Replacing a roof in NYC and the solar or green roof requirement of Local Laws 92 and 94

What Local Laws 92 and 94 require

Local Laws 92 and 94 of 2019 took effect on November 15, 2019. They apply to new buildings, to new roofs created by enlargements, and to existing buildings that replace an entire existing roof deck or roof assembly. In each case, 100 percent of the roof's sustainable roofing zone must be covered by a solar photovoltaic system, a green roof, or a combination of the two.

Under Buildings Bulletin 2019-010, roofs at every level of the building are covered, and each contiguous roof area is evaluated on its own. The rules apply to one- and two-family houses as well as to larger buildings; the bulletin contains no general exemption for small homes.

Which roofing jobs are covered

The bulletin defines the roof assembly as the roof deck, substrate or thermal barrier, insulation, vapor retarder and roof covering. The roof deck is the structural surface to which the roofing and insulation are applied. The table below reflects how these definitions are generally applied in practice.

A common problem is a deck that turns out to be rotted after the old roofing is removed. A roofing contract for an older building should therefore include an allowance for deck repair and a clear procedure for pausing work and amending the filing if the scope changes.

How the requirement is determined

The outcome depends on the slope of the roof and the size of each contiguous sustainable roofing zone. A low-slope roof has a slope of less than 2 in 12 (about 17 percent); a high-slope roof is steeper.

The 4 kW test is based on panels with an efficiency of at least 15 percent. At that efficiency, 4 kW requires roughly 27 square meters, or about 290 square feet, of panel surface before spacing and access paths are considered. When 4 kW cannot be achieved, the filing must include calculations and a shading report prepared by a qualified contractor (for example, one holding NABCEP certification) or a New York State registered design professional.

Areas excluded from the sustainable roofing zone

The sustainable roofing zone is the roof area that remains after the following exclusions are subtracted.

• Areas that must be kept clear for setbacks or access under the Fire Code, the Construction Codes or the Zoning Resolution, such as the rooftop access pathways required by the Fire Code.
• Areas occupied by bulkheads and other rooftop structures, water tanks, mechanical equipment, antennas, parapets, guardrails, solar thermal systems and equipment access pathways.
• Stormwater management installations, such as cisterns, required under DEP site connection or stormwater permits.
• Setbacks and terraces, provided each setback is less than 25 percent of the largest floor plate.
• Recreational spaces documented on the certificate of occupancy or an approved DOB filing.
• Pitched roofs that cannot accommodate 4 kW of solar capacity, supported by calculations and a shading report.
• Areas where the Department determines that site conditions are unfavorable, including a structure that cannot carry the added load, as documented in a statement by a registered design professional.

As an illustration, a Brooklyn rowhouse roof measuring 20 by 45 feet has a gross area of 900 square feet. If the stair bulkhead, the required fire access areas, the parapet and the equipment together take up about 300 square feet, roughly 600 square feet remains. That is well above the 100-square-foot threshold for a small residential building, so the owner must install solar, a green roof or a combination.

Planning the roof and the solar system as one project

• Settle coverage before demolition. The design professional reviews the existing roof and the roofing scope and determines whether the laws apply.
• Check the structure. Ballasted solar racks and green roofs add dead load; a green roof typically weighs far more than a solar array, and older joist roofs may not support it without reinforcement.
• Build the roof first. The deck, insulation and membrane are installed and inspected before any solar attachments are placed.
• Choose the attachment method with the roofing manufacturer. Penetrating mounts require flashing approved by the manufacturer to keep the membrane warranty in effect.
• Complete both trades in the same mobilization. Removing and reinstalling panels on a membrane that is only a few years old adds cost and can affect the roof warranty.
• Schedule the utility early. Con Edison interconnection and permission to operate are often the longest lead items, and the system cannot be energized before approval.

Co-op and condominium buildings also need board approval and should review the proprietary lease or bylaws for roof rights. For a co-op, the solar property tax abatement is credited to the corporation's tax bill, and any pass-through to shareholders is a decision for the board.

Filing with the Department of Buildings

The work is filed in DOB NOW: Build by a registered design professional. The submission includes roof plans showing the included and excluded areas and the fire access areas, drawings of the solar or green roof installation, and a statement of the anticipated solar capacity.

A solar installation also requires an electrical filing by a licensed electrician, which we arrange through our licensed partner electrical contractor. For landmarked buildings, LPC approval comes first. A request for the solar or green roof property tax abatement is submitted with the related filing; since March 30, 2026, green roof abatement requests are submitted through DOB NOW instead of on the paper form.

Tax abatements and credits in 2026

An abatement reduces property tax owed; it is not a cash refund. DOB and the Department of Finance decide eligibility and amounts. NY-Sun incentives for standard residential projects in the Con Edison and Long Island regions have been phased out, while programs for income-qualified households may remain; check the current NY-Sun program status before signing.

We are contractors, not tax advisors. For questions about credits, abatements and how they apply to your return, consult a CPA such as Copper River Tax (copperrivertax.com).

How we can help

We review the roofing scope and the existing roof, coordinate the coverage determination and filing with a registered design professional, run the 4 kW capacity and shading check, and price the roof and the solar or green roof as one coordinated project. Electrical work for solar is performed by our licensed partner electrical contractor. A copy of an existing roofing proposal or photos of the roof help us prepare an accurate estimate.