Skip to content
TRI-BUILT ISO II GRF Roof Insulation Board, 3 in. x 4 ft. x 8 ft.
Regular price $53.08Orders start at $399 — combine any items to reach the minimum. Learn more
TRI-BUILT ISO II GRF Roof Insulation Board, 3 in. x 4 ft. x 8 ft.
TRI-BUILT ISO II GRF is a 3 in. thick polyiso rigid roof insulation board in a 4 ft. x 8 ft. panel, covering 32 sq ft per piece. It provides a thick thermal layer for low-slope roofing assemblies under the membrane. Sold by the piece.
Key Features:
- Thick polyiso board: 3 in. thick ISO II GRF polyisocyanurate rigid roof insulation.
- 32 sq ft per piece: Full 4 ft. x 8 ft. panel size for efficient coverage of flat roofs.
- High build-up: Thicker single layer reduces the number of lifts needed to reach design R-value.
- Lightweight for its size: Weighs approximately 16.48 lb per piece.
- Low-slope use: Intended for low-slope roofing assemblies under the roof membrane.
- Layerable: Can be combined with other ISO thicknesses in staggered multi-layer assemblies.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | TRI-BUILT |
| Manufacturer model | AC2_PL_050 |
| Sell unit | 1 panel, 3 in. x 4 ft. x 8 ft. |
| Product line | ISO II GRF Roof Insulation |
| Dimensions | 4 ft. x 8 ft., 3 in. thick |
| Coverage per unit | 32 sq ft per panel |
| Thickness | 3 in. |
| Material | Polyisocyanurate (ISO) rigid foam roof insulation |
| Weight | 16.48 lb per piece |
| Intended use | Rigid thermal insulation for low-slope roofing assemblies |
Coverage & How Much You Need:
One 4 ft. x 8 ft. panel covers 32 sq ft at a single 3 in. layer. Divide the roof area by 32 to size the job, and use the same count per additional layer in a multi-layer build-up.
Fit and Compatibility:
Part of the TRI-BUILT ISO II GRF rigid roof insulation family; combine with thinner boards for taper or total-thickness builds. Fasteners, plates, adhesives and membrane are sold separately.
Frequently Asked Questions (FAQ):
Q: How much area does one panel cover?
A: Each 4 ft. x 8 ft. panel covers 32 sq ft at a 3 in. thickness.
Q: Why choose a 3 in. board instead of thinner ones?
A: A thicker board reaches a higher total R-value with fewer layers and fewer joints in the assembly.
Q: How is it installed?
A: Rigid ISO insulation is typically mechanically fastened or adhered per the roofing system manufacturer's specifications; attachment materials are sold separately.
Q: Can it be mixed with other thicknesses?
A: Yes, contractors commonly layer different ISO thicknesses in staggered courses to reach the required total thickness.
Q: What does one order include?
A: One 3 in. x 4 ft. x 8 ft. ISO II GRF insulation panel, sold as a single piece.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
At 3 in., this board suits assemblies needing substantial R-value with fewer lifts; check crane or hoist requirements for multi-layer jobs. Stagger the joints of each layer and inspect the boards for damage before installing. Always confirm the design thickness against local energy-code requirements.
Keep rigid polyiso boards away from open flame and heat sources, and follow all manufacturer and local-code requirements for roofing insulation installation.
Get TRI-BUILT ISO II GRF 3 in. roof insulation panels now for a thick, efficient thermal layer.
All third party trademarks, including logos and icons, referenced on our website and product pages remain the property of their respective owners. Unless specifically identified as such, Arbor's use of third party trademarks does not indicate any relationship, affiliation, sponsorship, or endorsement between Arbor Home and the owners of these trademarks. Any references by Arbor Home to third party trademarks are to identify the corresponding third party goods.
