Accessory dwelling unit cost — Madison, WI
Last updated: September 24, 2026
What affects the price
Building an ADU is a major project, and the final bill depends on a few key things. Site prep is a big factor; if your land is sloped or needs extensive utility connections, costs go up. The materials you choose—from siding to kitchen finishes—also change the math significantly. Whether you’re building a detached unit or converting an existing garage shifts the permit requirements and structural work needed. We provide exact pricing confirmed free on the call.
About this service
The investment required for an ADU depends on your site conditions, the complexity of the design, and the materials selected for the interior. Larger units with custom features naturally shift the price higher compared to standard, compact models. Exact pricing confirmed free on the call.
Frequently asked in Madison
What does 'accessory dwelling unit' mean for Madison residents?
For Madison residents, an accessory dwelling unit (ADU) means adding a secondary, independent living space on their property. This can be a detached unit like a backyard cottage or an attached unit such as a basement apartment. It's designed to be a complete living quarters.
What are the costs involved in building an ADU in Madison?
What are the benefits of an affordable ADU?
An affordable ADU provides a cost-effective way to increase housing options or rental income. While there's an initial investment, the long-term benefits of added property value and potential revenue can make it financially sound. Discuss your budget when you call for a quote.
Who are the best ADU builders in Madison?
What are the requirements for building an ADU in Madison?
What is a prefabricated accessory dwelling unit?
A prefabricated accessory dwelling unit is a unit that is built off-site in a factory and then transported to your location in Madison for installation. This method can sometimes speed up construction time. Discuss prefabricated options when you call for your estimate.
Also serving nearby: Rockford · Milwaukee · Kenosha · Elgin · Waukegan
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
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, Maplewood, Downtown Madison, Wingra Park — and every surrounding area.
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