17.70.090 Hillside development standards | San Luis Obispo Municipal Code

17.70.090 Hillside development standards.

1. Purpose. The purpose of this section is to implement goals of the Conservation and Open Space and Land Use Elements of the General Plan:

a. To protect and preserve scenic hillside areas and natural features such as the volcanic morros, ridge lines, plant communities, rock outcroppings and steep slope areas that function as landscape backdrops for the community;

b. To avoid encroachment into sensitive habitats or unique resources as defined in the Conservation and Open Space Element;

c. To protect the health, safety and welfare of community residents by directing development away from areas with hazards such as landslides, wildland fires, flooding and erosion; and

d. To protect the city’s scenic setting.

2. Application. The provisions of this section shall apply to all lots and sites that have an average cross slope of sixteen percent or more (see Section 17.70.090(B): Average Slope Calculation). The director may require a survey and slope analysis to determine whether the provisions of this section apply to a specific property or development. Notwithstanding the requirements of this section, a lot created pursuant to the Subdivision Map Act and Title 16 (Subdivisions) of the San Luis Obispo Municipal Code prior to the effective date of this division may be developed with a single unit structure in compliance with other applicable requirements of these zoning regulations.

B. Average Cross-Slope Calculation. Average cross-slope is the ratio, expressed as a percentage of the difference in elevation to the horizontal distance between two points on the perimeter of the area for which slope is being determined. The line along which the slope is measured shall run essentially perpendicular to the contours.

1. Where a site does not slope uniformly, average cross-slope is to be determined by proportional weighting of the cross-slopes of uniformly sloping subareas, as determined by the director.

2. Cross-slope determinations shall be based on the existing topography of the net site area after subtracting the area for any future on-site grading necessary to accommodate proposed right-of-way improvements and other on-site improvements.

3. Cross-slope shall be calculated only for the net area as defined in Section 17.70.110 (Lot Area).

1. General Site Planning Standards. To assist in maintaining a natural appearance for hillsides and ridgelines, each structure shall be located in the most accessible, least visually prominent, most geologically stable portion or portions of the site, at the lowest feasible elevation, and shall, at a minimum, meet the following requirements:

a. See Section 17.70.040(A)(2) (Maximum Development Density—Sloped Sites) for maximum density in hillside areas.

b. See Section 17.70.090(B) (Building Height on Slopes with Sixteen Percent Grade or Greater) for maximum height in hillside areas.

2. Site Access and Driveways. Each driveway shall not have a grade steeper than five percent within ten feet of a garage or carport entry. Driveway finished grade shall not exceed an average of fifteen percent, or twenty percent at any point.

3. Retaining Walls. Retaining walls that are twenty feet in length shall be limited to six feet in height (above ground/visible portion). Retaining walls longer than twenty feet shall be limited to four feet in height (above ground/visible portion). A minimum five-foot horizontal separation is required between retaining walls. For exceptions, see subsection D of this section.

4. Downhill Building Walls. No single building wall on the downhill side of a house shall exceed fifteen feet in height above grade. Additional building height on a downhill side is allowed in fifteen-foot increments, where each increment is stepped-back from the lower wall a minimum of ten feet.

5. Height of Lowest Floor Level, Decks, and Support Structures. See Figure 3-9: Height Limit for Lowest Floor, Decks, and Support Structures.

a. Lowest Floor Level. The vertical distance between the lowest point where the foundation meets grade and the lowest floor line of the structure shall not exceed six feet.

b. Decks. No portion of the walking surface of a deck with visible underpinnings shall exceed a height of six feet above grade.

c. Support Structures. Support structures (e.g., columns, pilings, etc.) below the lowest floor on the downhill side of a house shall be enclosed unless visible structural members are an integral feature of the architectural design. Support structure wall surfaces shall not exceed six feet in height.

Figure 3-9. Height Limit for Lowest Floor, Decks, and Support Structures

a. Single-story and small-scale elements, setbacks, overhangs, roof pitches, and/or other means of horizontal and vertical articulation shall be used to create shade and shadow and break up otherwise massive forms to minimize the apparent size of exterior wall surfaces visible from public rights-of-way.

b. Large flat building planes are prohibited; the spatial arrangement of the building, including roof overhangs, shall be used to achieve alternating light and dark building surfaces that will blend with similar contrasts found in the surrounding natural vegetation.

7. Mechanical Equipment. Mechanical equipment may be placed on rooftops or below a deck only if the equipment is not visible from the public right-of-way or adjacent properties, except for solar collectors that are compatible with the roof line and architecturally integrated with the structure.

8. Fencing. Hillside area perimeter fencing that is visible from off-site vantages, except on side and rear yards that are directly adjacent to living areas on adjacent lots, shall be of a semitransparent, rather than solid, design. Semitransparent material includes, but is not limited to, wrought iron, split rail, and four-inch square welded wire. In side and rear yards between living areas on adjacent lots, solid, opaque fencing is allowed. However, the preference is for a more naturalistic approach to screening in the side yards, with semi-transparent fencing combined with landscaping, or landscaping alone.

D. Director’s Action. The director may grant exceptions to standards of this section as set forth in Chapter 17.108 (Director’s Action), subject the following additional findings:

1. Intent. The director, through a director’s action, may act to approve an exception to the hillside requirements of this section only where the applicant can provide clear and substantiated evidence that there is no practical way to comply with the provisions and that no other feasible alternatives will result in better implementation of other zoning regulations or general plan policies while allowing reasonable use of sites subject to hillside regulations.

2. Application Type. A hillside regulation less than required by this section may be approved by city action on a plan for public facilities approved by the council or on a specific plan, development plan under planned development zoning, land division, use permit, or architectural review. Where one of these types of applications is not otherwise required for the proposed feature, an exception request shall be in the form of a director’s action.

3. Findings. Each director’s action to grant an exception to a required hillside regulation shall be subject to each of the following findings, regardless of the type of project application under which the request is considered:

a. The proposed alternative complies with and furthers the intent of this section; and

b. The proposed alternative provides a design solution that is equivalent to or better than the standards prescribed in this section for quality, effectiveness, durability, and safety; and

c. The location and design of the feature receiving the exception will minimize impacts to scenic resources and will not hinder opportunities for wildlife habitation, rest, and movement; and

d. The exception will not prevent the implementation of city-adopted plans, nor increase the adverse environmental effects of implementing such plans; and

e. There are circumstances applying to the site, such as size, shape, or topography, which do not apply generally to land in the vicinity with the same zoning, that would deprive the property of privileges enjoyed by other property in the vicinity with the same zoning; and

f. The exception will not constitute a grant of special privilege—an entitlement inconsistent with the limitations upon other properties in the vicinity with the same zoning; and

g. The exception will not be detrimental to the public welfare or injurious to other property in the area of the project; and

h. Site development cannot be feasibly accomplished with a redesign of the project or redesign of the project would deny the property owner reasonable use of the property. “Reasonable use of the property” in the case of new development may include less development than indicated by zoning. In the case of additional development on an already developed site, “reasonable development” may mean no additional development considering site constraints and the existing development’s scale, design, or density.

1. Minor Development Review. Hillside development shall require approval of minor development review from the city’s planning division.

2. Design Review. Plans submitted for hillside development shall be reviewed for consistency with the city’s community design guidelines, this section, and general development standards of the zoning regulations. (Ord. 1705 § 17, 2021; Ord. 1650 § 3 (Exh. B), 2018)