§ 26-126. Detached accessory structures.

Accessory structures shall be permitted in all zoning districts, subject to the floodplain regulations contained in this article, where applicable, in accordance with the following criteria:

(1)

Such detached accessory structures shall not be closer to a side lot line than ten percent of the width of the lot, unless the front line of such accessory structure is situated at least 18 feet behind the front line of the principal structure, in which case the accessory structure may be two feet from the side lot line, except on corner lots, and two feet from the rear lot line. In any case, when the rear lot line abuts an alley, the structure may be built within one foot of the rear property line. However, no portion of the accessory structure, including roof eaves, shall extend across the private property line. On corner lots, accessory structures shall be no closer to the side property line abutting the longer street side of the property than the rear of the required side yard setback in that district, or no closer to the longer street side than the building line of the principal structure, whichever setback is greater. No detached accessory structure shall be allowed in the required front yard of any district.

(2)

Regardless of its location, an unattached accessory structure shall maintain a clearance of eight feet, wall-to-wall, between structures on a single lot.

(3)

An accessory structure serving principal single-unit or two-unit residences shall not exceed 1,024 square feet in area, nor 45 percent of the required rear yard, whichever is less. An accessory structure serving a commercial, professional office, industrial or institutional use, including religious, educational, government, hospital, or nursing homes or convalescent centers shall not exceed 1,200 square feet in area. The maximum allowable square footage of the floor area of accessory structures serving residential uses shall be calculated in the following manner: lot width times required rear yard times 45 percent (LW × RY × 0.45 = maximum allowable square footage). The total allowable square footage calculation shall be based upon the area of the base or "footprint" of the structure.

(4)

In agricultural zoning districts, accessory structures serving principal agricultural uses on properties larger than 20 acres in area shall not be subject to the size or height limitations specified herein. However, on those properties in agricultural districts which contain less than 20 acres in area and where the principal use is residential, the regulations specified herein for residential uses shall apply.

(5)

a.

An accessory building serving a commercial, professional office, industrial or institutional use including religious, educational, government, hospital, nursing homes, or convalescent centers shall not exceed 20 feet in height as measured from the slab floor of the structure to the top of the roof ridge. For all residential uses, including single-unit, duplex, and multi-unit residences, the maximum height of detached accessory structures shall be 18 feet as measured from the slab floor to the top of the roof ridge.

b.

However, on properties containing principal residential structures exceeding one story in height, the residential accessory structure may exceed the 18-foot overall height limitation provided that the structure does not exceed the following components:

1.

Maximum allowable wall height for two opposite walls as measured from the slab floor to the top of the wall is 18 feet.

2.

The maximum overall height of the detached structure, as measured from the slab floor to the roof ridge, shall not exceed 30 feet.

3.

The overall height of the detached structure shall not exceed the height of the principal residence on the property. The height of the principal residential structure shall be determined from the natural grade immediately adjacent to the residential structure to the highest point of the roof ridge of the structure. The natural grade adjacent to the principal residential structure shall be considered to be at a point that represents the prevailing or average grade surrounding the structure excluding the at-grade elevation of an exterior basement entryway.

4.

There shall be no more than two floors, including the base or main floor of the structure, within any detached accessory structure.

(6)

When more than one accessory structure is constructed on a lot, the total floor area of all accessory structures on the lot shall not exceed the area requirements specified in this section.

(7)

In all districts, when additions are made to accessory structures, the entire structure shall thereafter meet all the requirements specified in this section.

(8)

No accessory structure is permitted on any lot unless such lot has a principal permitted use located thereon.

(9)

No portion of an accessory structure shall be allowed to encroach into a public utility easement.

(10)

An accessory structure used in conjunction with a multi-unit residence (three or more dwelling units) shall not exceed a total size of more than 576 square feet in area per dwelling unit, or 45 percent of the total required rear yard, whichever is less.

(11)

The exception to size limitations for detached accessory structures set out in this section shall apply to any lot which measures at least one acre in area, but not more than 20 acres in area, and which contains a principal permitted use located thereon. All detached accessory structures must be located on the same lot where the principal permitted use is located. For any lot which measures one acre or more in area, but not more than 20 acres in area, the maximum allowable sizes of detached accessory structures, as measured by the combined base floor area of all detached accessory structures which are located on the property, shall be limited as follows:

Lot area	Maximum size of all detached accessory structures on lot
At least 1 acre but not more than 2 acres	1,200 square feet
More than 2 acres but not more than 3 acres	1,400 square feet
More than 3 acres but not more than 5 acres	1,600 square feet
More than 5 acres but not more than 8 acres	3,000 square feet
More than 8 acres but not more than 11 acres	4,000 square feet
More than 11 acres but not more than 20 acres	5,000 square feet

 

Each detached accessory structure which measures 1,200 square feet or more in base floor area on any property containing a residential or commercial principal permitted use shall be located on the property at least 18 feet behind the front line of the structure which comprises the principal permitted use on the property. Furthermore, there shall be established a minimum separation of eight feet, as measured wall-to-wall, between each detached accessory structure of any size and each principal structure, and between each such detached accessory structure and any other detached accessory structure of any size located on the property. In addition, each detached accessory structure measuring more than 1,200 square feet in base floor area must satisfy minimum required side yard and minimum required rear yard setback requirements as specified for the zoning district within which the principal permitted use on the property is located. No detached accessory structure of any size shall be allowed within the required front yard area of any property in any district. Building height limitations as specified in this section shall apply to each detached accessory structure, regardless of base floor area dimension.

(12)

a.

Each detached structure which measures 600 square feet or more in base floor area on any property containing a residential principal permitted use shall be located on the property at least 18 feet behind the front line of the structure which comprises the principal permitted use on the property. Furthermore, there shall be established a minimum separation of eight feet as measured wall to wall, between each detached structure of any size and each principal structure and between each such detached accessory structure and any other detached accessory structure of any size located on the property. In addition, each detached accessory structure measuring 600 square feet or larger in base floor area must provide minimum building setbacks of ten feet as measured from the rear yard property boundaries to the base of the detached accessory structure and a side yard setback of ten percent of the lot width as measured from the side property line to the base of the detached structure. In residential districts no detached accessory structure of any size shall be placed in the front yard area of any residential structure. This provision shall not recognize the "required front yard," but shall recognize any portion of the front area of the lot extending from the front lot line and extending to the front line of the principal residential structure.

b.

All pre-existing detached accessory structures that are damaged or destroyed more than 50 percent of their value by fire, flood, tornado, storm, explosion, war, riot, or act of God shall be allowed to be re-established on the same building footprint as previously existed before the damage occurred.

(13)

All detached accessory structures measuring at least 600 square feet in base floor area but no larger than 1,200 square feet in base floor area, which are established in residential zoning districts in compliance with the regulations set forth in this article, shall be consistent with the architectural style of the principal residential structure located on the property at the time such detached accessory structure is established, and shall be required to adhere to the following design guidelines:

a.

The detached accessory structure must utilize similar exterior wall siding materials as then exist on the principal residential structure on the property. Siding panels must approximate the size and dimensions of those siding materials on the principal residential structure. No corrugated metal coverings or siding materials shall be established on the detached accessory structure. No vertical siding materials shall be established unless similar vertical siding materials are then established on the principal residential structure. No steel siding materials shall be permitted unless the principal residential structure then utilizes steel siding materials. In the case of residential structures utilizing brick siding materials, similar brick or masonry materials must be used on the front portion of the exterior walls of the detached accessory structure. Masonry or brick "accents" or trim elements matching similar components on the principal residence are acceptable to complement a residence constructed with brick siding materials. For the remainder of the accessory structure located on a lot with a brick residence, siding materials must resemble siding materials utilized on at least one other non-brick residential structure found on an adjacent property or on the same block in the residential neighborhood if any. In cases where the preceding option is unclear, the proposed structure shall be referred to the planning and zoning commission in conformance with subsection f of this section.

b.

The color and texture of exterior wall materials used on the detached accessory structure must be similar to the color and texture of exterior wall materials on the principal residential structure.

c.

Roof lines and angles on the detached accessory structure must resemble or be similar to the roof lines and angles of the principal residential structure on the property. No flat roofs shall be permitted on the detached structure unless the main residential structure then has a flat roof covering more than half of the residence, excluding a garage or carport flat roof feature attached to the principal residential structure.

d.

Other architectural features of the detached accessory structure must resemble or be similar to features found on the principal residential structure including the size and dimensions of windows. Windows shall be established on at least two walls of detached accessory structures.

e.

Roofing materials utilized on the detached accessory structure must be similar to roofing materials used on the principal residential structure. Metal roofing materials may be utilized only if the principal residential structure on the property then utilizes metal roofing materials.

f.

For preexisting structures that are enlarged or improved resulting in a structure size 600 square feet in base floor area or larger, the entire enlarged or improved structure shall comply with the design and architectural requirements stated herein.

g.

Every property owner applying for a detached accessory structure in a residential zoning district measuring at least 600 square feet in base floor area but no larger than 1,200 square feet in base floor area shall submit to the city planning division office renderings illustrating materials and design characteristics on all four sides of the proposed detached accessory structure, along with then-current photographs of all four sides of the principal residential structure on the property, and a description of the siding and roofing materials and colors of those materials along with a description of the roof pitch on the principal residential structure and how those features compare with the proposed detached accessory structure. City planning division staff shall evaluate the architectural consistency between the proposed detached accessory structure and the principal residential structure based upon the guidelines set forth in this subsection, before issuing a land use permit. In the case of a dispute or uncertainty between city planning division staff and the property owner relating to architectural details or features, or in the event the planning division staff does not approve the architectural/design plans submitted by the property owner, the application for the proposed detached accessory structure shall be submitted to the city planning and zoning commission followed by referral to the city council for architectural/design review purposes.

(Ord. No. 2922, § 1(29-115), 5-7-2018)