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By: Bill Davis

September 24, 2020

As Engineers and Architects, we consistently hear the following question floating around the industry: “does replacing a roof require a permit?”. And more recently, “does replacing a roof require the installation of a green roof and/or a photovoltaics, known as a “sustainable roofing zone’?” The code can be overwhelming and confusing to the laymen, and this article will attempt to clarify and delve deeper into this issue that will inevitably affect building owners and property managers all over New York City at some point during a building’s service life.

RCNY 101-14, Chapter 100, Table 2 section IV Roofs item #1. states, Roof repair and reroofing ABOVE the deck/sheathing. Roof repair or replacement, limited to the roof membrane, roof coverings, cant strip, and any insulation ABOVE the roof deck/sheathing, provided that the New York City Energy Conservation Code does not require additional thermal insulation for the roof.

Believe it or not, a permit is not required under the very specific set of circumstances listed above. However, it is extremely rare to replace a roof in New York City and not have to perform at least, limited, “roof deck” repair. “Roof deck” has proven to be a nebulous and debatable term. The roof deck supports the roofing membrane and insulation and is typically comprised of wood planks, wood sheathing, or concrete that is supported by wood joists or steel beams. In older wood framed buildings, wood decking is notoriously susceptible to deterioration, which typically requires repair during a roof replacement project. Concrete, on the other hand, inherently has some water resistance qualities, however, typically still requires spot repair in older construction. NYC DOB Bulletin 2019-010 goes even deeper into the term “roof deck” in an attempt to clarify Local Law 92 and 94 of 2019, which indicates that buildings replacing a “roof assembly” must be provided with a green roof and/or photovoltaics or a “sustainable roofing zone.” It is in this document that the term “roof deck” is defined as the structural surface to which the roofing and waterproofing system (including insulation) is applied to. In laymen’s terms, this means that a sustainable roofing zone is only required if the entire roof deck is being replaced which is extremely rare, or when a new building is being constructed, or a substantial portion of the roof deck is being opened to accommodate an addition.

To complicate things further, the New York City Energy Conservation Code (EEC) almost always comes into play, as additional insulation is almost always required. This is related to that fact that the NYC ECC is constantly changing, and buildings are required to lessen their impact on the heat island effect. This will almost always trigger the requirement for filing and a DOB permit.

Sometimes, building owners choose to install a new roofing system over an existing roofing system, or “reroofing,” which typically is a function of budget. In this case, a permit would not be required. However, it is worth noting that 1, this is typically not a recommended solution for several reasons, and 2, this is illegal under the following circumstances per NYC BC 1510.3: Reroofing is not permitted where the existing roof is water soaked or has deteriorated to the point that the existing roof is not adequate as a base for additional roofing and where the existing roof has two or more applications of any type of roof covering. It is advisable to consult a professional when considering a reroofing project to properly assess the conditions of the existing roofing system. Underlying problems may not be obvious or apparent to the untrained eye and installing a roofing system over a compromised membrane can have severe consequences which often lead to more significant problems and more costly repairs in the future.

To be clear, there are very specific and limited occasions where a permit for roof replacement is not required. The first is when a roof membrane is being replaced with no “roof deck” repair and no modification of the existing insulation. The second is reroofing over an existing roofing system.

If a roof replacement project is looming over your building, we recommend reaching out to a professional that specializes in building envelope restoration if you are unsure of whether or not a DOB permit is required.

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