Florissant, MO Fence Regulations: Retaining Walls (2026)

070 address retaining walls in two places. 2 exemption list, a retaining wall does not need a building permit if it is two feet or less in height, measured from the bottom of the footing to the top of the wall, unless the wall supports a surcharge load, in which case a permit and engineering are required regardless of height. 5, added specifically for Florissant, imposes a life-safety guard requirement independent of the permit exemption: wherever a retaining wall creates a grade difference of more than thirty inches between its high and low sides, and the high side sits closer than two feet to a walk, path, parking lot or driveway, the property owner must provide a guard.

This closes the gap created by the permit exemption: a wall can be short enough to skip the permit process yet still tall enough, relative to a nearby walking or parking surface, to require fall protection. 2 of the International Building Code. Walls taller than two feet, or any wall of any height that supports a surcharge such as a driveway, patio or structure above it, need a full permit application with construction plans before work begins.