Local Laws 92 and 94 of 2019: NYC's Solar and Green Roof Requirements for Roof Replacements

The short version: a full roof replacement now comes with a sustainability requirement attached

If your building is planning a complete roof deck or roof assembly replacement — not a partial re-cover, a full tear-off — New York City has required, since November 15, 2019, that the new roof include a “sustainable roofing zone” covering 100% of the roof (after certain exclusions) with a solar photovoltaic system, a green roof, or a combination of the two. The requirement comes from a pair of companion local laws, Local Law 92 of 2019 and Local Law 94 of 2019, and it’s spelled out in detail in DOB Buildings Bulletin 2019-010.

For the facade-inspection and sidewalk-shed side of the picture, see our briefing slides: Your façade clock and your sidewalk shed. This post goes deeper on the roof side specifically, because for a lot of boards the first they hear of LL92/94 is when their roofing contractor or architect tells them the new roof needs solar panels or a vegetated system, and that’s a design and budget conversation that needs to start before drawings are finalized, not after.

Local Law 94: the core requirement

Local Law 94 of 2019 is the law that actually writes the requirement into the NYC Building Code. It added a new definition of “sustainable roofing zone” to BC 1502.1 and a new BC 1511.2 that applies the 100% coverage requirement. It also amended BC 28-101.4.3 to make clear that “work involving the replacing of an entire existing roof deck or roof assembly” is exactly the trigger that pulls a project into BC 1511.2 compliance, and it tightened the roof reflectance (“cool roof”) standard in BC 1504.9 at the same time.

Per DOB’s own guidance page on LL92/94, the requirement applies to three categories of project:

• New buildings
• New roofs created by a horizontal or vertical enlargement of an existing building
• Existing buildings replacing an entire existing roof deck or roof assembly

DOB’s Buildings Bulletin 2019-010 pins the applicability date to the construction documents, not the physical start of work: projects with construction documents approved on or after November 15, 2019 are subject to LL92/94, unless those documents had already reached BIS job status K (plan-exam partial approval) before that date. If your last roof replacement was filed and approved before that date, it wasn’t subject to this rule — but your next full replacement will be.

A partial re-cover, a recoat, or patch-and-repair work on an existing roof assembly does not trigger the sustainable roofing zone requirement. The trigger is specifically the replacement of the entire roof deck or roof assembly.

Local Law 92: the carve-out for small solar-incapable areas and affordable housing

Local Law 92 of 2019 is the companion law. It amends the same BC 1511.2 that LL94 created, refining the rule for small contiguous roof areas (areas under 200 sq ft, or under 100 sq ft for a Group R building five stories or less, must get solar if the area can support at least 4kW — otherwise a green roof is the fallback).

LL92 also built in a temporary affordability safety valve. For buildings with income-restricted units (under the private housing finance law, the general municipal law, or RPTL 420-c), buildings in the Alternative Enforcement Program, and buildings owned by HPD, compliance with BC 1511.2 was only required “to the extent determined” by HPD for five years after the law’s effective date. That five-year window ran out November 15, 2024; HPD was also required to study and report on affordability impacts and cost-effective compliance pathways by the same date. If your building relied on that carve-out, it’s worth confirming with your design team that the exemption has, in fact, expired for any roof replacement filed now.

How the sustainable roofing zone is actually calculated

The requirement isn’t “100% of the entire roof.” DOB’s Buildings Bulletin 2019-010 walks through a list of exclusions that come out of the roof area before the 100% coverage requirement is applied. The bulletin’s exclusions include:

• Areas required to be kept clear for Fire Code setbacks or rooftop access, including the clearance required by FC 504.4 and 512.3.1
• Areas occupied by rooftop structures, mechanical equipment, towers, antennas, water towers, greenhouses, parapets, guardrails, solar thermal systems, and appurtenances
• Areas occupied by stormwater-management obstructions (cisterns, reuse systems, blue roofs) installed to comply with DEP permits
• Non-complying or voluntarily provided setbacks and terraces, as long as each one is less than 25% of the area of the building’s largest floor plate
• Recreational space integral to the building’s principal use — playgrounds, sports facilities, Quality Housing recreation space, or roof terraces documented on the certificate of occupancy or a DOB-approved filing
• Steep-slope roof areas (greater than 2:12, or 17%) that can’t support 4kW of solar capacity, backed by a shading report and calculations
• Any area DOB determines has site conditions unfavorable to either system — including cases where the building structure can’t carry the added weight, substantiated by a registered design professional’s statement

Once the actual sustainable roofing zone is identified, the compliance path splits by slope and size. A low-slope zone (2:12 or less) of 200+ sq ft (100+ sq ft for a Group R building five stories or less) can be solar, green roof, or a combination — owner’s choice. A low-slope zone smaller than that threshold must get solar capable of 4kW first, falling back to a green roof only if 4kW isn’t achievable. A high-slope zone (over 2:12) needs solar if it can support 4kW; if it can’t, that area is exempt outright. Supporting calculations and a shading report from a qualified contractor (NABCEP, IBEW-NECA, or UL credentialed) or a registered design professional are required any time the filing claims 4kW can’t be met.

Historic buildings aren’t exempt

A common assumption is that a landmarked building gets a pass. It doesn’t. Per Buildings Bulletin 2019-010, a full roof deck or roof assembly replacement on a building subject to Landmarks Preservation Commission (LPC) jurisdiction still triggers LL92/94 — the design just has to clear LPC approval first, before DOB will approve the permit. That sequencing matters for schedule: if your building is landmarked or in a historic district, budget extra lead time for LPC review of the solar array or green roof design on top of the usual DOB filing timeline.

What owners planning a roof replacement should check before design starts

If a full roof replacement is on your capital plan, a few things are worth confirming before your architect or roofing contractor finalizes drawings:

• Confirm the trigger. Is the scope a true full roof deck/assembly replacement, or a partial re-cover? That distinction decides whether LL92/94 applies at all.
• Map the exclusions early. Fire Code access paths, mechanical equipment footprints, existing terraces, and any area with real structural limitations should be identified before the sustainable roofing zone area is calculated — not discovered after a design is drawn.
• Get a structural read. If the building can’t carry the added dead load of a green roof or ballasted solar racking, that needs a registered design professional’s statement early, since it’s one of the few paths to a full or partial exemption under Buildings Bulletin 2019-010.
• Check for landmarks jurisdiction. If LPC applies, build its review into the schedule before you set a demolition or shed date.
• Line up the filing team. A registered design professional is required for the green roof or solar filing itself, and a licensed electrician has to handle the separate electrical permit for any solar installation.
• Ask about the tax abatement. Green roof and solar installations may qualify for a New York State property tax abatement filed alongside the LL92/94 submission — worth pricing into the project’s return, not just its compliance cost.

Altius CM handles roof repair and replacement as part of our building envelope work, alongside facade restoration, parapet and masonry repair, and waterproofing — including the shed and scaffold sequencing that a roof replacement project often needs while the work is underway. If a roof replacement is coming up for your building, loop us in while scope is still being defined, not after drawings are final.

This is general information, not legal advice. Confirm your building’s specific obligations and exemptions with your design professional and the NYC Department of Buildings before finalizing a roof replacement scope.

If you’re also tracking facade inspection deadlines or sidewalk shed rules alongside a roof project, see our guides to Local Law 11 and FISP Cycle 10 filing windows. For a sense of how Altius CM scopes and sequences this kind of work, see how we approach scope of work and our roof repair & replacement service page.

Planning a roof replacement and not sure if it triggers LL92/94? Contact Altius CM and we’ll help you map the scope before you finalize design.