A small modern backyard cottage with board-and-batten siding, a covered porch and a gravel path lit by string lights at dusk

Accessory dwelling units (ADUs)

A small, separate home on the same lot, built to code with its own kitchen and bath.

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What this covers

An accessory dwelling unit is a complete small home on the same lot as the main house: a backyard cottage, a converted garage, or a basement unit with its own entrance. The work covers the local rules and permits, design, utility connections, foundation and construction, and every system a home needs, ending with the inspection that lets it be occupied.

When to call

  • A parent, adult child or caregiver who needs a place of their own nearby.
  • A lot and local rules that allow a second unit.
  • An existing garage or basement that could become a unit.

What to expect

  1. Rules and designThe company confirms what the city allows for size, setbacks and parking, then designs to it.
  2. Utilities and foundationWater, sewer and electrical connections are planned and the foundation built.
  3. ConstructionFraming, roof, exterior, systems, insulation and finishes, with inspections at each stage.
  4. OccupancyFinal inspection and certificate of occupancy, then a walk-through.

Get a certified company

Look up a certified company by ZIP code. Every company's license, insurance and trades are verified before it is listed, and placement is never paid.

Find a certified company

Text 844-7-RESTORECall 844-7-RESTORE

Questions people ask

Is an ADU allowed where I live?

Rules vary by city and state and have loosened in many places. The company checks the local ordinance before any design work.

Does it need its own utilities?

Usually it connects to the main house's water, sewer and electrical with its own shutoffs and sometimes its own meter. The design step settles this.

Can an ADU be rented?

Many cities allow it with conditions. That is a question for your city and, if you have one, your homeowners association.

Related: Garage conversion · Basement finishing · Room additions · All remodeling

This page describes what the service involves. The company you hire sets the scope, the schedule and the price, and your contract is with that company. We verify credentials and collect reviews from real jobs. We do not guarantee any company's workmanship. Safety steps are general guidance. When in doubt, leave the home and call 911.