19.66.080 Retaining walls and rockeries.
A. Building Permit. A building permit is required for retaining walls or rockeries not exempted from permit by Section 105.2 of the International Building Code or the International Residential Code, AMC Chapter 19.14, International Codes.
B. Drainage Control. Drainage control must be provided for the area behind retaining walls and rockeries.
C. Retaining Wall and Rockery Terracing Standards.
1. This subsection (C) applies to any combination of constructed retaining walls or constructed rockeries located within a required setback and used to protect a cut or cuts or used to raise grade and protect a fill slope.
2. If the total height of the retaining wall or rockery exceeds five feet, the retaining wall or rockery must be terraced as shown in Figure 19.66.080(C).
DEPARTURES for alternative terracing dimensions will be considered where natural topographic or geologic features make compliance with this section infeasible.
3. The Director may require the retaining walls or rockeries to be designed by a structural engineer if drainage issues, unstable soils, or other structural concerns are present.
Terraced retaining wall example |
D. Standards for Fences on and near Retaining Walls and Rockeries.
1. Retaining Walls or Rockeries Less Than Five Feet in Total Height.
a. Fences may be located on top of retaining walls or rockeries, provided the maximum fence height complies with Table 19.66.030.
2. Retaining Walls or Rockeries Five Feet in Total Height or Greater.
a. In required rear and side setbacks only, a fence may be placed on top of retaining walls and rockeries, provided the total combined height of the retaining wall or rockery and the fence is less than 12 feet.
b. In all required setbacks, the total combined height of the retaining wall or rockery and the fence may be 12 feet or greater, provided the fence is set back at least five feet from the edge of the retaining wall or rockery.
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E. Standards for Large-Scale Manufactured Blocks Used for Retaining Walls (e.g., Ecology Blocks or Jersey Barriers).
1. Such blocks are prohibited for construction of retaining walls in all residential zones, the CBD zone, and the C zone.
2. In all other zones, such blocks may be used for retaining walls, provided retaining walls greater than four feet in height incorporate decorative materials, stamped patterns, or other treatments which create visual interest approved by the Director. (Ord. 3040 § 2 (Att. A), 2019)