Description
- With rare exceptions, the majority of NYCHA buildings have low-slope roofs, usually laid over concrete slabs, and typically meeting masonry parapets at the roof boundary. Existing roofing may have little or no insulation present. In order to meet current energy codes, replacement roofs will require considerable additional insulation thickness.
- Existing first and second-generation roofing and flashings typically used bituminous products and may be contaminated with asbestos. Lead may be found on bulkhead doors, lintels, and other painted elements such as access ladders. Therefore, removals of existing roofing and related elements must be preceded by testing for asbestos and lead abatement when applicable.
Baseline
- The typical new low slope membrane roof installation will include a vapor barrier, waterproofing base layer, layers of tapered polyisocyanurate insulation to provide overall minimum R-33, a coverboard, and a membrane, either cold fluid-applied reinforced, or a three-ply build-up with SBS cap sheet. New flashings will be installed at all rooftop structures and penetrations. All new membrane or paved roofs receive a high-reflectivity coating to reduce heat gain/heat island effect, and to comply with current Energy Code.
- Parapet Walls and Other Roof Elements – Masonry is labor intensive and requires frequent upkeep. Masonry at the parapet walls carry added importance, as they prevent water infiltration where the roof meets the façade. For more cost-effective and longer-lasting rehabilitation, NYCHA has moved away from repairing or replacing masonry parapet walls where possible and now installs easy-to-maintain metal rails during roof rehabs (see photo and Office of Design sample detail). Whether parapets are removed or retained, the height of new guardrails should be 48” above the roof surface whenever feasible (6” above code required minimum of 42”), to allow for additional insulation expected to be needed in the next generation of roof replacement.
- NYCHA has worked closely with NYC DOB to identify appropriate treatments for the removal and reduction of rooftop structures, such as long-dormant smoke rooms and a height reduction of what used to be incinerator stacks. These flues now generally serve as trash chutes that connect to garbage compactors.
- Comply access requirements with FDNY.
Stretch
- Vacuum Insulated Panels – Where the substantially greater thickness of new rigid insulation is problematic, the alternative of Vacuum Insulated Panels may be appropriate. This technology provides greater insulation values in considerably less thickness, but since panels cannot be cut, may not be suitable on small or irregular areas.
- Green Roofs – In addition to reduction of heat gain & heat island effect, Green Roofs absorb rain, reducing runoff to NYC’s sewer system. Proposals for green roofs may be part of a stormwater management strategy and must be reviewed by NYCHA.
- Solar Roofs – See Solar Roof section for more detail. Rooftop solar arrays can offer many benefits- providing power for a power backup battery, lowering utility costs for LMI New Yorkers through community solar, or improving heat mitigation on a building.
RAD Conversion
- Replace all building roofs with above-deck insulation and assume thermal performance to code minimum (R-33/38). Where feasible and indicated by energy modeling, replace all building roofs with
- Include solar photovoltaic (“PV”) technology, if feasible.
No longer in typical use:
- Spray-insulated Roofs – combine waterproofing and insulation in one system, making this a cost-effective roofing type. They can be installed over existing roofing, which was once considered advantageous where abatement costs were prohibitive. However, they have proven to be very vulnerable to puncture damage and are not recommended at locations accessible to residents. Furthermore, NYCHA typically prefers to abate all hazmats.
- Blue Roofs – This type of roof retains water to reduce runoff. Unfortunately, this roof type is most appropriate at new buildings which can be designed to sustain the greater structural loads imposed.
Relevant Codes & Regulations
NYC Building Code — Roofing Systems
Structural, fire-resistance, and wind uplift requirements
NYC Energy Conservation Code
Thermal performance and roof insulation requirements
FM Global — Roofing Standards
Performance-based standards for roof assemblies
OSHA — Fall Protection
Worker safety requirements for roof access and edges
Strategies
Optimize Performance, Operation & Maintenance of Buildings, Systems & Assets
Prioritize Sustainable Materials, Technologies & Practices
Innovate Adaptive & Resilient Solutions
Last Updated on January 10, 2026 at 8:19 am
