ADU builders
ADU interior design: small-space choices that matter
By the HyreADU research desk. Last checked .
The short answer
ADU interior design is about making a small floor plan feel and work larger. The choices that matter most are fixed early: where the kitchen and bath go, ceiling height, windows and storage. Finishes such as paint, tile, flooring, cabinets and countertops are usually exempt from a permit under the model residential code.
Decide the fixed things first
Plumbing walls, window positions and ceiling height are set in the permit drawings and are costly to change later. Group the kitchen and bath on one wet wall. Put windows on two sides for light and cross air. Use full-height storage. See ADU design.
Finishes and permits
The International Residential Code lists painting, papering, tiling, carpeting, cabinets, countertops and similar finish work as exempt from a permit (R105.2). Local codes can amend that list. Anything that moves a wall, a fixture or a circuit goes back on the permit drawings.
Who to hire
Your designer can set the layout. An interior designer can help with finishes, lighting and furniture plans. Ask your builder how finishes are priced: named items or allowances. Small allowances are a common source of change orders. Put the finish list in the contract.
What to do next: read the questions to ask an ADU builder, check what decides ADU cost, then tell us about your project. Matching is not live yet, so we reply with information, not a quote.
Get ADU optionsQuestions
What finishes last in a rental ADU?
Durable, easy-to-clean surfaces. Choose for wear, not trend.
Does cabinet work need a permit?
Under the model code, no, unless plumbing or wiring changes. Check your local code.
How do I make an ADU feel bigger?
Fewer interior doors, more light, tall storage and a clear path through the room.
Does HyreADU design interiors?
No. HyreADU is a publisher.
Sources
- International Residential Code 2021, R105.2 (work exempt from permit). Checked October 27, 2026.
- California Building Standards Commission, current codes. Checked September 5, 2026.
HyreADU is a publisher. It does not design, permit or build ADUs, has no partner builders, and gives no legal, tax or engineering advice. Rules vary by state and city; California rules are labeled as such.