FlintBoard ISO HD is a lightweight, high-density polyisocyanurate roof insulation constructed from rigid, closed-cell foam that is integrally-laminated with heavy-coated glass facers for higher dimensional stability. Specifically engineered for use as a roof cover board, it is typically specified for BUR, modified bitumen, and single-ply membrane systems, and performs excellently on adhesive-applied installations.

Technical Information

Each ½" (13mm) FlintBoard ISO HD board offers an R-value of 2.5, and carries a hail rating of SH-1. It is available in both 4' x 4' (1220 mm x 1220 mm) and 4' x 8' (1220 mm x 2440 mm) panel sizes, and has a maximum compressive strength of 109 psi.







Compressive Strenght

ASTM D 1621

Grade 1 (109 psi max)

Dimensional Stability

ASTM D 2126

< 0.5% linear change (7 days)

Water Absorption 

ASTM C 209

< 1% volume

Flame Spread*



Smoke Developed*



Sercive Temperature


260° F or less

Recycle Content


9% - pre-consumer

*Meets the requirements of the IBC code.


The physical properties listed above are presented as typical average values as determined by accepted ASTM test methods and are subject to normal manufacturing variation. This data is offered as a service to our customers, and is subject to change. All information can be confirmed by contacting CertainTeed Commercial Technical Services.

Codes and Compliances

- ASTM C 1289 Type II, Class 4, Grade 1 (109 psi max) UL Classified 790

- UL Class A

- ASTM E108

- FM Approved - consult RoofNav for specific assemblies FM Approved 1-75

- Miami Dade County Product Control Approved

- State of Florida Product Approval No. FL 5968

- California Code of Regulations, Title 24, Insulation Quality Standard License #Tl-1420

UL Classified for use in Canada (Refer to UL Directory of Products Certified for Canada for more details)

- UL Certified for Canada, CAN/ULC-S126, CAN/ULC-S107

- CAN/ULC-S704 Type 3 Class 2


Refer to the CertainTeed FlintBoard product brochure and to the CertainTeed Commercial Roof Systems Manual for installation details regarding FlintBoard Roof Insulation. Refer also to Technical Bulletin CT-ISO-08-02.

Mechanical Attachment - When installing a cover board over existing roof systems or layers of insulation on the roof deck, mechanical fastening can be used. Ensure to butt edges and stagger joints of adjacent panels. Go to www.certainteed.com for typical fastening patterns for field area of the roof. Refer to the current FM Loss Prevention Data Sheet 1-29 for increased attachment requirements for the perimeter and corners of the roof.

Adhesive Attachment - When installing a cover board over existing roof systems or layers of insulation on the roof deck, adhesive/bitumen attachment can be used. The recommended size for FlintBoard products for adhesive attachment is 4' x 4'. Ensure to butt edges and stagger joints of adjacent panels. Insulation must remain dry before, during, and after installation. When using hot-applied bitumen for attachment of insulation care must be taken to apply the bitumen at the correct temperature and in sufficient quantity to totally cover the insulation. To ensure embedment, the board shall also be “stepped in” at several points while the bitumen is still hot enough to allow positive attachment. When using polyurethane or cold applied asphaltic adhesives, follow the adhesive manufacturer’s installation recommendations or go to www.certainteed.com.

Storage/Precautions - Factory-applied packaging is intended only for protection during transit. When stored outdoors or on the job site, packages should be stacked on pallets at least three inches above ground level and completely covered with a weatherproof covering such as a tarpaulin. The temporary factory-applied packaging should be slit or removed to prevent accumulation of condensation. Roof insulation which has become wet or damaged should be removed and replaced with solid, dry insulation, of the same type.

Warning! Do Not Leave Exposed: This product is a polyiso organic plastic foam and will burn if exposed to an ignition source of sufficient heat and intensity, or open flame, such as a welder’s torch. Like other organic materials, this product will release smoke if ignited. Do not apply flame directly to FlintBoard roof insulations. This product should be used only in strict accordance with CertainTeed recommended uses and instructions.

Warranty Details

When used as part of a full assembly, product is covered under CertainTeed’s Integrity Roof System® NDL Limited Warranty.

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