14R-3-301 The provisions of Section 301 of IEBC are adopted by reference with the following modifications:
Added Coun. J. 4-10-19, p. 100029.
The repair, alteration, change of occupancy, addition or relocation of all existing buildings shall comply with Section 301.2, 301.3, or 301.4.
The alteration, addition or change of occupancy of all existing buildings shall comply with one of the methods listed in Section 301.3.1, 301.3.2 or 301.3.3 as selected by the applicant. Sections 301.3.1 through 301.3.3 shall not be applied in combination with each other.
Alterations, additions and changes of occupancy complying with Chapter 5 shall be considered in compliance with the provisions of this code.
Alterations, additions and changes of occupancy complying with the applicable requirements of Chapters 6 through 12 shall be considered in compliance with the provisions of this code.
Alterations, additions and changes of occupancy complying with Chapter 13 shall be considered in compliance with the provisions of this code.
Relocated buildings shall comply with the requirements of Chapter 14.
Accessibility requirements for existing buildings shall comply with ICC A117.1 as modified by Chapter 11 of the Chicago Building Code.
14R-3-302 The provisions of Section 302 of IEBC are adopted by reference with the following modifications:
Added Coun. J. 4-10-19, p. 100029.
Amended Coun. J. 2-19-20, p. 14474.
Amended Coun. J. 10-7-20, p. 21791.
The provisions of Section 302 apply to all alterations, repairs, additions, relocations of structures and changes of occupancy regardless of compliance method.
The building official shall require the elimination of dangerous conditions. The building official shall have the authority to require the elimination or abatement of unsafe conditions.
Alterations, repairs, additions and changes of occupancy to, or relocation of, existing buildings and structures shall comply with the provisions for alterations, repairs, additions and changes of occupancy or relocation, respectively, in this code and the Chicago Energy Conservation Code, Chicago Fire Prevention Code, Chicago Fuel Gas Code, Chicago Mechanical Code, Chicago Plumbing Code, Chicago Minimum Requirements for Existing Buildings and Chicago Electrical Code. Where provisions of the other codes conflict with provisions of this code, the provisions of this code shall take precedence.
Existing buildings undergoing repair, alteration, change of occupancy, addition or relocation shall also comply with the Chicago Minimum Requirements for Existing Buildings.
Materials already in use in a building in compliance with requirements or approvals in effect at the time of their erection or installation shall be allowed to remain in use unless determined by the building official to be hazardous.
Except as otherwise required or allowed by this code, materials allowed by the applicable code for new construction shall be used. Like materials shall be allowed for repairs and alterations, provided that unsafe conditions are not created. Hazardous materials shall not be used where the code for new construction would not allow their use in buildings of similar occupancy, purpose and location.
New structural members and connections shall comply with the material and detailing provisions of the Chicago Building Code for new buildings of similar structure, purpose and location.
Where determining the appropriate application of the referenced sections of this code, the occupancy and use of a building shall be determined in accordance with Chapter 3 of the Chicago Building Code.
14R-3-303 The provisions of Section 303 of IEBC are adopted by reference with the following modifications:
Added Coun. J. 4-10-19, p. 100029.
Amended Coun. J. 7-24-19, p. 3647.
Amended Coun. J. 2-19-20, p. 14474.
Text changes made to this section by the ordinance adopted February 19, 2020 are reflected in the first printing of the 2019 Chicago Building Rehabilitation Code.
Where an addition or alteration does not result in increased design live load, existing gravity load-carrying structural elements shall be allowed to be evaluated and designed for live loads approved by the building official that are less than those required by Section 1607 of the Chicago Building Code. Any area approved for a reduced live load shall be posted with permanent placards indicating the approved live load. Where the addition or alteration results in increased design live load, the live load required by Section 1607 of the Chicago Building Code shall be used.
Where an alteration or addition changes the potential snow drift effects on an adjacent building, the building official is authorized to enforce Section 7.12 of ASCE 7.
Where required, seismic evaluation or design shall be based on the procedures and criteria in this section, regardless of which compliance method is used.
Where compliance requires the use of full seismic forces, the criteria shall be in accordance with one of the following:
- One-hundred percent of the values in the Chicago Building Code. Where the existing seismic forceresisting system is a type that can be designated as "Ordinary," values of R, Ω0 and Cd used for analysis in accordance with Chapter 16 of the Chicago Building Code shall be those specified for structural systems classified as "Ordinary" in accordance with Table 12.2-1 of ASCE 7, unless it can be demonstrated that the structural system will provide performance equivalent to that of a "Detailed," "Intermediate" or "Special" system.
- ASCE 41, using a Tier 3 procedure and the two-level performance objective in Table 303.3.1 for the applicable risk category.
PERFORMANCE OBJECTIVES FOR USE IN ASCE 41 FOR COMPLIANCE WITH FULL SEISMIC FORCES
| RISK CATEGORY (Based on CBC Table 1604.5) | STRUCTURAL PERFORMANCE LEVEL FOR USE WITH BSE-1N EARTHQUAKE HAZARD LEVEL | STRUCTURAL PERFORMANCE LEVEL FOR USE WITH BSE-2N EARTHQUAKE HAZARD LEVEL |
| I | Life Safety (S-3) | Collapse Prevention (S-5) |
| II | Life Safety (S-3) | Collapse Prevention (S-5) |
| III | Damage Control (S-2) | Limited Safety (S-4) |
| IV | Immediate Occupancy (S-1) | Life Safety (S-3) |
Where seismic evaluation and design is allowed to use reduced seismic forces, the criteria used shall be in accordance with one of the following:
- The Chicago Building Code using 75 percent of the prescribed forces. Values of R, Ω0 and Cd used for analysis shall be as specified in Section 303.3.1 of this code.
- [Reserved]
- ASCE 41, using the performance objective in Table 303.3.2 for the applicable risk category.
PERFORMANCE OBJECTIVES FOR USE IN ASCE 41 FOR COMPLIANCE WITH REDUCED SEISMIC FORCES
| RISK CATEGORY (Based on CBC Table 1604.5) | STRUCTURAL PERFORMANCE LEVEL FOR USE WITH BSE-1E EARTHQUAKE HAZARD LEVEL | STRUCTURAL PERFORMANCE LEVEL FOR USE WITH BSE-2E EARTHQUAKE HAZARD LEVEL |
| I | Life Safety (S-3). See Note a | Collapse Prevention (S-5) |
| II | Life Safety (S-3). See Note a | Collapse Prevention (S-5) |
| III | Damage Control (S-2). See Note a | Limited Safety (S-4). See Note b |
| IV | Immediate Occupancy (S-1) | Life Safety (S-3). See Note c |
- For Risk Categories I, II and III, the Tier 1 and Tier 2 procedures need not be considered for the BSE-1E earthquake hazard level.
- For Risk Category III, the Tier 1 screening checklists shall be based on the Collapse Prevention, except that checklist statements using the Quick Check provisions shall be based on MS-factors that are the average of the values for Collapse Prevention and Life Safety.
- For Risk Category IV, the Tier 1 screening checklists shall be based on Collapse Prevention, except that checklist statements using the Quick Check provisions shall be based on MS-factors for Life Safety.
14R-3-304 The provisions of Section 304 of IEBC are adopted by reference without modification.
Added Coun. J. 4-10-19, p. 100029.
Where used, in-situ load tests shall be conducted in accordance with Section 1708 of the Chicago Building Code.
14R-3-305 The provisions of Section 305 of IEBC are adopted by reference with the following modifications:
Added Coun. J. 4-10-19, p. 100029.
Amended Coun. J. 7-24-19, p. 3647.
Amended Coun. J. 2-19-20, p. 14474.
Amended Coun. J. 10-7-20, p. 21791.
Amended Coun. J. 6-25-21, p. 32180.
The provisions of Sections 305.1 through 305.9 apply to maintenance, change of occupancy, additions and alterations to existing buildings, including those identified as historic buildings.
Exceptions:
- Group R-5 occupancies that are not undergoing a change of occupancy.
- Occupancies that are undergoing a change of occupancy to Group R-5.
A facility that is constructed or altered to be accessible shall be maintained accessible during occupancy.
An alteration of an existing facility shall not impose a requirement for greater accessibility than that which would be required for new construction. Alterations shall not reduce or have the effect of reducing accessibility of a facility or portion of a facility.
Exception: Alterations to individually-owned Accessible units or Type A units within a Group R-2 occupancy shall be allowed to meet the requirements for Type B units.
Existing buildings that undergo a change of occupancy shall comply with this section.
Exception: Type B units required by Section 1107 of the Chicago Building Code are not required to be provided in existing buildings and facilities built for first occupancy before March 14, 1991, undergoing a change of occupancy.
Where a portion of the building is changed to a new occupancy classification, any alterations shall comply with Sections 305.6, 305.7 and 305.8.
Where an entire building undergoes a change of occupancy, it shall comply with Section 305.4.1 and shall have all of the following accessible features:
- Not fewer than one accessible building entrance.
- Not fewer than one accessible route from an accessible building entrance to primary function areas.
- Signage complying with Section 1111 of the Chicago Building Code.
- Accessible parking, where parking is being provided.
- Not fewer than one accessible passenger loading zone, where loading zones are provided.
- Not fewer than one accessible route connecting accessible parking and accessible passenger loading zones to an accessible entrance.
Where it is technically infeasible to comply with the new construction standards for any of these requirements for a change of occupancy, Items 1 through 6 shall conform to the requirements to the maximum extent technically feasible.
Exception: The accessible features listed in Items 1 through 6 are not required for an accessible route to Type B units.
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Unless technically infeasible, provisions for new construction shall apply to portions of existing buildings that are altered concurrently with a change of occupancy to a Group R-4 occupancy or a Group R-1 or R-2 occupancy containing more than 20 dwelling units or sleeping units.
Provisions for new construction shall apply to additions. An addition that affects the accessibility to, or contains an area of, a primary function shall comply with the requirements in Section 305.7. Additions to an existing building shall provide entry from the existing building at all common levels without necessitating leaving and re-entering the building from the outside.
If there are no toilet rooms, bathing facilities or shower rooms in the addition and these facilities are provided in the existing building, then at least one toilet room, one bathing facility and one shower room for each sex, or one unisex toilet room or bathing facility, shall be accessible.
A facility that is altered shall comply with the applicable provisions in Chapter 11 of the Chicago Building Code, unless technically infeasible. Where compliance with this section is technically infeasible, the alteration shall provide access to the maximum extent technically feasible.
Exceptions:
- The altered element or space is not required to be on an accessible route, unless required by Section 305.7.
- Accessible means of egress required by Chapter 10 of the Chicago Building Code are not required to be provided in existing facilities.
- Accessible units and Type A units required in Group R-2, R-3 and R-4 occupancies by Section 1107 of the Chicago Building Code are not required to be provided in existing buildings and facilities undergoing alterations where there is no change of occupancy.
- Type B units required by Section 1107 of the Chicago Building Code are not required to be provided in existing buildings and facilities built for first occupancy before March 14, 1991, undergoing alterations or change of occupancy.
- Type C units shall not be required in existing buildings and facilities undergoing alterations or change of occupancy.
Where an alteration affects the accessibility to, or contains an area of primary function, the route to the primary function area shall be accessible. The accessible route to the primary function area shall include toilet facilities and drinking fountains serving the area of primary function.
Exceptions:
- The costs of providing the accessible route are not required to exceed 20 percent of the costs of the alterations affecting the area of primary function.
- This provision does not apply to alterations limited solely to windows, hardware, operating controls, electrical outlets and signs.
- This provision does not apply to alterations limited solely to mechanical systems, electrical systems, installation or alteration of fire protection systems and abatement of hazardous materials.
- This provision does not apply to alterations undertaken for the primary purpose of increasing the accessibility of a facility.
- This provision does not apply where alterations are limited to dwelling units or sleeping units other than Accessible units or Type A units and means of egress serving such units.
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The provisions of Sections 305.8.1 through 305.8.15 shall apply to alterations to existing buildings and facilities.
Where an alteration includes alterations to an entrance that is not accessible, and the facility has an accessible entrance, the altered entrance is not required to be accessible unless required by Section 305.7. Signs complying with Section 1111 of the Chicago Building Code shall be provided.
Altered elements of existing elevators shall comply with the Chicago Conveyance Device Code and ICC A117.1. Such elements shall also be altered in elevators programmed to respond to the same hall call control as the altered elevator.
Platform (wheelchair) lifts complying with ICC A117.1 and installed in accordance with the Chicago Conveyance Device Code shall be allowed as a component of an accessible route.
Where an escalator or stairway is added where none existed previously and major structural modifications are necessary for installation, an accessible route shall be provided between the levels served by the escalator or stairways in accordance with Section 1104.4 of the Chicago Building Code.
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Where slopes steeper than allowed by Section 1012.2 of the Chicago Building Code are necessitated by space limitations, the slope of ramps in or providing access to existing facilities shall comply with Table 305.8.5.
RAMPS
| SLOPE | MAXIMUM RISE |
| Steeper than 1:10 but not steeper than 1:8 | 3 inches |
| Steeper than 1:12 but not steeper than 1:10 | 6 inches |
For SI: 1 inch = 25.4 mm.
Where Group I-1, I-2, I-3, R-1, R-2 or R-4 dwelling units or sleeping units are being altered or added, the requirements of Section 1107 of the Chicago Building Code for Accessible units apply only to the quantity units being altered or added.
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Where more than 20 Group R-2 dwelling units or sleeping units are being altered or added, the requirements of Section 1107 of the Chicago Building Code for Type A units apply only to the quantity of units being added.
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Where four or more Group I-1, I-2, R-1, R-2, R-3 or R-4 dwelling units or sleeping units are being added, the requirements of Section 1107 of the Chicago Building Code for Type B units apply only to the quantity of units being added.
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In alterations, accessible wheelchair spaces are not required to be located within the defined area of raised jury boxes or witness stands and shall be allowed to be located outside these spaces where the ramp or lift access restricts or projects into the required means of egress.
Where it is technically infeasible to alter existing toilet and bathing rooms to be accessible, an accessible family or assisted-use toilet or bathing room constructed in accordance with Section 1109.2.1 of the Chicago Building Code is allowed. The family or assisted-use toilet or bathing room shall be located on the same floor and in the same area as the existing toilet or bathing rooms. At the inaccessible toilet and bathing rooms, directional signs indicating the location of the nearest family or assisted-use toilet room or bathing room shall be provided. These directional signs shall include the International Symbol of Accessibility and sign characters shall meet the visual character requirements in accordance with ICC A117.1.
In assembly and mercantile occupancies, where additional toilet fixtures are added, not fewer than one accessible family or assisted-use toilet room shall be provided where required by Section 1109.2.1 of the Chicago Building Code. In recreational facilities, where additional bathing rooms are being added, not fewer than one family or assisted-use bathing room shall be provided where required by Section 1109.2.1 of the Chicago Building Code.
Where it is technically infeasible to provide accessible dressing, fitting or locker rooms at the same location as similar types of rooms, one accessible room on the same level shall be provided. Where separate-sex facilities are provided, accessible rooms for each sex shall be provided. Separatesex facilities are not required where only unisex rooms are provided.
Operable parts of replacement fuel dispensers shall be allowed to be 54 inches (1370 mm) maximum, measuring from the surface of the vehicular way where fuel dispensers are installed on existing curbs.
The maximum height of thresholds at doorways shall be 3/4 inch (19.1 mm). Such thresholds shall have beveled edges on each side.
Where the structural or operational characteristics of an amusement ride are altered to the extent that the amusement ride's performance differs from that specified by the manufacturer or the original design, the amusement ride shall comply with requirements for new construction in Section 1110.4.8 of the Chicago Building Code.
All changes, improvements or maintenance of existing parking areas, including sealcoating, resurfacing, remarking, fencing, curbs, walks or landscaping, shall provide accessible parking spaces in accordance with Section 1106 of the Chicago Building Code. In addition, an accessible route shall be provided within the parking area to connect the accessible parking spaces to a path of travel that leads to an accessible entrance. The accessible route shall include the connection from the parking area that leads to the accessible entrance.
In Group I-3 occupancies, at least 3 percent of sleeping units being altered shall comply with Section 1107.5.5 of the Chicago Building Code until 3 percent of total sleeping units in the facility are accessible. Where alterations are made to specific sleeping units, the required number of accessible sleeping units shall be permitted to be provided in sleeping units other than those where alterations are originally planned, provided that each substitute sleeping unit meets all of the following criteria:
- Is located on the same site.
- Is integrated with other sleeping units to the maximum extent feasible.
- Has, at a minimum, equal physical access as the other altered sleeping units to areas used by detainees for visitation, dining, recreation, educational programs, medical services, work programs, religious services, and participation in other programs that the facility offers to detainees.
- If it is technically infeasible to locate a substitute sleeping unit on the same site, the substitute sleeping unit must be provided at another site within the same correctional system.
These provisions shall apply to facilities designated as historic buildings that undergo alterations or a change of occupancy, unless technically infeasible. Where compliance with the requirements for accessible routes, entrances or toilet rooms would threaten or destroy the historic significance of the facility, as determined by the Illinois Historic Preservation Agency in accordance with Section 202.5.1 of the Illinois Accessibility Code, the alternative requirements of Section 202.5 of the Illinois Accessibility Code for that element shall be permitted.
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14R-3-306 The following language shall be inserted as a new Section 306:
Added Coun. J. 4-10-19, p. 100029.
Materials and methods of application used for roof recover and roof replacement shall comply with the requirements of Chapter 15 of the Chicago Building Code. Roof repair not exceeding 25 percent of the surface area of an existing roof may comply with Chapter 4 of this code.
Exceptions:
- Roof replacement or roof recover of existing lowsloped roofs shall not be required to meet the minimum design slope requirement of one-quarter unit vertical in 12 units horizontal (2-percent slope) in Section 1507 of the Chicago Building Code for roofs that provide positive roof drainage.
- Roof replacement or roof recover of existing lowsloped roofs shall comply with the roof insulation requirements for new construction unless the installation of additional insulation above the structural roof deck is infeasible due to the height of existing parapets, equipment curbs, skylight curbs, window sills, door thresholds, and similar elements with flashing into the roof system. In no case shall a roof replacement or roof recover reduce the insulating value of the roof.
- Recovering or replacing an existing roof covering shall not be required to meet the requirement for secondary (emergency overflow) drains or scuppers in Section 1502 of the Chicago Building Code for roofs that provide for positive roof drainage. For the purposes of this exception, existing secondary drainage or scupper systems required in accordance with this code shall not be removed unless they are replaced by secondary drains or scuppers designed and installed in accordance with Section 1502 of the Chicago Building Code.
Reroofing shall comply with the requirements of Section 706.
Exception: For roof repair not exceeding 25 percent of the surface area of an existing roof, structural roof components shall be capable of supporting the roof-covering system and the material and equipment loads that will be encountered during installation of the system.
Roof replacement shall include the removal of all existing layers of roof coverings down to the roof deck.
Exception: Where the existing roof assembly includes an ice barrier membrane that is adhered to the roof deck, the existing ice barrier membrane shall be allowed to remain in place and be covered with an additional layer of ice barrier membrane in accordance with Section 1507 of the Chicago Building Code.
The installation of a new roof covering over an existing roof covering shall be allowed where any of the following conditions occur:
- The new roof covering is installed in accordance with the roof covering manufacturer's instructions.
- Complete and separate roofing systems, such as standing-seam metal roof panel systems, that are designed to transmit the roof loads directly to the building's structural system and that do not rely on existing roofs and roof coverings for support, shall not require the removal of existing roof coverings.
- Metal panel, metal shingle and concrete and clay tile roof coverings shall be permitted to be installed over existing wood shake roofs when applied in accordance with Section 306.4.
- The application of a new protective roof coating over an existing protective roof coating, a metal roof panel, built-up roof, spray polyurethane foam roofing system, metal roof shingles, mineral-surfaced roll roofing, modified bitumen roofing or, thermoset and thermoplastic single-ply roofing shall be permitted without tear off of existing roof coverings.
Exception: A roof recover shall not be allowed where any of the following conditions occur:
- Where the existing roof or roof covering is water soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing.
- Where the existing roof covering is slate, clay, cement or asbestos-cement tile.
- Where the existing roof has two or more applications of any type of roof covering unless approved based on a condition report complying with Section 104 of the Chicago Minimum Requirements for Existing Buildings that establishes the capacity of the roof structure to support additional weight.
Where the application of a new roof covering over wood shingle or shake roofs creates a combustible concealed space, the entire existing surface shall be covered with gypsum board, mineral fiber, glass fiber or other approved materials securely fastened in place.
Existing slate, clay or cement tile shall be allowed for reinstallation, except that damaged, cracked or broken slate or tile shall not be reinstalled. Existing vent flashing, metal edgings, drain outlets, collars and metal counterflashings shall not be reinstalled where rusted, damaged or deteriorated. Aggregate surfacing materials shall not be reinstalled.
Flashings shall be reconstructed in accordance with manufacturer's installation instructions. Metal flashing to which bituminous materials are to be adhered shall be primed prior to installation.
14R-3-307 The following language shall be inserted as a new Section 307:
Added Coun. J. 4-10-19, p. 100029.
Fire escapes shall not constitute any part of the required means of egress in new buildings.
Existing fire escapes shall continue to be accepted as a component in the means of egress in existing buildings only.
New fire escapes for existing buildings may be approved by the building official only where interior or exterior stairways cannot be utilized because of property lines limiting stairway size or because of sidewalks, alleys or roads at grade level. New fire escapes shall not incorporate ladders or access by windows.
Fire escapes shall comply with this section and shall not constitute more than 50 percent of the required number of exits nor more than 50 percent of the required exit capacity.
Where located on the front of the building and where projecting beyond the property line, the lowest landing shall be not less than 12 feet (3658 mm) or more than 14 feet (4267 mm) above grade, and shall be equipped with a counterbalanced stairway to the street. In alleyways and thoroughfares less than 30 feet (9144 mm) wide, the clearance under the lowest landing shall be not less than 14 feet (4267 mm).
The fire escape shall be designed to support a live load of 100 pounds per square foot (4788 Pa) and shall be constructed of steel or other noncombustible materials. Walkways and railings located over or supported by combustible roofs in buildings of Type III and IV construction are allowed to be of wood not less than nominal 2 inches (51 mm) thick. Stair treads and landings shall be so constructed as to prevent accumulation of snow or ice, but the maximum dimension of any opening, through such treads, landings or floors shall not exceed 11/4 inches (32 mm).
Stairways shall be not less than 24 inches (610 mm) wide with risers not more than, and treads not less than, 8 inches (203 mm) and landings at the foot of stairways not less than 40 inches (1016 mm) wide by 36 inches (914 mm) long, located not more than 8 inches (203 mm) below the door. Guards not less than 36 inches (914 mm) in height shall be provided at the open sides of fire escape stairways and landings.
Doors and windows within 10 feet (3048 mm) of fire escape stairways shall be protected with 3/4-hour opening protectives.
Exception: Opening protection shall not be required in buildings equipped throughout with an automatic sprinkler system.
Existing fire escapes shall not be removed unless approved by the building official and fire code official based on a showing that the means of egress remaining after removal of the fire escape will substantially comply with the requirements for number, width, location, access to and enclosure of means of egress in new buildings provided in Chapter 10 of the Chicago Building Code.
14R-3-308 The following language shall be inserted as a new Section 308:
Added Coun. J. 4-10-19, p. 100029.
Where the use of an existing building or part of an existing building is changed to one of the following special occupancies as described in the Chicago Electrical Code, the electrical wiring and equipment of the building or portion thereof that contains the special occupancy shall comply with the applicable requirements of the Chicago Electrical Code:
- Hazardous locations.
- Commercial garages, repair garages and storage garages.
- Aircraft hangars.
- Gasoline dispensing and service stations.
- Bulk storage plants.
- Spray application, dipping and coating processes.
- Health care facilities.
- Places of assembly.
- Theaters, audience areas of motion picture and television studios, and similar locations.
- Motion picture and television studios and similar locations.
- Motion picture projectors.
- Agricultural buildings.
14R-3-309 The following language shall be inserted as a new Section 309:
Added Coun. J. 4-10-19, p. 100029.
Amended Coun. J. 2-19-20, p. 14474.
Where the number of dwelling units or sleeping units within a fire area in a building containing an existing Group R occupancy is increased, the building shall comply with Section 309.1.1 or 309.1.2, as applicable. Any increase in the number of existing dwelling units or sleeping units shall also comply with the Chicago Zoning Ordinance.
Where alterations will increase the number of existing dwelling units or sleeping units by no more than one, the newly-created unit shall not be required to comply with all requirements for new construction provided the following conditions are met:
- The building shall not exceed the maximum number of stories above grade plane based on construction type in Table 309.1.1. Buildings of mixed construction shall be governed by the requirements of the least fire-resistive construction type.
- Where the new unit is in a basement, the basement walls shall be impervious to leakage of underground and surface runoff water and shall be protected against dampness.
- The dimensions of rooms in the new unit shall comply with Section 1207 of the Chicago Building Code.
- The new unit shall be provided with natural light and natural ventilation as required by Sections 1202 and 1204 of the Chicago Building Code.
- The new unit shall have at least the number of exits or exit access doorways required by Section 1006 of the Chicago Building Code. A second means of egress may pass through a room or space containing a heating plant.
- The floor-ceiling assembly between the new unit and an existing unit shall have a fire-resistance rating of not less than 30 minutes or be original lath and plaster construction.
- Walls between the new unit and an existing unit or between the new unit and a corridor or exit stairway shall have a fire-resistance rating of not less than 30 minutes or be original lath and plaster construction.
- The unit shall be separated from incidental uses adjacent to the unit in accordance with Section 509.1 of the Chicago Building Code.
If the number of existing dwelling units or sleeping units in a building has previously been increased in accordance with this section or prior Sections 78.1-22 or 13-200-230 of the Municipal Code, the building and every additional dwelling unit or sleeping unit shall comply with Section 309.1.2.
MAXIMUM NUMBER OF STORIES ABOVE GRADE PLANE
| CONSTRUCTION TYPE | STORIES ABOVE GRADE PLANE |
| IA | UL |
| IB | 11a |
| IIA, IIIA or IV | 4a |
| IIIB | 3 |
| VA | 3a |
| VB | 2 |
| IIB | 1a |
- One additional story is allowed in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 of the Chicago Building Code.
Where alterations will increase the number of existing dwelling units or sleeping units by two or more, the newly-created units shall not be required to comply with all requirements for new construction provided the following conditions are met:
- Conditions 1—8 in Section 309.1.1 shall be met.
- Interior exit stairways shall be enclosed with assemblies having a fire-resistance rating of not less than 2 hours and opening protectives in accordance with the Chicago Building Code. Existing assemblies may be of combustible construction so long as the required rating is provided.Exception: In existing buildings up to 3 stories above grade plane, exit stairways shall be enclosed with assemblies having a fire-resistance rating of not less than 1 hour and existing 13/4-inch (44 mm) thick solid-core wood doors with 13/4-inch (44 mm) rabbeted frames or opening protectives in accordance with the Chicago Building Code.
- Assemblies separating existing units from corridors shall have a fire-resistance rating of not less than 30 minutes.
- Assemblies separating the new units from existing units and corridors shall have a fire-resistance rating of not less than 1 hour.
- Doors between corridors and new and existing dwelling units and sleeping units shall be existing 13/4-inch (44 mm) thick solid-core wood doors with 13/4-inch (44 mm) rabbeted frames, existing doors tested to establish a fire-resistance rating of not less than 20 minutes or new doors in accordance with the Chicago Building Code.
- Doors to exit stairways and doors between corridors and new and existing dwelling units and sleeping units shall be self-closing.
- Incidental uses shall be enclosed in accordance with Section 509.1 of the Chicago Building Code.
- Basement ceiling construction shall comply with Section 605.4 of the Chicago Building Code.
Where an existing Group R occupancy, not previously used as congregate living facilities, is subject to alterations for use as congregate living facilities, the building shall be equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 of the Chicago Building Code.
In Group R occupancies constructed before January 1, 1958, for openings in original exterior walls, the minimum dimension of yards and courts perpendicular to the openings shall be allowed to be 6 inches (152 mm) less than required by Section 1205 of the Chicago Building Code.