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Carlisle SynTec InsulBase 3.7 in. x 4 ft x 8 ft Polyiso Roof Insulation Panel, Grade II (20 psi)
Regular price $64.75Orders start at $399 — combine any items to reach the minimum. Learn more
Carlisle SynTec InsulBase 3.7 in. x 4 ft x 8 ft Polyiso Roof Insulation Panel, Grade II (20 psi)
This Carlisle SynTec InsulBase Grade-II panel is a 3.7 in. thick, 4 ft x 8 ft polyiso roof insulation board with a closed-cell foam core bonded to glass-reinforced felt (GRF) facers. Sold as a single panel covering 32 sq ft, it installs beneath Carlisle single-ply membranes on steel decks and other commercial roof assemblies.
Key Features:
- Maximum Thermal Value: InsulBase polyiso provides the highest R-value per inch of commercially available insulation products.
- ReadyFlash Technology: A dark GRF facer accelerates adhesive flash-off while the light GRF facer slows it down.
- Steel Deck Approved: Approved for direct application to steel decks.
- 20 psi Grade II: Meets ASTM C1289, Type II, Class 1, Grade 2 (20 psi compressive resistance).
- Code Approvals: UL Classified, FM Class 1 approved (4450/4470), Florida Building Code approved and IBC Section 2603 compliant.
- Low Environmental Impact: HFC- and HCFC-free formulation with zero ozone-depleting components.
- Sustainability Credits: CDPH compliant and contributes to LEED certification.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | Carlisle SynTec |
| Manufacturer model | 306088 |
| Sell unit | 1 panel, 4 ft x 8 ft x 3.7 in. |
| Product line | InsulBase |
| Material | Closed-cell polyisocyanurate foam with glass-reinforced felt (GRF) facers |
| Color | Tan |
| Dimensions | 4 ft x 8 ft, 3.7 in. thick |
| Thickness | 3.7 in. |
| Compressive strength | Grade 2 (20 psi) |
| Coverage per unit | 32 sq ft per panel |
| Standards | ASTM C1289, Type II, Class 1, Grade 2; IBC Section 2603; UL 790, 263, 1256; FM 4450/4470 Class 1; CAN/ULC S704 Type 2 & 3, Class 3 |
| Certifications | PIMA Quality Mark, CDPH compliant, LEED, Florida Building Code approved, California Title 24 |
| Weight | 22.336 lb per panel |
Coverage & How Much You Need:
Each 4 ft x 8 ft panel covers 32 square feet; divide roof area by 32 to estimate panel count.
Fit and Compatibility:
Use under Carlisle SynTec single-ply membrane systems with Carlisle adhesives, fasteners and cover boards (sold separately). Intended for low-slope commercial roof assemblies, including direct application to steel decks.
Frequently Asked Questions (FAQ):
Q: What is included with this purchase?
A: One 3.7 in. thick, 4 ft x 8 ft InsulBase Grade-II polyiso insulation panel.
Q: How many panels do I need?
A: Each panel covers 32 square feet, so divide your roof area by 32 and add for waste and layout.
Q: Which side should I apply membrane adhesive to?
A: The dark GRF facer speeds adhesive flash-off and the light facer slows it, so choose the side that matches ambient temperature conditions.
Q: Is this panel code approved?
A: It is UL Classified, FM Class 1 approved under Standards 4450/4470, Florida Building Code approved, and meets IBC Section 2603 and ASTM C1289 Type II, Class 1, Grade 2.
Q: Does this panel work on steel decks?
A: Yes, InsulBase polyiso is approved for direct application to steel decks.
Q: What is the compressive strength?
A: This is a Grade 2 panel with 20 psi minimum compressive resistance.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
The 3.7 in. thickness suits assemblies with high R-value targets where you want to minimize the number of boards in the roof system. Stage thicker panels flat and keep them dry, since edges can be damaged by forklifts and foot traffic on thin stock. Pair with a Carlisle cover board where the spec calls for one, and confirm attachment requirements for your membrane system per Carlisle's data sheets.
Rigid foam boards are slippery on sloped surfaces; secure panels promptly and follow the manufacturer's installation instructions and local code.
Order Carlisle SynTec InsulBase 3.7 in. polyiso insulation panels for maximum R-value in your roof assembly.
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