Skip to content
GenFlex GL ISO Tapered Polyisocyanurate Insulation Board, 4' x 4', Multiple Tapers
Regular price $75.00Orders start at $399 — combine any items to reach the minimum. Learn more
GenFlex GL ISO Tapered Polyisocyanurate Insulation Board, 4' x 4', Multiple Tapers
GenFlex GL ISO Tapered is a 4 ft. x 4 ft. polyisocyanurate insulation board with a foam core bonded to fiber-reinforced facers, offered in taper packages from 0.5 in. to 3 in. total thickness. One sell unit is a single board. It suits virtually all membrane roofing systems, new construction and reroofing over most deck types.
Key Features:
- High cold-temp R-value: Delivers the highest R-value per inch in colder temperatures, potentially saving thousands in HVAC costs.
- Cold-weather performance: Up to 40% better thermal performance in cold temperatures than the competition.
- Patented formulation: A patented formulation provides superior thermal performance at low temperatures and improves the EPDs of the polyiso.
- Fiber-reinforced facers: Polyisocyanurate foam core is bonded to fiber-reinforced facers for handling strength.
- Broad deck approval: Approved for new construction and reroofing over virtually all roof deck types.
- Direct-to-deck suited: Especially suited for FM Approved and UL Classified direct-to-deck applications without an additional thermal barrier in most installations.
- Taper options: Offered in taper packages AA, X, Q, A, B, Y, C and D ranging from 0.5 in. to 3 in.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | GenFlex |
| Sell unit | 1 board, 4 ft. x 4 ft. |
| Product line | GenFlex GL ISO insulation |
| Available colors | Gray |
| Available sizes | 4' x 4' boards in taper packages: (AA) 0.5"-1", (X) 0.5"-1.5", (Q) 0.5"-2.5", (A) 1"-1.5", (B) 1.5"-2", (Y) 1.5"-2.5", (C) 2"-2.5", (D) 2.5"-3" |
| Dimensions | 4 ft. x 4 ft. board |
| Material | Polyisocyanurate foam core with fiber-reinforced facers |
| Thickness | Varies by taper package, 0.5 in. to 3 in. total |
| Intended use | Tapered thermal insulation for membrane roof systems, new construction and reroofing |
| Approvals | Especially suited for FM Approved and UL Classified direct-to-deck applications/assemblies without an additional thermal barrier in most installations |
Coverage & How Much You Need:
Each 4 ft. x 4 ft. board covers 16 sq. ft. of roof area. Divide your roof area by 16 sq. ft. per board and add waste; the selected taper package sets the slope over the run.
Fit and Compatibility:
Designed for use with virtually all membrane roofing systems, including GenFlex membrane assemblies, and for direct-to-deck applications as described. Membrane, fasteners and plates are sold separately.
Frequently Asked Questions (FAQ):
Q: What size is each board?
A: Each board is 4 ft. x 4 ft., covering 16 sq. ft., with thickness depending on the taper package you choose.
Q: Which taper package do I need?
A: Taper packages range from (AA) 0.5-1 in. up to (D) 2.5-3 in.; your roof design's slope and drain layout determine the package, so follow the tapered insulation layout.
Q: Can it go directly on the deck?
A: Yes, it is especially suited for FM Approved and UL Classified direct-to-deck applications without an additional thermal barrier in most installations.
Q: Does it work in cold climates?
A: Yes, GenFlex polyiso provides the highest R-value per inch in colder temperatures and up to 40% better cold-temperature thermal performance than the competition.
Q: Is it for new roofs and re-roofs?
A: It is approved for new construction and reroofing over virtually all roof deck types.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
Choose the taper package from your roof drainage layout: steeper packages like (C) and (D) move water faster over long runs, while (AA) and (X) suit shallow crickets and short spans. Store boards flat and dry, and keep layout drawings handy so boards are placed in sequence. Pair with a compatible GenFlex membrane and proper fastening for the assembly rating you need.
Follow the roof assembly's fire and fastening requirements and local codes when installing insulation directly to the deck.
Order GenFlex GL ISO Tapered insulation boards today to build slope and R-value into your membrane roof.
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.
