Want to turn an underused spare bedroom or a portion of your house into a legal second unit? A Junior ADU, or JADU, is often the most cost effective way to do it. Since you are working within your existing footprint—usually capping out at 500 square feet—you are not pouring a new foundation or framing exterior walls from scratch. But that does not mean you can just throw up some drywall and call it a day. Infinity ADU sees many JADU projects out on jobsites across Long Beach right now.
The Real Cost Ranges
Most JADU projects in our area land between $75,000 and $130,000 all-in. If you are converting an integrated space that already has a decent layout, basic flooring, and straightforward access, you might sneak in closer to the $75,000 mark. But if you are gutting an awkward room, adding an efficiency kitchen from scratch, upgrading your electrical panel, and carving out a brand-new exterior exit, you are looking at the higher end of that scale.
Square footage costs usually run from $180 to $320 per square foot. That sounds high compared to cosmetic interior remodeling, but remember that a JADU has to meet strict standalone building codes for efficiency kitchens, fire-rated separation assemblies from the primary house, and independent utility sub-metering or calculations.
What Actually Drives the Price Up
Every Long Beach property brings its own quirks to the table. Older homes in neighborhoods like Alamitos Heights or Bluff Heights often feature knob-and-tube wiring or vintage plumbing that will not pass modern code. When we open up the walls and find old galvanized pipes, the budget changes immediately.
- Electrical service: Jumping from a 100-amp panel to a 200-amp panel to handle a second kitchen load typically adds $3,500 to $6,000.
- Exterior egress: Cutting a brand-new doorway through stucco and framing out a secure exterior entrance requires structural headers and masonry work.
- Soundproofing and fire separation: State rules mandate a one-hour fire-rated wall and ceiling assembly between the main house and the JADU, plus sound insulation to keep tenants from hearing every footstep.
- Kitchen requirements: You do not need a full-size range, but California code demands an efficiency kitchen with a sink, a small refrigerator, and a built-in cooking appliance.
What Is Included in a Legitimate Quote
When Infinity ADU bids a JADU project, our numbers cover the entire lifecycle from blueprint to final sign-off. Be cautious of lowball bids that leave out important steps. A complete quote should explicitly itemize architectural drawings, structural calculations, city permit fees, plan-check turnaround times, rough framing, insulation, drywall, finish carpentry, flooring, lighting fixtures, and the complete efficiency kitchen setup. If a contractor hands you a flat two-sentence estimate, run the other way.
How to Avoid Overpaying
For homeowners in Long Beach, JADU construction requires working with local trades who know the Long Beach Development Services department and understand local inspection nuances. Make sure your contract includes a clear contingency fund of about 10% to 15% for unexpected field conditions behind the drywall. That way, when we open up a wall and find hidden termite damage or outdated wiring, you are not scrambling for cash to keep the project moving forward. Infinity ADU provides JADU construction services for homes in Long Beach, California.