Roof Insulation
NYC Building Code § BC 1508
in effectSection BC 1508: Roof Insulation
1508.1 General.
The use of above-deck thermal insulation shall be permitted provided such insulation is covered with an approved roof covering and passes the tests of NFPA 276 or UL 1256 when tested as an assembly.
Exceptions:
1. Foam plastic roof insulation shall conform to the material and installation requirements of Chapter 26 of this code.
2. Where a concrete roof deck is used and the above-deck thermal insulation is covered with an approved roof covering.
1508.1.1 Cellulosic fiberboard.
Cellulosic fiberboard roof insulation shall conform to the material and installation requirements of Chapter 23.
1508.2 Material standards.
Above-deck thermal insulation board shall comply with the standards in Table 1508.2.
Table 1508.2
Material Standards for Roof Insulation
Material Standard
Cellular glass board ASTM C 552
Composite boards ASTM C 1289, Type III, IV, V or VI
Expanded polystyrene ASTM C 578
Extruded polystyrene ASTM C 578
Fiber-reinforced gypsum board ASTM C 1278
Glass-faced gypsum board ASTM C 1177
Mineral fiber insulation board ASTM C 726
Perlite board ASTM C 728
Polyisocyanurate board ASTM C 1289, Type I or II
Wood fiberboard ASTM C 208
Source: City of New York, Charter, Administrative Code and Rules (American Legal Publishing XML export, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/newyorkcity/latest/NYCadmin/0-0-0-176936Fetched: 10/24/2026