Build a Granny Flat in Madison, WI
A granny flat — or ADU — is a fully independent home on your property. We design, permit, and build them across Dane County. Here’s everything you need to know.
Free Feasibility Check →What is a granny flat?
A granny flat is a small, self-contained home built on the same lot as a primary residence. In Wisconsin, it’s officially called an Accessory Dwelling Unit (ADU) — but granny flat, backyard cottage, in-law apartment, and carriage house all refer to the same thing: a separate, permitted dwelling unit on your property.
A granny flat has its own entrance, kitchen, bathroom, and living space. It’s not a finished basement or a converted garage — it’s a complete, code-compliant home, built to the same standard as any new residential construction in Wisconsin.
In Madison and across Dane County, granny flats are legal and increasingly common. Most single-family lots in Madison allow an ADU by right — meaning you don’t need a special permit or variance, just a standard building permit and a design that meets local zoning rules.
Why build a granny flat on your Madison property?
Built by Boundless Tiny Homes — Madison, WI
Boundless Tiny Homes is the only ADU-only design-build firm in Dane County. We design, permit, and build ADUs across Madison, Fitchburg, Middleton, Verona, Sun Prairie, and all surrounding municipalities. Every project is managed from feasibility check through Certificate of Occupancy — one firm, one contract, no handoffs.
Get a Free Feasibility Check →Learn more
Find out what’s possible on your property.
The feasibility check is free — we review your lot, your municipality’s zoning rules, and your goals. Most Madison-area lots qualify.
Get a Free Feasibility Check →