- structural analysis – weight of proposed installation can not exceed the allowed live load + dead load capacity of the roof [we will discuss]
- decking : wood decking can not exceed 10% of the overall roof square footage. Non combustible material can exceed these requirements.
- Fire Dept access
504.4.1 Rooftop access. Access to building rooftops shall be provided as follows:
- For each 12 linear feet (3658 mm) of building perimeter accessible from the frontage space of the building and from any other exposure accessible to fire apparatus, a minimum clearance of 6 feet (1829 mm) in width and 6 feet (1829 mm) in depth from any obstruction shall be provided at the parapet wall or other perimeter of the rooftop. Where such building perimeter is 24 linear feet (7315 mm) or greater, but less than 36 linear feet (10 973 mm), the required clearance openings shall be separated by a distance of not less than 12 linear feet (3658 mm). Where such building perimeter is 36 linear feet (10 973 mm) or greater, the required clearance openings may be contiguous, provided, however, that such contiguous openings shall not exceed 12 linear feet (3658 mm) and shall be separated from other required clearance openings by a distance of not less than 12 linear feet (3658 mm). Each exposure accessible by fire apparatus may be treated separately for purposes of locating clearance openings and otherwise complying with the requirements of this provision.
504.4.2 Rooftop obstructions. Unobstructed space shall be provided on rooftops sufficient to allow firefighting operations, as follows:
1. A clear path of not less than 6 feet (1829 mm) horizontal width and 9 feet (2743 mm) in height shall be provided from the front of the building to the rear of the building and from one side of the building to the other, except that a conduit or pipe in compliance with the requirements of this section may cross such path. Such clear path shall be accessible from each point of the rooftop access from which clearance is required pursuant to Section 504.4.1.
- railings or parapet : must be provided, 44” aff around entire roof. If this is to be considered habitable space, the enclosure will need to be a minimum of 7ft.
- wind considerations – ensure proper securing of any objects, structures, to the roof deck for wind load considerations
- as of May 1st the Dept of City Planning passed a series of zoning proposal changes, Zone Green Text Amendments, that address removing obstacles to building green in NYC; green roof design was included as well, see : http://www.nyc.gov/html/dcp/html/greenbuildings/index.shtml
Other rooftop equipment: In a dense city where space is at a premium, rooftops can serve a wide range of purposes, including managing stormwater, providing recreation space, or generating renewable energy. In addition, systems such as boilers and cogeneration facilities can be safer and more efficient when located on roofs. Key building features such as stair and elevator bulkheads must also be located on roofs. However, zoning districts with contextual height limits restrict the space available for these systems above the maximum building height.
The proposal: Allow low-lying features such as green roofs, recreational decks, other stormwater detention systems and skylights anywhere below the parapet, regardless of building height. A guardrail no more than 30% opaque would be allowed up to 3’6” above the top surface of the roof. Greater volume, similar to what is already allowed in many Special Districts, would be allowed above the maximum building height to accommodate modern bulkheads, with requirements for setback and screening of equipment.