Skip to content
Carlisle SynTec InsulBase 2 in. x 4 ft x 8 ft Grade-II (20 psi) Polyiso Roof Insulation Board
Regular price $44.46Orders start at $399 — combine any items to reach the minimum. Learn more
Carlisle SynTec InsulBase 2 in. x 4 ft x 8 ft Grade-II (20 psi) Polyiso Roof Insulation Board
This is Carlisle SynTec InsulBase Grade-II polyisocyanurate roof insulation, a 2 in. thick, 4 ft x 8 ft board rated to 20 psi compressive strength. One board covers 32 sq ft of roof area and is sold per piece. Use it within a Carlisle SynTec commercial roofing assembly under approved single-ply membranes.
Key Features:
- 20 psi compressive strength: Grade-II polyiso board rated to 20 psi compressive strength for commercial roof assemblies.
- ASTM C1289 compliant: Manufactured to ASTM C1289, Type II, Class 1, Grade 2 polyiso classification.
- Code approvals: Approved under IBC Section 2603, Florida Building Code, California Title 24 and CAN/ULC S704 Type 2 & 3, Class 3.
- FM Class 1: FM Standards 4450/4470 Class 1 Approval and UL Classified (UL 790, UL 263, UL 1256).
- Full 32 sq ft board: Standard 4 ft x 8 ft sheet provides 32 sq ft of coverage with a 2 in. thickness.
- LEED supportive: PIMA Quality Mark Approved, CDPH compliant and recognized for LEED contributions.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | Carlisle SynTec |
| Sell unit | 1 board, 2 in. x 4 ft x 8 ft (32 sq ft) |
| Product line | InsulBase |
| Material | Polyisocyanurate (polyiso) foam insulation |
| Dimensions | 4 ft x 8 ft x 2 in. thick |
| Compressive strength | 20 psi (Grade II) |
| Coverage per unit | 32 sq ft per board |
| Thickness | 2 in. |
| Approvals | ASTM C1289 Type II Class 1 Grade 2; IBC Section 2603; UL 790; UL 263; UL 1256; FM Standards 4450/4470 Class 1 Approval; California Title 24; PIMA Quality Mark; CAN/ULC S704 Type 2 & 3 Class 3; Florida Building Code Approved; CDPH Compliant; UL Classified; LEED |
| Intended use | Commercial low-slope roof insulation under membrane roofing systems |
| Weight | 13.504 lb per board |
Coverage & How Much You Need:
Each 2 in. x 4 ft x 8 ft board covers 32 sq ft. Divide your total roof area in square feet by 32 to determine board count, then add boards for tapered or layered build-ups as specified by the roofing system design.
Fit and Compatibility:
InsulBase polyiso boards are used as insulation in Carlisle SynTec commercial roofing assemblies beneath membranes and cover boards. Fastening method, layers and cover board requirements should follow the roofing system specification; membranes, fasteners and plates are sold separately.
Frequently Asked Questions (FAQ):
Q: What is included in one order unit?
A: One 2 in. thick, 4 ft x 8 ft InsulBase Grade-II (20 psi) polyiso board, sold per piece.
Q: How much area does one board cover?
A: One board covers 32 sq ft; divide your roof area by 32 to calculate the number of boards needed.
Q: What compressive strength is this board?
A: It is a Grade-II board rated to 20 psi compressive strength under ASTM C1289 Type II, Class 1, Grade 2.
Q: What standards does it meet?
A: It meets ASTM C1289, IBC Section 2603, UL 790/263/1256, FM 4450/4470 Class 1, CAN/ULC S704, Florida Building Code and California Title 24, and carries the PIMA Quality Mark.
Q: How is the board installed?
A: Install per the roofing system manufacturer's specification, typically mechanically fastened or adhered in layers under the membrane and cover board; fasteners and plates are sold separately.
Q: How much does a board weigh?
A: Each 2 in. board weighs approximately 13.5 lb, making it easy to carry onto the roof.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
InsulBase Grade-II 20 psi polyiso is the workhorse board for standard commercial low-slope assemblies; specify higher grades only where heavy traffic or cover board loads demand it. Stack boards with staggered joints and install per the membrane system specification, adding a suitable cover board where the system calls for one. At 2 in. per layer, thickness is built up in multiple lifts to reduce thermal bridging at board joints.
Handle polyiso boards with care on the roof edge and secure loose boards against wind uplift before the membrane is installed.
Order Carlisle SynTec InsulBase 2 in. 20 psi polyiso roof insulation board for your commercial roofing project.
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.
