Accessory dwelling unit companies — Madison, WI

Looking for accessory dwelling unit companies in Madison, WI? Call AccessoryDwellingUnit Pros for a contact a provider — no obligation. Licensed adu builders serve Madison and the surrounding area, and you'll get straight answers on timing and what affects the price.

Last updated: September 24, 2026

What affects the price

Building an ADU is a custom project, so costs vary based on your specific choices. Site conditions are the biggest factor; if your land requires significant grading, utility extensions, or foundation work, those expenses add up quickly. Choosing high-end finishes, custom cabinetry, or complex roof lines will also push the budget higher compared to a standard design. Prefabricated units often offer predictable costs, while custom site-built structures allow for more flexibility but can be harder to estimate upfront. Exact pricing confirmed free on the call.

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Frequently asked in Madison

What are the disadvantages of ADUs?

How much does an ADU cost in Wisconsin?

What are the rules for ADUs in Madison?

Is an ADU allowed in Madison?

Yes, accessory dwelling units are permitted in Madison, provided they comply with the city's zoning and building code requirements. These regulations typically cover aspects such as minimum lot size, occupancy limits, and design standards. Local professionals will ensure your project adheres to all these rules.

What is a typical ADU size for Madison?

Typical ADU sizes in Madison can range from compact studios around 300-400 square feet to larger units of 600-800 square feet, depending on your needs and lot. The professionals will help determine the optimal size based on your property and city ordinances. Call for a personalized assessment.

How long does it take to build an ADU in Madison?

The construction timeline for an ADU in Madison can vary, generally taking between 3 to 6 months, depending on permitting, the complexity of the design, and material availability. Early consultation with experienced builders can provide a more accurate projection for your specific project.

Also serving nearby: Rockford · Milwaukee · Kenosha · Elgin · Waukegan

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More on this: HUD ADU resources — ADU policy and financing research.

Service area details

280,305residents

3,373per sq mile

8ZIP codes served

Serving all of Madison — population 280,305; about 3,373 residents per square mile across 83.1 sq mi. ZIP codes covered include 53701, 53702, 53703, 53704, 53705, 53706, 53707, 53708.

Neighborhoods served in Madison: Nakoma, Shorewood Hills, Mendota Heights, Regent's Park, Old University District — and every surrounding area.