Basement ADU and Junior ADU Conversion

Basement ADU

A basement ADU converts below-grade space into an independent dwelling with its own entrance, kitchen, and bathroom. Because the shell already exists, the main work is egress, ceiling height, moisture control, insulation, and adding the kitchen and bathroom. A separate, code compliant exit is usually the most important feasibility question.

Junior ADU (JADU)

A junior ADU is a smaller unit created within the existing footprint of the house, typically with a more limited kitchen. JADUs are generally the smallest and least expensive ADU type, though the exact rules, including any size cap, depend on your jurisdiction.

What to consider

• Egress: a basement unit needs a compliant second exit, which can require a new window well or door.
• Ceiling height and moisture, which are common limiting factors below grade.
• Sound separation and a clear division between the unit and the main home.
• Whether your jurisdiction recognizes junior ADUs and what size and kitchen rules apply.

What the matched builder handles

We connect you with a licensed local builder who serves your jurisdiction. The builder assesses the space, designs the conversion, handles permitting, and performs the work. We are a matching and marketing service, not a contractor.