Common Questions
About ADUs

ADU costs in Madison and Dane County typically start in the low-to-mid $100,000s for a detached unit, depending on size, complexity, and finish level. Garage ADUs — an ADU above a new detached garage — and attached ADUs can be priced differently than new detached construction. We provide a ballpark cost estimate during the free feasibility check, and fixed pricing before contract signing.

From your first call to Certificate of Occupancy, most ADU projects in Dane County take 4 to 6 months. The timeline includes feasibility (1–2 weeks), design (4–6 weeks), permitting (4–12 weeks, depending on the municipality), and construction (8–16 weeks). Permitting is often the longest variable — we manage this process for you and respond to any plan review comments on your behalf.

Yes. All ADUs in Wisconsin require a building permit, and in most municipalities, zoning approval as well. Permit requirements vary by city and township — Madison's process differs from Fitchburg's, which differs from Mount Horeb's. We prepare and submit all permit applications. You don't deal with the municipality — we do.

Yes. In Madison and most Dane County municipalities, you can rent your ADU to a tenant. Some municipalities have owner-occupancy requirements — meaning you must live on the property (either in the main house or the ADU) while renting the other unit. We flag any municipality-specific restrictions during your feasibility check.

The terms are often used interchangeably. An ADU (Accessory Dwelling Unit) is the legal and zoning designation for a second, self-contained dwelling on a residential lot. A tiny home refers to a smaller-than-average living space. When built on a foundation and permitted as an ADU, a tiny home and an ADU are the same thing. We use both terms — ADU is the code term, tiny home is how most people describe what they're envisioning.

It depends on your municipality. Madison does not require owner-occupancy — you can rent your ADU without living on-site. Many other Dane County municipalities do require it, including Middleton, Fitchburg, and Mount Horeb (where a recorded covenant is required per its March 2026 ordinance). We review the current requirement for your specific address during the feasibility check.

Most single-family and two-family residential lots in Dane County are eligible for an ADU, but eligibility depends on your zoning district, lot size, setbacks, and municipality. The fastest way to find out is the free feasibility check — we review your address and give you a definitive answer.

Every ADU we build includes architectural design, full permitting, mini-split HVAC, all appliances, quartz countertops, luxury vinyl flooring, slow-close cabinetry, French entry doors, and a lifetime composition roof. No allowances, no finish-it-yourself situations. What you see in the contract is what gets built.

A Certificate of Occupancy is the final permit issued by your municipality that certifies your ADU was built to code and is safe and legal to occupy. Every Boundless project is delivered to CO — it's the standard we hold ourselves to on every build.

Possibly — corner lots and irregular lots often have different setback requirements and may have more or less flexibility than standard lots. We analyze your specific parcel during the feasibility check and identify any constraints or opportunities.