§ 2.6. - SETBACK PLANES.
This subsection prescribes side and rear setback planes in order to minimize the impact of new development and rear development on adjacent properties. A structure may not extend beyond a setback plane except as authorized by subsection D. below. The height of a setback plane shall be measured under the requirements defined in Section 3.4.
A. Side Setback Plane. Except as provided in subsection B. below, an inwardly sloping 45-degree angle side setback plane begins at a horizontal line 15 feet directly above the side property line. The 15-foot height of the horizontal line is established for 40-foot deep portions of the lot beginning at the building line and extending to the rear of the lot, except that the last portion at the rear of the lot may be less than 40 feet deep. See Figures 3 through 5.
1. For the first portion, the 15-foot height of the horizontal line is measured at the highest of the elevations of the four intersections of the side lot lines, the building line, and a line 40 feet from and parallel to the building line.
2. For successive portions other than the last portion, the 15-foot height of the horizontal line is measured at the highest of the elevations of the four intersections of the side lot lines and the appropriate two lines that are 40 feet apart and parallel to the building line.
3. For the last portion, the 15-foot height of the horizontal line is measured at the highest of the elevations of the four intersections of the side lot lines, the appropriate line parallel to the building line, and the rear lot line.
[image omitted; see the official code]
Figure 3: Side Setback Plane Measured From Side Property Line
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Figure 4: (Elevation View) Dividing Lot into 40-foot Portions to Create Side Setback Planes (Rear Setback Plane Not Shown)
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Figure 5: Determining High Points on a Sloping Lot
For each portion of the side setback plane, the 15-foot height of the horizontal line is measured starting from the highest point of the four intersections defining the portion. In this example, topography lines indicate that the lot is sloping downward from the rear to the front of the lot, and from the right to the left. The high points for Portions 1, 2, and 3 are indicated, along with the Building Line.
B. Rear Setback Plane. Except as provided in subsection D., an inwardly sloping 45-degree angle rear setback plane begins at a horizontal line directly above the rear property line at the same elevation as the horizontal line for the last portion of the side setback plane established in paragraph A.3. See Figures 6 through 9.
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Figure 6: (Elevation View) Rear Setback Plane (Level Ground)
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Figure 7: (Elevation View) Rear Setback Plane (Sloping Ground)
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Figure 8: Side and Rear Setback Planes on Level Ground
The side and rear setback planes form a "tent" over the lot, rising from the property lines for 15 feet and then angling in at 45-degree angles from the side and rear. The required front, rear, and side yard setbacks are indicated by the darker shading on the ground.
[image omitted; see the official code]
Figure 9: Side and Rear Setback Planes on Sloping Ground
C. Buildable Area. The buildable area, as defined in Section 3.3., consists of the smallest area within the front, side, and rear yard setbacks; maximum height limit; and the combined side and rear setback planes. See Figures 10 and 11.
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Figure 10: Buildable Area (Combination of Yard Setbacks, Maximum Height Limit, and Setback Planes)
The heavy blue line indicates the "tent" formed by the side and rear setback planes. The buildable area is the smallest area included within the front, side, and rear yard setbacks; maximum height limit; and the combined side and rear setback planes (shown here as the green area).
[image omitted; see the official code]
Figure 11: Buildable Area on Corner Lot
This figure shows the same concept illustrated in Figure 10 but for a corner lot that has a greater street side yard setback requirement. In this example, the minimum required street side yard setback in the underlying zoning district is 15 feet. Because the side setback plane is measured from the side property line, the height of the setback plane is 30 feet at the 15-foot street side yard setback line.
D. Side and Rear Setback Plane Exceptions for Existing One-Story Buildings.
1. Except as provided in paragraph 3 below, an applicant proposing to add a second story to a one-story building may choose either of the following side setback planes for the portion of the project that is within the building footprint originally constructed, or permitted for original construction, before October 1, 2006:
a. The side setback plane required under subsection A.
b. The inwardly sloping 45-degree angle side setback plane that begins at a horizontal line directly above the outermost side wall at a height equal to the height of the first floor wall plate that was originally constructed or received a building permit before October 1, 2006, plus 10 and one-half feet. See Figure 12. The wall plate is the lowest point of the existing first floor ceiling framing that intersects the exterior wall.
2. Except as provided in paragraph 3 below, an applicant proposing to add a second story to a one-story building may choose either of the following rear setback planes for the portion of the project that is within the building footprint originally constructed, or permitted for original construction, before October 1, 2006:
a. The rear setback plane required under subsection B.
b. An inwardly sloping 45-degree angle rear setback plane that begins at a horizontal line directly above the rear property line at a height equal to the height of the first floor wall plate that was originally constructed or received a building permit before October 1, 2006, plus 10 and one-half feet.
3. The side setback plane required under subsection A, and the rear setback plane required under subsection B, apply to:
a. any portion of the proposed construction that is outside of the building footprint originally constructed, or permitted for original construction, before October 1, 2006; and
b. the entire project, if any portion of the proposed construction requires the removal or demolition of exterior walls.
[image omitted; see the official code]
Figure 12: Side Setback Plane Exception for Existing Single-Story Buildings
The side setback planes for an existing single-story building are determined based on the height of the sidewall. In this example, the horizontal line that forms the base of the setback plane is placed ten feet and six inches above the sidewall height (12 feet). The revised plane rises above the standard setback plane within the area of the building footprint. The standard setback planes created in Sections 2.6. A. and B. apply outside of the existing footprint.
E. Exceptions. A structure may not extend beyond a setback plane, except for:
1. A roof overhang or eave, up to two feet beyond the setback plane;
2. A chimney, vent, antenna, or energy conservation or production equipment or feature not designed for occupancy; and
3. Either:
a. 30-Foot Side-Gabled Roof Exception. A side-gabled roof structure on each side of the building, with a total horizontal length of not more than 30 feet, measured from the building line along the intersection with the side setback plane (See Figure 13.); or
b. Gables Plus Dormers Exception.
(i) Gables or a shed roof, with a total horizontal length of not more than 18 feet on each side of the building, measured along the intersection with the setback plane (See Figures 14 and 17.); and
(ii) Dormers, with a total horizontal length of not more than 15 feet on each side of the building, measured along the intersection with the setback plane. (See Figures 15 and 16.)
[image omitted; see the official code]
Figure 13: Side-Gabled Rood Exception
A side-gabled roof may project through the side setback plane for a horizontal distance of up to a maximum of 30 feet, measured from the building line. In this example, the gable intrudes into the setback plane beginning 9 feet behind the building line. Therefore, the maximum length of the gable intrusion would be 21 feet.
[image omitted; see the official code]
Figure 14: 18-foot Exception for Shed Roof
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Figure 15: Dormer Exception (Gable or Shed)
One or more dormers with a combined width of 15 feet or less on each side of the roof may extend beyond the setback plane. The width of the dormer is measured at the point that it intersects the setback plane.
[image omitted; see the official code]
Figure 16: Dormer Exception (Gable or Shed)
One or more dormers with a combined width of 15 feet or less on each side of the roof may extend beyond the setback plane. The width of the dormer is measured at the point that it intersects the setback plane.
[image omitted; see the official code]
Figure 17: Combination of Roof and Dormer Exceptions
Source: Ord. 20060216-043; Ord. 20060309-058; Ord. 20060622-022; Ord. 20060928-022; Ord. 20080618-093; Ord. No. 20150507-042, Pt. 2, 5-18-15.
