Dane County, WI Building Setbacks & Zoning: Lot Coverage Limits (2026)

Ch. 251(7) sets the lot-coverage ceiling for the SFR-08 (Single-Family Residential, Small Lots) zoning district, the county classification covering compact residential parcels in the unincorporated towns that have adopted Dane County zoning: the limit does not extend inside Madison, Sun Prairie, Fitchburg, Middleton, Verona, Stoughton or Monona, each of which administers its own zoning code. The rule measures the combined footprint of the house, garage, shed, deck and every other building or structure against the lot area, excluding any public right-of-way from that calculation. An interior lot may not carry more than 35% building coverage, while a corner lot gets a slightly larger 40% allowance, matching the same 35%/40% split used one district over in SFR-1 under ch.

252(7)(a) and SFR-2 under ch. 253(7)(a). A second cap applies specifically to accessory structures: under ch. 251(7)(b), no accessory building on the lot can exceed 100% of the footprint area of the principal residence, so a homeowner cannot build a garage or workshop physically larger on the ground than the house itself, even if the overall 35%/40% coverage ceiling still has room. Both limits are checked at the building-permit stage by the county's Planning and Development Department before a zoning permit for new construction, an addition or a new accessory building is issued.