The applicable building energy code that determines the minimum insulation requirements for commercial roofs with insulation entirely above the deck in New York is the State Energy Conservation Construction Code (based on the 2015 International Energy Conservation Code with state-specific amendments). The minimum insulation requirements apply both to new construction and roof replacements on existing buildings.
The minimum requirement for insulation installed entirely above the roof deck is R-30 for all climate zones. This code became effective on October 3, 2016.
Note that local jurisdictions may adopt the NYStretch Energy Code-2020, which requires increased levels of insulation for commercial roofs. Please consult your local jurisdiction to determine whether this code is applicable.
Sample roof assembly diagrams and additional information can be found in PIMA’s New York code fact sheet.