Ames, IA Building Setbacks & Zoning: Lot Coverage Limits (2026)

Ames Municipal Code Sec. 29.401(2), Maximum Building Coverage, applies coverage standards to Principal and Accessory Buildings and to areas used for outdoor storage, with the applicable percentage set out in the Zone Development Standards Table for each Base Zone; some zones add a Minimum Building Coverage floor, and Overlay Zones can carry their own limits in a Supplemental Development Standards Table. Table 29.701(3), the RL Residential Low Density Zone Development Standards table, sets Maximum Building Coverage at 35% of lot area for a single-family dwelling and 40% for a two-family dwelling.

The same table separately caps Maximum Site Coverage, defined to include all buildings, paving, and sidewalks on the lot, at 60% for both housing types, and requires a Minimum Landscaped Area of 40%. Because Site Coverage folds in driveways and walkways along with rooftops, it works as the City's impervious-surface ceiling for RL-zoned lots: a homeowner who has already used the 35% building allowance still has to keep paved area low enough that total coverage stays at or under 60%. Other Base Zones, Floating Zones and Overlay Districts carry their own Building and Site Coverage figures in their respective tables under Sec.

29.401(2), so the percentage differs by zone but the same lot-configuration section governs the standard citywide. Enforcement runs through the Zoning Enforcement Officer in the Planning and Housing Department, and development exceeding the coverage figures in its zone's table is a violation of Chapter 29.