Ames, IA Accessory Structures: Shed & Carport Rules (2026)

Sec. 29.408(7)(b) of the Ames Zoning Ordinance governs private garages and accessory buildings, including sheds, in the city's Agricultural, Residential, and Hospital/Medical districts. No detached garage or accessory building may sit in the front yard or in a side yard setback abutting a right-of-way on a corner lot. Interior side yards require the same setback as the principal building, but a one-story garage or accessory building on a corner lot may sit within 3 feet of the side lot line. In the rear yard, the code allows a 3-foot setback from both rear and side lot lines for one-story structures, though two-story accessory structures must meet full side setbacks; where a rear yard abuts the front yard of an adjoining lot, the structure must stay at least 6 feet from that property line for the length of the adjoining lot's required front setback, and no accessory building in a rear yard may sit closer than 15 feet to a lot line abutting a street.

Height is capped at the height of a one-story principal building, or at 80 percent of a taller principal building's height or 20 feet, whichever is lower. Size is doubly limited: a detached garage or accessory building in the rear yard cannot occupy more than 25 percent of the rear yard, and the maximum gross floor area is 900 square feet for a Single-Family Dwelling accessory structure or 1,200 square feet for a Two-Family Dwelling. Cumulative garage door width in Agricultural or Residential districts is capped at 30 feet for single-family lots, with doors under 8 feet, such as those for lawn equipment, exempt.

No detached garage or accessory building may contain habitable space, defined as facilities for sleeping, cooking, and a bathroom, unless approved as an Accessory Dwelling Unit, and construction of the accessory structure cannot precede construction of the principal building on the same lot.