(a) Number of Principal Buildings Per Lot.
(1) In the RR, ER, R-1, and R-1A Districts, only one principal building may be permitted on any single lot unless approved as a condominium or as a small-scale planned housing development. There can be more than one (1) principal building on an individual lot in these residential districts if the buildings contain nonresidential uses as may be allowed in the applicable zoning district.
(2) There can be more than one principal building on an individual lot in the R-2, R-3, and R-4 Districts as well as on an individual lot in all nonresidential districts.
(3) Where multiple buildings are permitted on the same lot, all buildings shall be considered as one (1) building for the purposes of determining the front, side, and rear yard setbacks.
(4) The number of principal buildings per lot in a PD District shall be as approved allowed by the approved PD plans.
(5) Where multiple buildings are permitted on the same lot, there shall be a minimum separation distance of twenty (20) feet.
(b) Minimum Lot Area, Street Frontage, and Lot Width.
(1) Measurements.
A. The area of a lot includes the total horizontal surface area within the lot's boundaries (lot lines).
B. No lot shall be reduced in area or dimensions so as to make said area or dimensions less than the minimum required by this code; and, if already less than the minimum required by this code, said area or dimensions shall not be further reduced. Exceptions to this standard shall only be granted if a reduction is approved as part of a PD or variance approval.
C. Unless otherwise stated, the lot width is the distance between the side lot lines measured along the minimum front yard setback line. For a corner lot, the lot width is the distance between the street right-of-way line and the side or rear lot line provided that at least one of the lot widths complies with the larger lot width requirements in Table 1105-3.
D. Street frontage shall be measured as the length of the right-of-way line along the front lot line, following the line of any curves, if applicable. The minimum street frontage standard shall only be required for one street frontage in the case of corner lots or double frontage lots.
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Figure 1105-A: Illustration of the location for measuring the lot width and street
frontage on a typical interior lot (left) and on a corner lot (right).
(2) Lot Area, Lot Width, and Street Frontage Requirements.
A. Table 1105-3 establishes the minimum lot area and lot width requirements for individual zoning districts.
B. There are no minimum lot area or lot width requirements for the NC, CB, GB, LI, GI, or PI Districts but such lots shall be of a size large enough to allow for all proposed buildings and required setbacks, off-street parking, loading, and stacking spaces, and all landscaping and screening requirements established in this code. Lots in these districts shall have a minimum street frontage as established in Table 1105-3.
C. Minimum lot areas and lot widths in a PD District shall be as established in the PD approval process.
District | Uses | Minimum Lot Area (Square feet) [1] | Minimum Street Frontage [2] | Minimum Lot Width (feet) | |
Corner Lots [3] | All Other Lots | ||||
RR | All Uses | 87,120 (2 acres) | 75 | 250 | 250 |
ER | All Uses | 15,000 | 75 | 120 | 100 |
R-1 | All Uses | 8,500 | 75 | 80 | 75 |
R-1A | All Uses | 5,000 | 40 | 50 | 40 |
R-2 | Two-Family Dwelling | 4,500 per dwelling unit | 75 | 80 | 75 |
All Other Uses | 8,500 | 75 | 80 | 75 | |
R-3 | Single-Family Dwelling | 8,500 | 75 | 80 | 75 |
Two-Family Dwelling | 4,500 per dwelling unit | 75 | 80 | 75 | |
All Other Uses | 3,600 per dwelling unit or 10,000 for all nonresidential uses | 75 | 100 | 100 | |
R-4 | Single-Family Dwelling | 5,000 | 40 | 40 | 40 |
Two-Family Dwelling | 7,000 | 50 | 50 | 50 | |
All Other Uses | 3,600 per dwelling unit or 10,000 for all nonresidential uses | 75 | 100 | 100 | |
OB | Single-Family Dwelling | 8,500 | 75 | 80 | 75 |
Two-Family Dwelling | 4,500 per dwelling unit | 75 | 80 | 75 | |
Multi-Family Dwelling | 3,600 per dwelling unit | 75 | 100 | 100 | |
All Other Uses | None | 75 | None | None | |
NC, CB, GB, LI, GI, or PI | All Uses | None | 75 | None | None |
NOTES: [1] Knox Public Health is authorized to require a larger lot area, beyond the requirements of this table, where on-site sewage treatment is required. [2] The minimum street frontage may be reduced to 40 feet for lots that have frontage on cul-de-sacs or other curved streets. [3] This lot width shall only apply to one lot width measurement on a corner lot (See Section 1105.05(c)(3)B.). The other lot width shall be required to comply with the minimum lot width for all other lots in this table. | |||||
(c) Minimum Setbacks and Yards.
(1) Setbacks and Yards Required for Buildings.
A. A yard is the open area created by the required setbacks. Where required, a yard for any structure shall be located on the same lot as the structure and shall not include any yard or open space areas from an adjacent lot.
B. While a yard is defined as an open area, certain structures and uses may be permitted in required yards as specified in this code.
C. Where the term "required" is used before any yard type, that required yard shall be the area of the yard between the applicable lot line and the required yard setback distance from the applicable lot line, regardless of the presence of a building. See Figure 1105-B.
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Figure 1105-B: The above image illustrates the use of the term “required yards” on a typical interior lot versus the location of the full front, side, and rear yards as defined in the next sections of this code.
(2) Measurements and Exceptions.
A. Setbacks refer to the unobstructed, unoccupied open area between the foundation or base of a structure and the property line (lot line) of the lot on which the structure is located. Setbacks shall not contain any structure except when in conformance with this code.
B. A setback shall not be reduced in any manner to less than the required dimensions for the district in which it is located, and a setback of less than the required dimensions shall not be further reduced in any manner unless otherwise noted in this code (e.g., nonconforming structures or by variances).
C. Front Yard Exception. Where a principal building is to be constructed on a vacant lot where the next two nearest lots are occupied by buildings of the type and use permitted in the district before the effective date of this code and those buildings front yard setback is less than required by this code, the minimum front yard for the new building may be reduced to the shallowest setback of the existing buildings. In no case shall a front yard setback be reduced to less than ten (10) feet from a front right-of-way. See example in Figure 1105-C.
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Figure 1105-C: The above image illustrates the use of an allowed, reduced front yard setback
when the two nearest lots are occupied by buildings with legal nonconforming front yard setbacks.
D. Projections into Required Yards. Every part of a required yard shall be open to the sky and unobstructed except:
i. As otherwise provided in this chapter;
iii. For landscaping as allowed in this code;
iv. For parking and circulation as allowed in this code;
v. For signage as allowed in this code;
vii. For the ordinary projections that are a part or feature of a building which extends or projects outside of the exterior, enclosing facades. It is intended that certain features may project into required yards, but they shall be regulated so as not to substantially interfere with the reception of sun, light, air and the use of adjacent lots as follows:
a) Allowed heating, ventilations, air conditioning, or generator systems;
b) Architectural features such as a belt course, balcony, cornice, gutter or chimney may project into a front and side yard for a distance of two (2) feet;
c) Entrance features such as an open platform, landing, steps, terrace, or other feature not extending above the first-floor level of a building may extend six (6) feet into a front yard and three (3) feet into a side yard.
d) An unenclosed shelter (e.g., entrance hood or open, but roofed porch), open deck, porch, platform, landing, steps, terrace or other feature that is not fully enclosed and does not extend above the first-floor level of a building may extend:
1) Ten (10) feet into the front yard provided such encroachment does not exceed fifty percent (50%) of the width of the front building facade;
2) Six (6) feet into a front yard along the entire width of the front building facade; and
3) Three (3) feet into a side yard.
e) An enclosed entry or porch shall not project into any required yard area. See also Section 1108.01(g)(11).
(3) Lot Configurations and Rules for Setbacks and Yards.
A. Interior Lots.
i. Unless otherwise stated, the required minimum front yard setback shall be measured from the street right-of-way or, where a right-of-way is not identified, the front lot line. See Figure 1105-D.
ii. The lot line located directly opposite the front lot line, shall be the rear lot line and the rear yard setback shall be applied. See Figure 1105-D.
iii. All other lot lines shall be considered the side lot line and the side yard setback shall be applied. See Figure 1105-D.
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Figure 1105-D: Typical setback and yard locations for an interior lot.
B. Corner Lots. Lots that have street frontage on two (2) intersecting streets shall be considered a corner lot, subject to the following:
i. Unless otherwise stated, the required minimum front yard setback shall be measured from both street rights-of-way or, where a right-of-way is not identified, the front lot line. See Figure 1105-E.
ii. The lot line that runs parallel with the front facade of the building on the rear of the lot shall be the rear lot line, and the minimum rear yard setback shall be applied from such lot line. See Figure 1105-E.
iii. All other lot lines shall be a side lot line, and the minimum side yard setback shall be applied from such lot lines. See Figure 1105-E.
iv. An alley shall not be considered a street for the purposes of determining a corner lot.
v. Such setbacks and yard locations shall apply, regardless of the orientation of the building.
vi. Buildings on corner lots should be oriented to face the street on which the lot has the narrowest frontage but may also be oriented toward the corner of the lot, in which case, the setbacks and yard locations shall be as illustrated in Figure 1105-F.
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Figure 1105-E: Typical setback and yard locations for a corner lot.
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Figure 1105-F: Typical setback and yard locations for a corner lot where the
building is oriented toward the corner of the lot.
C. Double Frontage (Through) Lots. Double frontage lots shall be discouraged and shall only be approved if necessitated by unique topographic features or other special physical conditions as deemed necessary by the MPC. Double frontage lots shall be subject to the following regulations:
i. Where a lot is considered a double frontage (through lot) lot, the required minimum front yard setback shall be provided on all lot lines that abut a street. See Figure 1105-G.
ii. Accessory building setbacks in the rear yard may be set back a distance equal to half the required rear yard setback.
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Figure 1105-G: Typical setback and yard locations for a double frontage (through) lot.
iii. The remaining lot lines not abutting a public road right-of-way shall be considered as side yards and shall have the required minimum side yard setback provided for each side lot line. See Figure 1105-G.
iv. For the purposes of allowing accessory uses and fences, which are allowed in a rear yard, the yard that is located to the rear of the principal building shall be considered the rear yard and the setbacks of Section 1105.05(c) shall apply to all accessory uses or structures. And the maximum height of fences shall be as allowed in rear yards in Section 1109.03. Such accessory uses or structures shall not be permitted in the required front yard areas adjacent to each street.
v. Where alleys exist in the City, any lots that have frontage along the alley shall not be considered a double frontage (through) lot and shall either be regulated as an interior lot or corner lot depending on the location of the subject lot within the block.
D. Panhandle (Flag) Lots. Panhandle (flag) lots shall be discouraged and shall only be approved if necessitated by unique topographic features or other special physical conditions as deemed necessary by the MPC. Panhandle (flag) lots shall be subject to the following regulations:
i. Panhandle (flag) lots shall not be used to avoid the construction of a street.
ii. The area of the "panhandle" portion of the lot connecting the lot to the public street shall not be included in the area of the lot for the purposes of determining compliance with the required minimum lot area for the district in which the lot is located.
iii. The stacking of panhandle (flag) lots shall be prohibited. See Figure 1105-H.
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Figure 1105-H: The above illustration shows the stacking of panhandle lots, which is prohibited.
iv. The panhandle shall have a minimum width of fifteen (15) feet along the entire width of the panhandle for lots that contain a single-family residential dwelling. The panhandle shall have a minimum width of twenty-five (25) feet along the entire width for lots that contain any other use. The maximum width shall be forty (40) feet and anything with a width of forty (40) feet or greater shall be consider an interior, corner, or double frontage lot as may be applicable.
v. No structures, except for fences and walls allowed by this code, shall be permitted in the panhandle portion of the lot.
vi. The minimum front yard setback requirement shall be measured from the lot line that creates the rear lot line of the adjacent lot as illustrated in Figure 1105-I.
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Figure 1105-I: Typical setback and yard locations for a panhandle lot.
E. Cul-de-Sac or Curved-Street Lot.
i. For a cul-de-sac lot or a lot abutting a curved street, the front-yard setback shall follow the curve of the front property line (lot line). See Figure 1105-J.
ii. On a cul-de-sac roadway, knuckle, or eyebrow, the required street frontage shall be required and measured at the street right-of-way on the curve of the cul-de-sac, knuckle, or eyebrow.
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Figure 1105-J: Typical setback and yard locations for a curved street or cul-de-sac.
F. Other Lot Configurations. Where there is an instance of a lot configuration not addressed in the previous sections (e.g., interior, corner, panhandle, etc.), or where there is an atypical building orientation on any lot, the ZEO shall have the authority to make a determination regarding where front, rear, and side yard setbacks are required.
(4) Minimum Setback Requirements.
B. Table 1105-4 establishes the minimum setback requirements for principal buildings in all zoning districts.
District | Setback Requirements (Feet) | ||
Front Yard [1] | Side Yard (Each Side) | Rear Yard | |
Residential Zoning Districts | |||
RR | 40 | 25 | 50 |
ER | 30 | 10 | 30 |
R-1 | 30 | 10 | 30 |
R-1A | 10 | 5 | 25 |
R-2 | 30 | 10 | 25 |
R-3 and R-4 | 30 | 10 for facades without windows or doors. 25 or height of building, whichever is greater, for all other facades | 20 |
Nonresidential Zoning Districts | |||
NC | 30 | 15 [2] | 15 [2] |
CB | 0 [3] | 0 [3] | 0 |
GB | 30 | 15 [2] | 15 [2] |
OB | 30 | 15 for nonresidential uses 10 for residential uses | 15 |
LI | 30 | 20 when adjacent to nonresidential zoning districts. 40 when adjacent to residential zoning districts. | |
GI | 30 | 15 when adjacent to nonresidential zoning districts. 100 when adjacent to residential zoning districts. | |
PI | 30 | 15 | 15 |
NOTES: [1] For corner lots, the front yard setback shall be applied to both street frontages as required in Section 1105.05(c)(3)B. However, the front yard setback on the secondary street (side of building) may be reduced by 10 feet. [2] When lots are adjacent to a residential zoning district, the required setback shall be increased by five feet along the entire lot line that is adjacent to the residential zoning district. [3] There shall be a maximum front and side yard setback of 10 feet. | |||
(d) Maximum Building Height.
(1) Measurement. Where specified in feet, building height shall be measured as the vertical distance from the average grade at the base of the structure to the highest point on the roof, regardless of roof type, excluding architectural features (e.g., vents, cupolas, weather vanes, chimneys, etc.), roof embellishments, or chimney extensions. See Figure 1105-K.
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Figure 1105-K: Example of building height measurement.
(2) Exceptions to Height Limits. The maximum height limits established in this code shall not apply to:
A. Spires, belfries, cupolas and domes, monuments, chimneys, smokestacks, towers, water tanks or other tanks for liquids, radio or television antennae, monuments and other permitted mechanical appurtenances located upon or constructed as an integral part of the principal building for all nonresidential uses provided the height of the feature does not exceed two times the lot width; and
B. Governmentally-owned freestanding water tanks, towers, radio or television antennae, and flag poles.
(3) Maximum Height Standards.
(e) Maximum Building Footprint in the NC District. The maximum square footage of any principal building footprint in the NC District shall be 8,000 square feet.
(f) Minimum Residential Dwelling Size.
(1) Calculation.
A. The minimum floor area of a dwelling unit shall include all finished and habitable spaces including the basement floor area when more than one-half (½) of the basement height is above the finished lot grade level at the front of the building.
B. Garages, outdoor patios, porches, or decks, and accessory buildings shall not be included in the minimum floor area of a dwelling.
C. Such requirements shall only apply to single-family dwellings, two-family dwellings, rowhouse dwellings, multi-family dwellings, and dwelling units located in mixed-use buildings. These requirements shall not apply to hospitals, nursing homes, or similar types of residential uses that are institutional in nature.
(2) Minimum Floor Area Requirements.
A. The minimum floor area for single-family dwellings shall be 500 square feet.
B. The minimum floor area for all other dwelling units shall be 350 square feet.
C. There shall be no minimum floor area requirement for dwelling units in the CB District.
D. Smaller dwelling sizes may be approved as part of a PD District or as part of a small-scale planned housing development review.
(g) Maximum Lot Coverage.
(1) Measurement.
A. Where Table 1105-6 establishes that lot coverage is calculated by building footprints, the lot coverage shall be that portion of a lot, which when viewed directly from above, would be covered by the footprints of principal and accessory buildings. Decks, pervious paver blocks, driveways, patios, parking lots, and structures that are not buildings shall not count toward lot coverage.
B. Where Table 1105-6 establishes that lot coverage is calculated by impervious surfaces, the lot coverage shall be that portion of a lot, which when viewed directly from above, would be covered by the footprints of principal and accessory buildings, vehicular use areas, and other surfaces that are impermeable or substantially impervious to water.
C. The ZEO shall have the final determination of what are considered buildings and the total coverage that is considered impervious surfaces.
(2) Maximum Lot Coverage Standards.
A. Table 1105-6 establishes the maximum lot coverage for all buildings on an individual lot within the applicable district.
Zoning District | Maximum Lot Coverage | Lot Coverage Calculated by: |
RR | 30 percent | Building Footprints |
ER | 40 percent | Building Footprints |
R-1 and R-1A | 40 percent | Building Footprints |
R-2 | 50 percent | Building Footprints |
R-3 and R-4 | 50 percent | Building Footprints |
NC and GB | 90 percent | Impervious Surface |
CB | 95 percent | Impervious Surface |
OB | 50 percent | Impervious Surface |
LI | 70 percent | Impervious Surface |
GI | 85 percent | Impervious Surface |
PI | 85 percent | Impervious Surface |
(Ord. 2024-032. Passed 7-22-24.)