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GAF EnergyGuard Polyiso Insulation Board, 1 in. to 2 in. Thick, 4 ft x 8 ft Sheets, 20 PSI Polyisocyanurate Foam
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GAF EnergyGuard Polyiso Insulation Board, 1 in. to 2 in. Thick, 4 ft x 8 ft Sheets, 20 PSI Polyisocyanurate Foam
GAF EnergyGuard is a rigid polyisocyanurate foam insulation board for low-slope roofing, sold here in 1.0 in. and 1.75 in. 4 ft x 8 ft sheets and 2.0 in. sheets in 4 ft x 4 ft or 4 ft x 8 ft sizes, all rated 20 PSI. Each sell unit is one sheet. Stack layers to build up R-value under single-ply membranes or other roof coverings.
Key Features:
- High R-value core: Polyisocyanurate foam is one of the most thermally efficient rigid insulations commonly used on flat roofs.
- Multiple thicknesses: The line includes 1.0 in., 1.75 in. and 2.0 in. boards to reach the R-value your design requires.
- Two footprint sizes: Available in 4 ft x 8 ft sheets for broad coverage and 4 ft x 4 ft boards for easy handling and tighter roofs.
- 20 PSI compressive strength: The listed boards carry a 20 PSI rating for use beneath roof membranes.
- Whole-sheet units: Each variant sells as a single sheet in its stated size.
- Roofing-system pairing: Use under GAF or other compatible single-ply membrane systems with appropriate insulation attachments.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | GAF |
| Sell unit | 1 sheet |
| Product line | EnergyGuard |
| Available sizes | 1.0 in. x 4 ft x 8 ft; 1.75 in. x 4 ft x 8 ft; 2.0 in. x 4 ft x 4 ft; 2.0 in. x 4 ft x 8 ft |
| Material | Polyisocyanurate foam |
| Dimensions | Sheets of 4 ft x 8 ft or 4 ft x 4 ft, thicknesses 1.0 in. to 2.0 in. |
| Thickness | 1.0 in., 1.75 in., or 2.0 in. depending on variant |
| Compressive strength | 20 PSI (as listed on the board variants) |
| Coverage per unit | One 4 ft x 8 ft sheet covers 32 sq. ft.; one 4 ft x 4 ft sheet covers 16 sq. ft. |
| Intended use | Rigid roof insulation for low-slope roofing assemblies |
Coverage & How Much You Need:
A 4 ft x 8 ft sheet covers 32 sq. ft. and a 4 ft x 4 ft sheet covers 16 sq. ft. before allowances for joints or laps. Divide total roof area by the sheet coverage to estimate quantities, and layer multiple thicknesses where greater R-value is needed.
Fit and Compatibility:
Designed for use as rigid insulation under low-slope roof membranes, including GAF roofing systems; check the membrane manufacturer's requirements for attachment and acceptable substrates. Fasteners, adhesives, cover boards and membranes are sold separately.
Frequently Asked Questions (FAQ):
Q: What comes with an order?
A: One sheet of EnergyGuard polyiso insulation in the thickness and footprint you select.
Q: How many sheets do I need?
A: Divide your roof area by 32 sq. ft. for 4 ft x 8 ft sheets or 16 sq. ft. for 4 ft x 4 ft sheets, then add for waste and layout.
Q: What thickness should I choose?
A: Choose the thickness that meets the R-value target of your roof assembly; 1.0 in., 1.75 in. and 2.0 in. options are listed in this line.
Q: Can it hold foot traffic during installation?
A: The listed boards carry a 20 PSI compressive rating for use under roofing; still avoid point loads and follow the membrane manufacturer's installation guidance.
Q: Is it compatible with my membrane?
A: Polyiso boards are commonly used under single-ply and other low-slope membranes, but confirm attachment method and compatibility with your membrane manufacturer's specifications.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
EnergyGuard polyiso is the standard choice when you need maximum R-value per inch on a low-slope roof. Use 4 ft x 4 ft boards on small or obstructed roofs and 4 ft x 8 ft sheets for open fields to cut joint count. Where a heavier membrane or cover board is specified, verify fastener pull-out and density requirements for the chosen thickness.
Handle large sheets carefully in wind and wear gloves and eye protection when cutting polyiso, which can shed dust and splinters.
Order GAF EnergyGuard polyiso insulation boards in the thickness and sheet size your roofing project needs.
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