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Atlas ACFoam-III Grade-III 25 psi Polyiso Roof Insulation 2.5 in x 4 ft x 8 ft
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Atlas ACFoam-III Grade-III 25 psi Polyiso Roof Insulation 2.5 in x 4 ft x 8 ft
Atlas ACFoam-III Grade-III polyisocyanurate roof insulation board is 2.5 in thick, 4 ft x 8 ft, rated at 25 psi compressive strength. One board covers 32 sq ft; the stated 608 sq ft corresponds to a 19-board unit. Sold per piece for low-slope roofing assemblies.
Key Features:
- 2.5 in Thickness: 2.5 inch polyiso board for high R-value per inch.
- 25 psi Strength: Grade-III 25 psi compressive strength for membrane roofing assemblies.
- 4x8 Board: Standard 4 ft x 8 ft board dimensions.
- FM Approved: FM Standard 4450/4470 approved.
- Miami-Dade & FL: Miami-Dade County Approved and Florida Product Approved.
- UL Classified: UL 1256, UL 790 (ASTM E108), UL 263 (ASTM E119) and UL 1897 listings.
- Greenguard: Greenguard certified for low chemical emissions.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | Atlas |
| Sell unit | 1 board (PC) |
| Product line | ACFoam-III |
| Dimensions | 2.5 in x 4 ft x 8 ft |
| Compressive strength | 25 psi (Grade-III) |
| Coverage per unit | 608 sq ft (stated unit coverage) |
| Material | Polyisocyanurate (polyiso) foam insulation |
| Approvals | ASTM C1289; CAN/ULC-S704; CCMC 12423-L; UL 1256, 790, 263, 1897; FM 4450/4470; Miami-Dade; Florida Product; Greenguard |
| Weight | 18 lb per piece |
| Intended use | Low-slope roof insulation in membrane roofing assemblies |
Coverage & How Much You Need:
A single 4 ft x 8 ft board covers 32 sq ft; the stated coverage of 608 sq ft corresponds to a 19-board unit. Divide total roof area by 32 sq ft to count boards, adding for taper or layered thickness requirements.
Fit and Compatibility:
Used as roof insulation under single-ply, modified bitumen or built-up roofing membranes with appropriate adhesives, fasteners and plates. Those components are sold separately.
Frequently Asked Questions (FAQ):
Q: What size is the board?
A: 2.5 in thick, 4 ft x 8 ft.
Q: What is the compressive strength?
A: 25 psi, Grade-III per the product title.
Q: How much area does it cover?
A: Each 4x8 board covers 32 sq ft; the item's stated coverage is 608 sq ft per unit.
Q: What standards does it meet?
A: ASTM C1289, UL listings 1256/790/263/1897, FM 4450/4470, Miami-Dade, Florida Product, and Greenguard certifications.
Q: How is it attached?
A: Follow your roofing membrane system's attachment method; adhesives and fasteners/plates are sold separately.
Q: How much does a board weigh?
A: Approximately 18 lb per piece.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
Polyiso is the go-to cover board/insulation for low-slope membrane roofs; 2.5 in at 25 psi suits membrane systems where moderate compressive load is expected. Confirm total R-value needs and layer 2.5 in boards over a lower layer if required. Check FM/Miami-Dade approvals against your project spec before substituting thickness.
Handle boards flat to avoid flex cracking, and follow roofing-system fire and hot-work safety rules during installation.
Order Atlas ACFoam-III 2.5 in polyiso roof insulation for your membrane roof.
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