Junior ADU (JADU)

Junior ADUs

Carved out of the existing house, inside its current walls — usually the cheapest route to a second unit.

Junior ADU

How it compares to the other two.

Junior ADU

Carved out inside the existing house

Attached ADU

Shares at least one wall with the main house.

Detached ADU

A standalone structure in the yard.

Plans that fit

What this looks like on paper.

Every layout here is 500 sq ft or under — inside the statutory Junior ADU ceiling.
Gov. Code §66313

Home exterior & yard

Estate aerial view

Living room with fireplace

See the 7 plans at 500 sq ft or under

On site

Converting a garage into living space

35 sec A garage conversion in progress, and the retaining-wall engineering the sloped lot needed.

Rules that apply.

Limits vary by jurisdiction. These are the levers that decide what fits on your lot — we confirm every one of them against your city before design starts.

Maximum size500 sq ft of interior livable spaceGov. Code §66313
Must beContained entirely within the single-family residenceGov. Code §66313

All the rules that apply, with citations

Owner occupancyRequired only where sanitation is shared with the houseGov. Code §66333
No owner occupancyIf the unit has its own sanitation facilitiesGov. Code §66333

These are California state minimums — the floor every city has to allow. Your jurisdiction may permit more, and applies its own setbacks, height and design rules on top. We confirm all of it against your address before design starts. See regulations by city. Statutes reviewed 4 August 2026.

Is this you? When this is the right call

Feasibility → design → permit → build — the same four steps as every project we run. See how the process works.

Start with a free consultation.

Under an hour, no pressure — we talk through what your lot allows and give you a ballpark for your property. No charge, and no obligation to go further.