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Roof Assemblies and Rooftop Structures

Baltimore City Code div. Building Codes, pt. II, ch. 15
in effect

Baltimore City Code, Building Codes, Part II, Section 1502 Roof Drainage

Section 1502. Roof Drainage 1502.1 to 1502.4 {As in IBC} 1502.5 General discharge requirements. Gutters, downspouts, and leaders must be provided on all buildings to properly collect, conduct, and discharge the water from their roofs into a storm drain or into the driveway of an alley, street, or other public way. No water from any building may be discharged so as to run or flow over any sidewalk, footway, or any adjoining property, except from window sills, copings, or cornices that project no more than 1 foot (305 mm). 1502.5.1 Exceptions. This § 1502.5 does not apply to: 1. roofs, cornices, copings, or other similar projections that are less than 5 feet (1.52 m), measured horizontally in the line of flow, as long as the water from them is not discharged on any sidewalk, footway, or adjoining property, or 2. awnings or marquees that discharge off the outer edge. 1502.5.2 Methods. Drainage must be conveyed in 1 of the following methods. 1502.5.2.1 Method 1. Drainage may be discharged by piping to a storm drain, to the street or alley, or to an approved water course. The installation of piping, connections to storm drains, etc., must be made in accordance with the plumbing regulations of Chapter 29 {“Plumbing Systems”} of this Code. Any continuous discharge of drainage water into the public right-of-way of such a volume and frequency as to cause ponding or icing is prohibited and must be conveyed to the nearest public storm water drain or inlet through underground piping. 1502.5.2.2 Method 2. Drainage may be discharged not less than 10 feet (3.05 m) from the building, from other buildings, or from any adjacent property line, as long as the discharge is in such a manner as not to allow drainage to cross adjacent property lines or sidewalks. 1502.5.3 Individual downspouts. Gutters of buildings on adjoining properties may not be connected with common downspouts or leaders, but each building must have individual downspouts or leaders on its own property. If a building is more than 4 stories or 50 feet (15.24 m) high, its leader and downspouts must be inside the building’s exterior walls. 1502.5.4 Relief scuppers. Roofs with interior roof drains and enclosed by parapet walls that will impound water must be provided with relief scuppers placed in the parapet wall not more than 6 inches (152 mm) above the roof level. The openings of these relief scuppers must be at least 6 inches (152 mm) in diameter. Each 6-inch (152-mm) diameter relief scupper opening may only serve a roof area of not more than 1,000 square feet (92.9 square meters). 1502.5.4.1 Internal relief drains. Internal relief drains may be used instead of relief scuppers. Internal relief drains must be independent of the required roof drains.

Baltimore City Code, Building Codes, Part II, Section 1504 Performance Requirements

Section 1504. Performance Requirements 1504.1 to 1504.9 {As in IBC} 1504.10 Reflectance. Roof Coverings over conditioned spaces on low-slope roofs (roof slope < 2:12) on newly constructed buildings and additions to existing buildings shall have a minimum 3-year-aged solar reflective index of 78, as determined by the Cool Roof Rating Council. Exceptions: 1. An addition to a roof that supports living vegetation and includes a synthetic, high quality waterproof membrane, drainage layer, soil layer, and lightweight medium plants. 2. Roof areas used as outdoor recreation space by the occupants of the building. 3. An area including and adjacent to rooftop photovoltaic and solar thermal equipment, totaling not more than 3 times the area that is covered with photovoltaic and solar thermal equipment. 4. Limited roof areas as determined by regulations promulgated by the Department of Housing & Community Development. 5. A roof, the area of which is less than 3% of the gross floor area of the building. 1504.10.1 Conflicts. In the event of a conflict between § 1504.10 of this Code and City Code Article 6 {“Historical and Architectural Preservation”}, City Code Article 6 {“Historical and Architectural Preservation”} prevails. (Ord. 24-341 Section 1; Ord. 23-252.)

Baltimore City Code, Building Codes, Part II, Section 1511 Rooftop Structures

Section 1511. Rooftop Structures 1511.1 to 1511.8 {As in IBC} 1511.9 Rooftop decks. Rooftop decks must comply with this § 1511.9 and with Chapter 16 {“Structural Design”} of this Code. 1511.9.1 Materials. Rooftop decks must be constructed with approved materials in accordance with Chapters 19 through 26 of this Code. 1511.9.2 Notice to adjoining owners. If a rooftop deck is to be supported by party walls: 1. the owners of the adjoining properties must be notified in writing, and 2. evidence of this notice must be submitted with the construction documents. 1511.9.3 Construction documents. Construction documents for all rooftop decks must: 1. include dimensional setbacks, and 2. be signed and sealed by a professional architect or engineer licensed in Maryland. 1511.9.4 Clearances. All rooftop decks must maintain all clearances otherwise required by this Code, including Chapter 8 {“Chimneys and Vents”} of the International Mechanical Code and § 230.24 {“Clearances”} of the National Electrical Code. 1511.9.5 Height. No rooftop deck may be raised more than 2 feet (0.61 m) above the plane that is midway between the lowest and the highest points of the roof surface supporting the rooftop deck. 1511.9.6 Setbacks. A rooftop deck must comply with: 1. the minimum setbacks specified in § 1511.9.6.1, and 2. any greater or additional setback requirements established by or under the Baltimore City Zoning Code and any applicable Urban Renewal Plan. 1511.9.6.1 Minimum setbacks. A rooftop deck must comply with the following minimum setbacks: Front Flat Roof – | 8 feet (2.44 m) from face of building wall Gabled Roof – | 6 feet (1.83 m) behind ridge line Mansard Roof (steeply pitched front slope followed by flat roof) – | 6 feet (1.83 m) behind ridge line Sides and Rear | None (Ord. 24-341 Section 1.)
Source: City of Baltimore Department of Legislative Reference, City of Baltimore Law Library (codes.baltimorecity.gov; Open Law Library bulk XML)URL: https://codes.baltimorecity.gov/us/md/cities/baltimore/code/building-codes/II/15Fetched: 10/25/2026

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