17-17-0301 Division of Improved Zoning Lots. No improved zoning lot may be divided into 2 or more zoning lots and no portion of any improved zoning lot may be sold unless all improved zoning lots resulting from the division or sale comply with all the applicable bulk regulations of the zoning district in which the property is located; provided, however, divisions or sales that do not further increase the extent of any existing nonconformity, including a nonconforming setback that is not impacted by the proposed division or sale, shall be allowed.
17-17-0304 Lot Area per Unit. Lot area per unit refers to the amount of lot area required for each dwelling unit on the property. For example, if a minimum lot-area-per-unit standard of 1,000 square feet is applied to 3,125 square foot lot, a maximum of 3 dwelling units would be allowed on the property.
17-17-0305 Floor Area Ratio. The floor area ratio of a building is the floor area of the building divided by the total gross area of the zoning lot upon which the building is located. In the case of planned developments and townhouse developments, the floor area ratio of a building site is the floor area of all buildings on the site divided by the net site area of the building site.
17-17-0305-A For the purpose of calculating floor area ratios, the "floor area" of a building is the sum of the gross horizontal area of all floors in the building measured from the exterior faces of the exterior walls or from the center line of walls separating two buildings. The "floor area" of a building expressly includes all of the following:
1. floor area of any floor located below grade or partially below grade when more than one-half the floor-to-ceiling height of the below-grade (or partially-below-grade) floor is above grade level, provided that below-grade or partially below-grade floors with a clear height of less than 6 feet 9 inches are not counted as floor area;
2. elevator shafts and stairwells on each floor;
3. floor area used for mechanical equipment, except equipment located on the roof and mechanical equipment within the building that occupies a commonly owned contiguous area of 5,000 square feet or more;
4. those portions of an attic having clear height (head-room) of 6 feet 9 inches or more;
5. mezzanines;
6. enclosed porches;
7. floor area devoted to non-accessory parking;
8. parking provided in excess of the maximum accessory parking limits established in Sec. 17-10-0208, provided that each such parking space will be counted as 350 square feet of floor area; and
9. floor area within a principal building that is occupied by accessory uses.
17-17-0305-C Stairway and Elevator Enclosures and Elevator Equipment Penthouses. For the purpose of calculating floor area ratio, the floor area of stairway and elevator enclosures and elevator equipment penthouses shall not be counted as "floor area" in accordance with Section 17-17-0311-C.
17-17-0306-B Permitted Obstructions / Encroachments. Required setbacks must be unobstructed and unoccupied from the ground to the sky except as expressly allowed in Sec. 17-17-0309. All portions of required front setbacks that are not occupied by permitted obstructions (See Sec. 17-17-0309) must be landscaped and preserved as open space.
17-17-0306-C Patio Pits. No terrace or patio more than 2 feet below grade is permitted within 15 feet of the front property line in any RS1, RS2 or RS3 district or within 12 feet of the front property line in any other R district. This provision is not intended to prohibit the installation of a terrace or patio on a lot that has a pre-construction grade more than 2 feet below the top of the curb of the street upon which the lot fronts. Patios or terraces more than 2 feet below grade may be constructed in the front yard outside of the required setback distance established in this section only if such terrace or patio is visually screened from view with landscaping and decorative fencing.
17-17-0306-D Negative Grade Elevation Lots and Allowed Uses. When the existing street grade (curb level) has a positive (+) elevation above the established lot grade and there is no requested negative (–) elevation change or lowering of the established lot grade within the front setback; then, a terrace or patio may be allowed provided that the area within the terrace or patio is landscaped and preserved as open space. A decorative fence must be installed at the front property enclosing the front setback.
17-17-0307-A Measurement. Required rear setbacks are to be measured from the rear property line of the lot on which such structure is located to the furthermost projection of the structure, not including those projections and features allowed within such setback pursuant to Sec. 17-17-0309.
17-17-0307-B Permitted Obstructions / Encroachments. Required setbacks must be unobstructed and unoccupied from the ground to the sky except as expressly allowed in Sec. 17-2-0306-D Sec. 17-2-0306-E or Sec. 17-17-0309.
17-17-0308-A Measurement. Required side setbacks and existing side yards are to be measured from the side property line of the lot on which such structure is located to the furthermost projection of the structure, not including those projections and features allowed within such setback pursuant to Sec. 17-17-0309.
17-17-0308-B Permitted Obstructions / Encroachments. Required setbacks must be unobstructed and unoccupied from the ground to the sky except as expressly allowed in Sec. 17-17-0309.
Obstruction/Projection into Required Setback | Front | Side | Rear |
Obstruction/Projection into Required Setback | Front | Side | Rear |
Accessory buildings used for domestic storage (e.g., sheds and tool rooms) | No | No | Yes |
Air conditioning units, provided the unit is not more than 4 feet in height | No | Yes | Yes |
Arbors and trellises | Yes | Yes | Yes |
Awnings and canopies | Yes | Yes | Yes |
Bay windows that project no more than 3 feet into the setback and are located at least 4 feet above grade at their lowest point | Yes | No | Yes |
Chimneys that project no more than 18 inches into the setback | Yes | Yes | Yes |
Coach houses meeting the requirements of Section 17-2-201-F.* Coach houses that are constructed adjacent to a public alley must be set back at least two feet from the rear property line; provided, however, that this two-foot setback is not required if the coach house is located at least ten feet from the centerline of the alley, as evidenced by a survey or other similar evidence provided by the applicant and deemed acceptable by the Zoning Administrator
* Editor's note – as set forth in Coun. J. 4-21-21, p. 29942, § 3; intended reference is likely Section 17-9-0201-F. Future legislation will correct if needed. | No | No | Yes |
Satellite dish antennas, not exceeding 1 meter in diameter | Yes [1] | Yes | Yes |
Satellite dish antennas, over 1 meter but not exceeding 2.4 meters in diameter | No | No | Yes |
Eaves and gutters projecting 18 inches or less into setback | Yes | Yes | Yes |
Eaves and gutters projecting 3 feet or less into setback | Yes | No | Yes |
Fences and walls (no more than 20% opaque) up to 6 feet in height | Yes | Yes | Yes |
Fences and walls (more than 20% opaque or solid) up to 4.5 feet in height | Yes | Yes | Yes |
Fences and walls (more than 20% opaque or solid) up to 6 feet in height | No | Yes | Yes |
Flagpoles | Yes | Yes | Yes |
Parking spaces, enclosed, provided that (attached or detached) garages that are accessed from alleys must be set back at least two feet from the rear property line (this two-foot setback is not required if the garage is located at least 10 feet from the centerline of the alley, as evidenced by a survey or other similar evidence provided by the applicant and deemed acceptable by the Zoning Administrator) provided further, however, that additions following the rear wall of existing garages shall be permitted regardless of the proximity of the existing garage's rear wall to the rear property line | No | No | Yes |
Parking spaces, unenclosed in RS districts | No | Yes [2] | Yes |
Parking spaces, unenclosed in RT and RM districts | No | No | Yes |
Patios that are not over 4 feet above the average level of the adjoining ground (See Sec. 17-17-0306-C) | No | No | Yes |
Porches and balconies and that are open on at least 3 sides | No | No | Yes |
Recreational equipment (e.g., swing sets and basketball hoops) | No | No | Yes |
Roof projecting from garage over open patio not to exceed 8 feet | No | No | Yes |
Stairs (unenclosed), providing access to a rooftop deck on an accessory building, with a staircase width not exceeding 4 feet, so long as the entire staircase abuts and is parallel to the wall of the accessory building | No | Yes | Yes |
Stairs (unenclosed) providing secondary egress required by the Building Code | No | Yes[3] | Yes |
Sills, belt courses, cornices, buttresses and other architectural features projecting no more than 3 feet into the setback | Yes | Yes | Yes |
Steps no more than 6 feet above Grade that are necessary for access to a permitted building or for access to zoning lot from a street or alley | Yes | Yes | Yes |
Wheelchair lifts and ramps that meet federal, state and local accessibility standards | Yes | Yes | Yes |
[1] Subject to the restrictions of Section 17-9-0203-A.
[2] Permitted only when the parking is accessed from a public street where no alley exists.
[3] Permitted only for townhouse developments.
17-17-0310-A Measurement. Required building separations are to be measured between the furthermost projection of the structures, not including those projections and features allowed within such setback pursuant to Sec. 17-17-0309.
17-17-0310-B Permitted Obstructions / Encroachments. Required separations must be unobstructed and unoccupied from the ground to the sky except as expressly allowed in Sec. 17-17-0309.
17-17-0311-A Measurement. The building height of any principal or accessory building is measured as the vertical distance from grade to the highest point of the underside of the top floor's ceiling joist on a building with a flat roof or to the mean height level between eaves and ridge of a gable, hip, mansard, or gambrel roof. For purposes of this provision, "floor" means any enclosed area with a floor-to-ceiling height of 6 feet 9 inches or more.
1. Stairway and elevator enclosures providing access to occupiable rooftops and elevator equipment penthouses are allowed to exceed the maximum building height in accordance with Section 17-17-0311-C.
2. Solar photovoltaic or solar thermal panels in all districts are allowed to exceed the maximum building height on a building with a flat roof, provided that the panels and supporting structures do not extend beyond the edge of the roof and do not exceed 9 feet in overall height or extend more than 5 feet above the parapet, whichever results in a lesser height.
3. Solar photovoltaic or solar thermal panels in all districts are not considered when determining building height of a building with a gable, hip, mansard, or gambrel roof, provided that the panels and supporting structures do not extend beyond the edge of the roof, do not extend further than 12 inches vertically above the roof surface at any point, and do not extend vertically above the highest ridgeline of the roof.
4. Rooftop wind energy systems shall be considered permitted accessory structures within all districts provided they comply with the height limits and setbacks established in this Section. A rooftop energy conversion system shall consist of a wind turbine(s) and associated equipment for converting wind energy to power. Wind energy conversions systems shall be permitted as rooftop accessory structures provided such structures:
(a) are set back at least 20 feet from the front building line, or in the case of corner lots, at least 15 feet from the front and side building line facing a street.
(b) are limited to a height of no more than 15 feet above the roof or top of the parapet, whichever is greater.
(c) comply with all noise limitations of the Chicago Municipal Code.
5. Pergolas, arbors and trellises located on rooftops of principal buildings or private garages are allowed to exceed the maximum building height, provided that:
(a) on principal buildings less than 80 feet tall, they are set back at least 20 feet from the front building line, or in the case of comer lots, at least 15 feet from the front building line and side building line facing a street.
(b) on principal buildings and private garages, they do not exceed 11 feet in overall height above the rooftop deck or extend more than 8 feet above the parapet, whichever is greater.
1. Stairway and elevator enclosures providing access to occupiable rooftops and elevator equipment penthouses in R, B, C and D districts are allowed to exceed the maximum building height or mandatory planned development height threshold and will not be counted as floor area for the purpose of calculating floor area ratio to the extent indicated in the following table:
District | Enclosure contains | Setback 1 | Maximum Floor Area per enclosure exceeding building height 2 | Maximum Height 3 |
District | Enclosure contains | Setback 1 | Maximum Floor Area per enclosure exceeding building height 2 | Maximum Height 3 |
R | Stairway only | 20'-0" | 200 square feet | 13'-0" |
Elevator only | 20'-0" | 275 square feet | 19'-6" | |
Elevator and Stairway | 20'-0" | 500 square feet | 19'-6" | |
Elevator Equipment Penthouse | 20'-0" | 200 square feet | 13'-0" | |
B, C or D | Stairway only | 15'-0" | 300 square feet | 13'-0" |
Elevator only | 15'-0" | 275 square feet + 175 square feet per elevator car exceeding 1 | 22'-6" | |
Elevator and Stairway | 15'-0" | 575 square feet + 175 square feet per elevator car exceeding 1 | 22'-6" | |
Elevator Equipment Penthouse | 20'-0" | 200 square feet + 175 square feet per elevator car exceeding 1 | 13'-0" | |
[1] Measured from the front building line to the nearest outside face of the enclosure.
[2] Measured in accordance with Section 17-17-0305-A.
[3] Measured from the underside of the top floor's ceiling joist to the highest point of the enclosure structure.
[2] Measured in accordance with Section 17-17-0305-A.
[3] Measured from the underside of the top floor's ceiling joist to the highest point of the enclosure structure.
2. Stairway and elevator enclosures allowed by this section may only contain stairways, elevator shafts, elevator vestibules, landings, and elevator, mechanical, or fire protection equipment. Enclosures for any other purpose may not exceed the maximum building height for the district and must be included in floor area for the purpose of calculating floor area ratio.
3. In the case of corner lots, in addition to the setback required from the front building line a setback equal to one half the distance between side building lines is required from the side building line facing a street to the nearest outside face of the enclosure.
(Added Coun. J. 5-26-04, p. 25275; Amend Coun. J. 3-9-05, p. 44391; Amend Coun. J. 3-29-06, p. 73934, § 1; Amend Coun. J. 9-13-06, p. 84870, §§ 2, 3; Amend Coun. J. 10-31-07, p. 12065, § 1; Amend Coun. J. 10-8-08, p. 40951, § 1; Amend Coun. J. 5-12-10, p. 92103, § 1; Amend Coun. J. 4-13-11, p. 115858, § 1; Amend Coun. J. 11-2-11, p. 12143, § 1; Amend Coun. J. 3-14-12, p. 23152, § 2; Amend Coun. J. 3-29-17, p. 45477, §§ 7, 8; Amend Coun. J. 2-19-20, p. 14473, Art. VI, § 28; Amend Coun. J. 4-21-21, p. 29942, § 3; Amend Coun. J. 7-20-22, p. 50878, § 8; Amend Coun. J. 12-14-22, p. 58278, Art. V, § 2)