Junior ADU · Los Angeles
That spare bedroom or attached garage could be a permitted Junior ADU. It's the fastest, lowest-cost way to add an independent, rent-ready unit inside the LA home you already own.
What Is a JADU
A Junior ADU (JADU) is a small independent living space, up to 500 square feet, created inside the existing footprint of your single-family home, usually a converted bedroom, den, or attached garage. The walls, roof, and foundation are already there, and you're not paying to build them twice. That makes a JADU typically the cheapest and quickest path to a rentable or family unit in Los Angeles.
As a licensed Los Angeles ADU contractor (CSLB #1045030), Athenian Builders Group handles the whole conversion: design, permitting, and construction, with one accountable team, a fixed price in writing, and a 2-year workmanship warranty.
The Rules
Both California and the City of Los Angeles spell out what makes a legal JADU. Your space has to check every box on this list:
Rules summarized for general guidance and can change; we confirm current local and state requirements for your specific property during the free walkthrough.
JADU vs. Full ADU
Up to 500 sq ft, built inside your existing home. It costs the least and permits the fastest, and you'll need to live on the property. A good fit for an in-law suite, an office that can earn rent later, or a first rental.
Up to 1,200 sq ft and fully separate, with its own kitchen, bath, and entrance. It costs more, and it returns more in rent and resale value. The right call when you have the backyard and want a true second home.
Not sure which one your lot allows? That's the first question we answer at the free on-site feasibility visit. See our full ADU construction services for detached and attached builds.
Transparent Pricing
With a JADU you're not paying for a new foundation, roof, or utility lines, which is why it's usually the least expensive ADU. Here is how it compares to other ADU types in 2026:
| ADU Type | Typical Size | Typical Cost (2026) |
|---|---|---|
| Junior ADU (JADU) | up to 500 sq ft | $90k – $160k |
| Garage Conversion | 300–500 sq ft | $100k – $180k |
| Attached ADU | 400–800 sq ft | $180k – $320k |
| Detached New-Build | 500–1,200 sq ft | $250k – $450k |
Typical Los Angeles ranges for 2026, not quotes. Final cost depends on the existing space, plumbing runs, and finishes. Financing is available for qualified homeowners. See remodel financing options.
Estimated project cost
Why Athenian
Most "ADU builders" in LA are design shops or brokers who sub the actual construction out. We are a single self-performing team: we design it, pull your JADU permits through LADBS or your city's building department, and build it with our own crews. That means one point of contact, a fixed itemized price before we start, a firm timeline in writing, and a written 2-year workmanship warranty on everything we build.
Questions
A JADU borrows your home's existing walls, foundation, and utility connections, so it typically runs $90k–$160k. A detached new-build commonly runs $250k–$450k. The exact savings come down to how much plumbing and electrical the space needs.
Yes, as a long-term rental. One catch: California requires the owner to live in either the main house or the JADU, so renting both units as short-term vacation stays is restricted. We walk you through exactly what your property allows during the free walkthrough.
No. State law exempts JADUs from added off-street parking, and that's one reason they permit faster and cost less than a standalone ADU.
The structure is already standing, so a JADU conversion is one of our quicker projects: commonly a few months from permit to finish, depending on scope and city review times. You get a firm timeline in writing before we start.
Yes. We draw the plans, pull your JADU permits, and manage every inspection ourselves. Approvals stay on our plate, not yours.
Start with a free on-site feasibility visit. You approve a fixed, itemized price for your Los Angeles JADU before we open a single wall. We serve LA and all of LA County. Call (310) 857-2520.
Takes about a minute. We reply the same business day and set up a free on-site visit.
