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Retaining Wall HandoutDEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT Persons contemplating the construction of a fence or wall are encouraged to contact the Planning Division for additional information at (425) 430-7200. Always call before you dig! 1-800-424-5555 or www.callbeforeyoudig.com DEVELOPMENT REGULATIONS FOR RETAINING WALLS Planning Division 1055 South Grady Way | Renton, WA 98057 Phone: 425-430-7200 | www.rentonwa.gov This handout has been prepared by the Renton Planning Division to inform you of the City regulations regarding retaining walls. These provisions have been developed in order to promote public safety and aesthetically pleasing neighborhoods. This handout is intended to graphically illustrate these provisions. Do I need a permit to build a retaining wall? A retaining wall that is 4 feet (48”) or taller, as measured by the vertical distance from the bottom of the footing to the finish grade at the top of the wall (i.e., not measured by exposed retaining wall height), always requires a building permit. Building permits also are required for any retaining wall 4 feet or less in height that supports a surcharge (any additional load bearing on or against the wall, such as fill material) behind or above the wall (see Figure 3 below). It is recommended to contact the City Building Section at 425-430-7200 prior to beginning work to determine permit requirements. What materials can I use to build the wall? Retaining walls shall be composed of brick, rock, textured or patterned concrete, or other masonry product that complements the proposed building and site development. Other materials may be used with the Administrator’s approval. How close to the street can I build the wall? There shall be a minimum three-foot (3') landscaped setback at the base of retaining walls abutting public rights-of-way from the property line. Landscaping shall include a mixture of shrubs and groundcover in the 3’ wall setback area (trees are optional) in conformance with the standards of RMC 4-4-070H4, Perimeter Parking Lot Landscaping. However -- per RMC 4-4-070F1 and H1 -- in the remaining 7 feet of required frontage landscaping beyond the wall, “a mixture of trees, shrubs, and groundcover” are required. How tall can a residential wall be? In any residential district, the maximum height of any retaining wall shall be 6 feet (72"), subject to further height limitations as specified below. Can it be 6 feet tall in the front yard too? No, retaining walls cannot exceed 4 feet (48") in height within the front yard setback. What if I have a corner lot? 2 H:\CED\Data\Forms-Templates\Self-Help Handouts\Planning\Retaining Walls Handout.docx Rev: 02/2017 Retaining walls shall not exceed forty two inches (42") in height in any part of the clear vision area as defined by RMC 4-11-030, and shall not exceed 4 feet (48") in height within any part of the front yard setback or side yard along a street when located outside of any clear vision area on said lot. How is the maximum height measured? Provisions of RMC 4-4-040, Fences, Hedges, and Retaining Walls, refer to the “exposed retaining wall height,” which is the vertical distance measure from the finish grade at the bottom of the wall (i.e., lower soil grade) to the finish grade at the top of the wall (see Figures 1 and 2 below). Note that the International Building Code measures from the bottom of the footing to the top of the wall, and any proposed wall taller than four feet (4’) must be designed by a Professional Engineer. What if I need a taller wall? You can terrace your property. Terracing is the act of forming hillside into a number of level flat areas (terraces) between retaining walls.  Terrace Width: No portion of a retaining wall shall be measured as part of the terrace width. The width of a terrace shall be equal to the height of the tallest abutting retaining wall; however, the minimum terrace width shall be two feet (2') and the maximum required width shall be five feet (5'). Terrace width shall be measured from the back edge of the lower retaining wall to the foremost edge of the immediately succeeding and higher retaining wall (see figures 1 and 2 below).  Terrace Landscaping: Terraces created between retaining walls shall be permanently landscaped with a mixture of shrubs and groundcover (trees are optional) in conformance with the standards of RMC 4-4-070F, Landscaping. Landscaping provided in front of retaining walls and within terraces shall contribute to any landscaping required by RMC 4-4-070F; the Administrator may grant exceptions for required trees based on land constraints. How close can I build a fence to a retaining wall? If the fence/hedge would exceed the allowed height of a standalone retaining wall if placed on top of the wall, the fence/hedge shall be set back at least two feet (2') (see figure 1 below). The area between the wall and the fence must be landscaped. Is there a certain distance on either side of the wall that must be flat? Are there limits on how much soil can be on either side of the wall? Unless the wall is designed by a Professional Engineer, the slope of the ground being retained shall be level for a distance of at least one foot (1') for each foot (1') of wall height. Soil may not be placed in front of the wall to reduce the exposed wall height. Can I build a Fence Right on Top of a Retaining Wall? A fence shall not be constructed on top of a retaining wall unless the total combined height of the retaining wall and the fence does not exceed the allowed height of a standalone fence (see figure 2 below). A building permit will likely be required. Are there any exceptions to the combined height limitations? 3 H:\CED\Data\Forms-Templates\Self-Help Handouts\Planning\Retaining Walls Handout.docx Rev: 02/2017 Yes, outside of the front yard area and outside of the clear vision area, it is possible to construct a fence up to six feet (6’), if the fence provides at least fifty percent (50%) transparency, as viewed perpendicularly to the face of the fence. A chain link fence is not eligible for this height limit exception. What if the Building Inspector requires a guardrail at the top of the wall? If the Building Official requires a guardrail, the combined height of the retaining wall and required guardrail shall not exceed nine feet (9') in residential zones, or twelve feet (12') in commercial and industrial zones. How tall can a commercial or industrial retaining wall be? A maximum of eight feet (8') anywhere on the lot provided the fence, retaining wall or hedge does not stand in or in front of any required landscaping or pose a traffic vision hazard. What if these regulations don’t work for my property? Pursuant to RMC 4-9-250D, Modification Procedures, the Administrator may grant modifications to this Section’s retaining wall standards. Approval of a modifications permit may include conditions such as, but not limited to, increased setbacks, additional landscaping, a requirement to terrace or specific materials to be used. Figure 1 4 H:\CED\Data\Forms-Templates\Self-Help Handouts\Planning\Retaining Walls Handout.docx Rev: 02/2017 Figure 2 Figure 3