CertainTeed FlintBoard® ISO NB Composite Polyisocyanurate/OSB Roof Insulation is a rigid board insulation for use with heavyweight shingles, standing seam metal, tile, slate and single ply roofing systems.

Consult membrane manufacturer for suitability and system requirements.

FlintBoard ISO NB features a closed-cell polyiso core bonded to either 7/16" or 5/8" OSB with a fiber-reinforced felt facer on the bottom side. FlintBoard ISO NB is also available bonded to plywood (CDX and fire-treated available in 5/8" or 3/4") upon request.

FlintBoard ISO NB is a recommended roof insulation in conjunction with CertainTeed Roofing Systems.

Technical Information

FlintBoard ISO NB is offered in a variety of thicknesses, providing long-term thermal resistance (LTTR) values from 6.6 to 25.6. Available in 4' x 4' (1220mm x 1220mm) panels only.

For additional technical resources please refer to the CertainTeed Commercial Roof Systems Manual.


Before installation begins, the roof deck must be firm, well attached, even, clean and dry.

For detailed installation instructions please refer to the CertainTeed FlintBoard product brochure and to the CertainTeed Commercial Roof Systems Manual. Refer also to Technical Bulletin CT-ISO-08-02.

Warranty Details

CertainTeed offers four low-slope roof system warranty options: Limited Warranty on Materials, Limited Warranty on Systems, No Dollar Limit (NDL) Limited Warranty and Full System NDL Limited Warranty.  CertainTeed warranty durations are based on a combination of system specification and product selection.  Additionally, CertainTeed offers a stand-alone FlintBoard Warranty backing the long term R-value, its ability to resist the flow of heat through the board.  Please download an overview of these warranty options for details. Consult with your contractor or CertainTeed Territory Manager to determine which warranty is best for your project.     

CertainTeed offers standard low-slope roof system warranty durations between ten and twenty-five years.  Additionally, Gold Star Contractors can increase warranty durations by 25% by engaging in an Integrity Maintenance Agreement with their client.  

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