve worked on Los Angeles lots long enough to know that ADU pricing here has almost nothing in common with pricing in a city three hours away. Before we go further: every Lodgewick project starts with a written price before a single nail is driven, backed by The Kingswell Guarantee. That number doesn’t change at the door.

Junior ADU & Interior Conversion Cost Breakdown (2026)

Here’s what Los Angeles homeowners are actually paying right now, line by line. These ranges assume a standard single-story home on a typical LA lot with reasonable access for materials and equipment.

What pushes a Los Angeles JADU toward the top of these ranges? Old electrical service that needs pulling entirely, a garage slab that’s cracked or below grade, plumbing that has to cross a foundation, or a lot in a Hillside or Coastal Overlay where the plan check takes longer and triggers extra review. What keeps you at the bottom? A detached garage with a solid slab, an existing subpanel that’s already correctly sized, and plumbing that can be routed to an existing cleanout within ten or twelve feet. We’ve seen a Highland Park garage conversion come in near $61,000 because the bones were good, and we’ve seen a comparable lot in Echo Park hit $104,000 because the garage had been sitting on a failing slab since the 1940s.

What Affects Junior ADU & Interior Conversion Pricing in Los Angeles

• Your existing structure’s condition. A garage that was framed properly and kept dry is a much cheaper JADU than one with rot, termite damage, or a slab that has shifted. We’ve opened up garages in Boyle Heights where the sill plate had been gone for a decade. That’s a real line item.
• How far plumbing has to travel. In Los Angeles, tying a new bathroom into the existing line is straightforward when the cleanout is close. When it isn’t, we’re cutting concrete in a finished floor or trenching across a yard. That swing alone can move a project $6,000 to $15,000.
• Electrical service capacity. Most LA homes built before 1970 have a 100-amp panel. A JADU with a kitchenette, mini-split, and bathroom fan usually needs an upgrade. DWP coordination and the panel swap itself typically add $3,500 to $9,000.
• Permit path and jurisdiction. The City of Los Angeles processes JADU permits through LADBS. A standard single-family lot is fairly predictable. Add a Hillside ordinance, an HPOZ (Historic Preservation Overlay Zone) in a neighborhood like Angelino Heights or Carthay Circle, or a Coastal Development Permit in Venice, and you’re adding months and money for design review and revisions.
• Fire separation and egress. A JADU tied to the main house has specific requirements for fire-rated assemblies and a code-compliant emergency escape window or door. Retrofitting existing walls to meet those standards is a line item homeowners don’t see coming, commonly $3,000 to $8,500.
• Materials and finish level. James Hardie siding, real tile, and solid-core doors cost more than builder-grade alternatives. We’ll quote you both so the difference is written down, not guessed at. If you’re looking at a prefab route with Abodu, Cover, Dvele, or Mighty Buildings alongside a JADU, that conversation changes the math, and we’re glad to walk through it.

If you want the deeper scope discussion – what’s included in a JADU versus a standard ADU, and where the line falls – our page on Junior ADU & Interior Conversion in Los Angeles covers it in detail.

How to Save on Junior ADU & Interior Conversion

Most of the savings in a Los Angeles JADU come from decisions made before the first permit is filed. A few that make a measurable difference:

1. Convert, don’t add. A JADU by definition lives inside the existing footprint or an existing structure. Every square foot you don’t add is a square foot you don’t frame, roof, or foundation. That’s why a garage conversion or interior conversion costs so much less per square foot than a ground-up ADU.
2. Keep plumbing on one wall. If you can cluster the kitchenette and bathroom against a single shared wall that already has a drain line, you can save thousands in rough-in. Bring us in early – before you’ve picked a layout in your head.
3. Reuse the garage’s existing slab and framing where code allows. We won’t cut corners on structure, but when a slab passes inspection and the framing is sound, there’s no reason to replace it.
4. Get the electrical panel right the first time. Homeowners sometimes try to avoid the upgrade and run into it later mid-project. Pricing it upfront with the rest of the scope keeps the number you were quoted the number you pay.
5. Bundle related work. If your main house needs a new roof or a service panel anyway, doing it during the JADU build usually costs less than doing it separately. That’s the kind of thing a written scope can capture.

Estimates with Lodgewick are free. Call (254) 602-5618 and we’ll put real numbers on paper for your lot, not a range you have to interpret.

Why LA Homeowners Choose Lodgewick for JADU Work

We started in 2010 as part of the Kingswell family of home-service companies, and the way we work comes down to what we call The Kingswell Way: say the price before the work, show up in the window we gave you, leave the place cleaner than we found it, put the guarantee in writing, and come back if it fails. Every Lodgewick project carries the 365-Day Done Right Promise. If something we built or installed isn’t right within that year, we come back and make it right – and that commitment is written on the project, not implied.

That matters for a JADU because these builds are usually occupied by family. A parent, an adult child, a caregiver. When a bathroom fan fails or a door won’t close right, you want a company that answers the phone. A live person answers ours 24 hours a day, seven days a week. Not a voicemail, not a chatbot.

We also work with the established names in ADUs and building materials – Abodu, Cover, Dvele, Mighty Buildings, Boxabl, Plant Prefab, Tuff Shed, and James Hardie – because matching the right system to the right lot is part of pricing it honestly. A prefab approach and a stick-built interior conversion aren’t the same conversation, and we don’t pretend they are.

One more thing worth naming: a lodge is a small house on a larger property. That’s exactly what a JADU is. The name isn’t marketing – it’s the whole idea.

FAQs – Junior ADU & Interior Conversion Cost

Can a JADU be cheaper than a full ADU in Los Angeles?

Yes, usually by a wide margin. A Los Angeles JADU commonly runs $55,000 to $130,000, while a detached ground-up ADU in the same city typically starts around $150,000 and climbs past $300,000 for larger units. The savings come from using existing walls, roof, and slab rather than building new. Call (254) 602-5618 for an exact quote on your lot – estimates are free.

Do I need a permit for a JADU in Los Angeles, and how much does it cost?

Yes. A JADU requires a building permit through LADBS, and permit, plan check, and school fees generally run $4,000 to $12,000 in Los Angeles. Unpermitted conversions can cost far more later when you try to sell or refinance. We handle the permit paperwork as part of the project. Call (254) 602-5618 and we’ll walk you through what your specific property needs.

How long does a garage-to-JADU conversion take in Los Angeles?

Most LA garage-to-JADU conversions take three to five months from permit issuance to final inspection, with plan check adding another six to twelve weeks depending on the jurisdiction. Projects in an HPOZ or with Hillside or Coastal overlays take longer. We give you a written arrival window and stick to it. Call (254) 602-5618 to schedule a free estimate.

Is it cheaper to repair or convert my existing garage?

Converting is almost always the better spend if the structure is sound. Repairing a failing garage without adding livable space leaves you with the same structure and no rental value or family housing. A conversion averages $55,000 to $85,000 in Los Angeles and produces a permitted, rentable or family-ready unit. If the garage is beyond saving, we’ll tell you that too. Call (254) 602-5618 for a straight answer.

What does a JADU add to my Los Angeles home value?

A permitted JADU adds real, financeable square footage, and in Los Angeles it can also add rental income that a lender will count. Appraisers generally value permitted ADU space at a meaningful premium over unpermitted space. The exact lift depends on your neighborhood, your lot, and your finishes, and we won’t quote you a number we can’t back up. Call (254) 602-5618 for a free estimate on the build side.

Getting Started

If you’ve been putting off a JADU because you don’t know what it actually costs, that’s the right instinct and the wrong reason to wait. We’ll put a real Los Angeles number on paper for your property, explain what’s driving it, and show you where the money goes. No price changes at the door, a written guarantee on the work, and background-checked, uniformed crews on your property. You’ll always know who’s on your lot and why.

Call Lodgewick ADU Builders at (254) 602-5618 for a free estimate. A live person answers, day or night. Whether you’re converting a garage in Reseda, carving out an interior JADU in Koreatown, or weighing a JADU against a larger build, we’ll give you the straight numbers and stand behind them in writing. Visit our home page to see how we work.

Pricing reflects the Los Angeles market as of 2026. Lodgewick ADU Builders offers free estimates – call (254) 602-5618.

Written by Russ Delmar, Owner at Lodgewick ADU Builders, serving Los Angeles since 2010.