WHAT TO KNOW FIRST
A Junior Accessory Dwelling Unit is a distinct, smaller project category created within the walls of a proposed or existing single-family residence. It should not be treated as shorthand for every compact attached unit.
- Confirm the current JADU definition and property facts.
- Plan changes to the existing home and household circulation.
- Verify facility, sanitation, ownership, and occupancy questions from current sources.
Confirm that the proposed space fits the JADU category.
Current state and City materials should be checked for the applicable JADU definition, location within a single-family residence, maximum size, required cooking facilities, sanitation arrangement, and owner-occupancy provisions. The permit guide links the current Irvine application path.
A JADU differs from an attached ADU addition. Describing the intended facilities and the part of the home involved helps avoid planning around the wrong category.
Plan the project around everyday use of the main residence.
Review entries, privacy, sound, natural light, storage, shared or separate sanitation, cooking, heating and cooling, electrical loads, plumbing routes, and the effect on existing bedrooms, garages, and circulation. Record who will occupy the main home during construction and what temporary protection may be required.
Draw both households’ routes, not only the proposed unit. Show access to bathrooms, kitchens, laundry, mechanical equipment, outdoor space, meters and panels, and emergency exits. A compact plan can create daily conflicts when doors, storage, sound, or maintenance access are considered too late.
Make alterations and responsibilities explicit.
The scope should distinguish retained construction, demolition, new partitions, doors and windows, systems, finishes, permit work, inspections, and restoration. Use the Irvine ADU cost guide to compare complete proposals and the construction process to assign responsibilities.
Existing walls can conceal plumbing, wiring, framing, moisture damage, or earlier alterations. The proposal should say what is known, what investigation is included, how concealed conditions are documented, and who approves changes. Also identify which parts of the main residence must remain operational during the work.
Prepare a JADU conversation.
Call (949) 763-5237 with the property address, the area of the home being considered, and available records.
Confirm the facts before choosing a layout.
Use the estimate preparation checklist, or return to Irvine ADU Contractor for the full local service overview.
PRIMARY SOURCES
Agency references for the homeowner
Links checked September 7, 2026.
Use the official material above to prepare questions for the designer, contractor, or City reviewer.
NEXT FOR THE HOMEOWNER
Move from general guidance to project details.
BRING US THE PROPERTY DETAILS
Bring the house and yard into the conversation.
Call when you have the address and project type in mind. We can discuss the information worth gathering next.