Duluth, MN Fence Regulations: Retaining Walls (2026)

4(B) applies to new retaining walls in every district except two situations: walls serving only one-family and two-family dwellings, and walls that won't be visible from neighboring sites or a public street frontage. Where it applies, any retaining wall over six feet tall must be terraced to minimize visual impact on residents, neighbors, and the public realm, and terracing is capped at three tiers. Each tier must be separated by a terrace at least four feet wide with a maximum 3:1 slope, creating pockets for landscaping, though the building official can administratively approve a narrower terrace where site constraints limit available space.

Those terraces must be vegetated with permanent landscaping to screen the wall and add visual interest, unless a licensed engineer determines the soil conditions are unsuitable because of geologic hazards. 4(B)(2)(f) specifically bars railroad ties, timber, and gabion-type construction. 4(C) also bars building any fence, wall, or retaining wall from scrap or waste materials unless recycled or reprocessed, and limits signage on a retaining wall to a single one-square-foot property identification sign.