Janesville, WI Accessory Structures: Shed & Carport Rules (2026)
Shed permit rules in Janesville, WI, also referred to as storage shed, backyard shed, or accessory building regulations, set size limits, setbacks, and when a building permit is required.
Key Facts
- Max shed size
- 120 sq ft (1-2 family lot)
- Max detached garage
- 750 sq ft
- Max height
- 14 ft, 1 story
- Historic district height
- Up to 22 ft, roof-pitch match only
- Building-to-building spacing
- 5 feet minimum
- Structures per dwelling unit
- 1 accessory building + 1 garage
Summary
In the City of Janesville, a detached garage or accessory building must sit at least five feet from any other building on the lot and comply with district setbacks under Code § 42-362, and cannot exceed 120 square feet unless it qualifies as a garage, capped at 750 square feet.
(2)Except as otherwise regulated herein, any accessory building or structure hereafter erected, altered, enlarged, or moved on a lot shall conform with the following:a.No detached garage or accessory building shall be nearer than five feet from the nearest portion of any other building on the lot.b.All detached garages and accessory buildings must comply with the front yard and corner side yard setback requirements as described within each zoning district.c.No detached garage or accessory building directly adjacent to a principal building shall be less than eight feet from any interior side lot line and ten feet from the principal building. ... (3)No detached garage or accessory building accessory to a residence shall have more than one story or exceed 14 feet in height, measured from floor to peak of roof. ... (6)No accessory building accessory to a one or two family residence shall be greater than 120 square feet in area. No detached garage accessory to a one- or two-family residence shall be greater than 750 square feet in area.
Full Breakdown
Section 42-362 governs accessory buildings, attached and detached garages, structures and uses. Subsection (2) requires that any accessory building or structure be no nearer than five feet from the nearest portion of any other building on the lot, comply with the front and corner side yard setbacks of its zoning district, and, when directly adjacent to the principal building, sit no less than eight feet from any interior side lot line and ten feet from the principal building. Subsection (3) caps height: no detached garage or accessory building accessory to a residence may exceed one story or 14 feet measured from floor to roof peak, though the Building Division Director can allow up to 22 feet for buildings in a Historic Overlay District or on the National Register, solely to match the principal building's roof pitch.
Subsection (6) sets the size limits driving most shed questions: an accessory building serving a one- or two-family residence cannot exceed 120 square feet, a detached garage cannot exceed 750 square feet, and an attached garage cannot exceed the gross living area of the principal building. Subsection (7) limits each dwelling unit in a single- or two-family residence to no more than one accessory building and one detached garage. Attached garages, under Subsection (4), count as part of the principal building and follow principal-building setbacks rather than accessory setbacks.
Violations & Fines
Building an oversized shed, exceeding the one-accessory-building-and-one-garage limit, or placing a structure closer than the five-foot building-to-building or district setback distances is a zoning violation the Building Division enforces at permit review and through property inspections, requiring the structure to be relocated, resized or removed to come into compliance.
Frequently Asked Questions
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Sources & Official References
Other rules in Janesville
How Janesville compares: Shed Permit Requirements by City·Compare Janesville to another location·View the Wisconsin accessory structures overview
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Shed & Carport Rules in Nearby Cities
How other cities in Rock County handle shed & carport rules.