TRI-BUILT 1 in. x 4 ft. x 8 ft. ISO II GRF Polyiso Roof Insulation Board

This TRI-BUILT ISO II GRF roof insulation board is a 1-inch-thick, 4 ft. x 8 ft. polyisocyanurate panel for low-slope roof assemblies, ideal as a base layer or thin lift. One board covers 32 sq ft and is sold per piece.

Key Features:

• 1 in. thickness: One-inch panel suits base layers or thin insulation lifts.
• 4 ft. x 8 ft. board: Standard 32 sq ft board for efficient coverage.
• GRF facer: Glass-reinforced facer in the ISO II line.
• Polyiso core: Polyisocyanurate foam insulation for low-slope roofing.
• Light handling: Approximately 7.84 lb per board for easy job-site handling.

Specifications Table:

Coverage & How Much You Need:

Each 1 in. x 4 ft. x 8 ft. board covers 32 sq ft. Divide the roof area by 32 and allow for cuts and waste; boards are also counted by the square (100 sq ft).

Fit and Compatibility:

Used in low-slope roof assemblies beneath approved membranes, often layered with thicker ISO boards. Attachment plates and adhesives are sold separately; install per the membrane manufacturer’s requirements.

Frequently Asked Questions (FAQ):

Q: What size is each board?
A: Each board is 4 ft. x 8 ft. and 1 inch thick, covering 32 sq ft.

Q: How many boards do I need?
A: Divide the roof area by 32 sq ft per board and allow for waste.

Q: What is GRF?
A: GRF refers to the glass-reinforced facer on this ISO II board.

Q: How much does a board weigh?
A: Approximately 7.84 lb per 1-inch board.

Q: Can it be layered with thicker boards?
A: Yes, thinner boards are commonly used as base or intermediate layers in multi-layer assemblies.

Expert Verdict Reviewed by the SuperArbor Pro Desk

Thin polyiso lifts are commonly used as base layers under thicker boards in staggered-joint, multi-layer assemblies to reduce thermal bridging. Verify attachment method and layer order with the membrane manufacturer and local code. Confirm the project’s total R-value needs before selecting thickness.

Store boards flat and dry and secure them against wind on the rooftop.

Order the TRI-BUILT 1 in. ISO II GRF polyiso roof insulation board for your next low-slope roofing job.