Skip to content
TRI-BUILT 1.5 in. x 4 ft. x 8 ft. Polyiso ISO Rigid Roof Insulation Board
Regular price $29.11Orders start at $399 — combine any items to reach the minimum. Learn more
TRI-BUILT 1.5 in. x 4 ft. x 8 ft. Polyiso ISO Rigid Roof Insulation Board
This TRI-BUILT ISO rigid roof insulation board is a 1.5 in. thick polyisocyanurate panel in a 4 ft. x 8 ft. sheet, sold as one piece. It adds a rigid insulation layer to low-slope roof assemblies and pairs with cover boards, adhesives and membrane systems in the same build-up.
Key Features:
- Rigid polyiso core: Polyisocyanurate rigid foam board for low-slope roof insulation.
- Full 4x8 sheet: Each board measures 4 ft. x 8 ft., giving 32 sq ft of coverage.
- Versatile 1.5 in. thickness: 1.5 in. thickness suits mid-layer lifts and standard insulation build-ups.
- Lightweight board: Weighs approximately 10 lb per board for easy handling and cutting.
- Flat, square edges: Rigid board format lays flat for clean, staggered joints between layers.
- Buy by the piece: Sold per piece so order quantities match your layout exactly.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | TRI-BUILT |
| Manufacturer model | TB-316703 |
| Sell unit | 1 board, 4 ft. x 8 ft. x 1.5 in. |
| Product line | TRI-BUILT ISO Rigid Roof Insulation |
| Material | Polyisocyanurate (polyiso) rigid foam |
| Nominal size | 4 ft. x 8 ft. |
| Thickness | 1.5 in. |
| Coverage per unit | 32 sq ft per board |
| Weight | 10.02 lb per board |
| Intended use | Rigid roof insulation for low-slope roofing assemblies |
Coverage & How Much You Need:
One board covers 32 sq ft of roof area. Estimate board count by dividing total area by 32 and allowing extra for cuts and perimeter fit.
Fit and Compatibility:
Used as rigid insulation in low-slope roof assemblies alongside TRI-BUILT and other system components such as cover boards, adhesives and membranes. Attachment must follow the roofing system manufacturer's specifications.
Frequently Asked Questions (FAQ):
Q: What comes in one order?
A: One 1.5 in. thick, 4 ft. x 8 ft. polyiso insulation board.
Q: How much does one board cover?
A: Each 4 ft. x 8 ft. board covers 32 sq ft before any cut waste.
Q: How is it attached?
A: Typically mechanically fastened or adhered per the roofing system manufacturer's instructions and local code.
Q: Can boards be layered?
A: Yes, multiple lifts are commonly installed with joints staggered between layers.
Q: How much does it weigh?
A: Approximately 10.02 lb per board.
Q: Can it be cut to fit?
A: Yes, score and cut with a utility knife or insulation saw on site.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
A 1.5 in. polyiso board is a workhorse mid-layer thickness for building up total insulation in multiple lifts. Keep boards dry and store flat until installed, and stagger board joints between layers to limit thermal bridging. Confirm fastener density and wind-uplift requirements with the membrane manufacturer before starting.
Wear gloves, eye protection and a dust mask when cutting rigid foam, and follow the roofing system manufacturer's installation instructions and local code.
Order TRI-BUILT 1.5 in. ISO rigid roof insulation boards for a straightforward mid-layer insulation lift.
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.
