Flat polyisocyanurate board is a rigid foam insulation panel with facers bonded to both sides of a closed-cell foam core. It is the standard insulating layer in low-slope commercial roof assemblies and is also used as continuous insulation on walls where a high thermal resistance per inch of thickness is wanted.

"Flat" distinguishes this board from tapered polyiso, which is manufactured with a built-in slope to create drainage on a dead-level deck. Flat stock is used for the base layers, for fill, and anywhere a uniform thickness is required across the assembly. Boards can be mechanically fastened with plates and screws or set in adhesive, and multiple layers may be stacked with staggered joints to reduce thermal bridging at the seams.

Polyiso cuts cleanly with a utility knife or a fine-tooth saw, so field-fitting around curbs, drains and penetrations is straightforward. Panels should be kept dry and covered before the membrane or cladding goes on.

Key Features

• Rigid closed-cell polyisocyanurate foam core with facers bonded to both faces
• Flat, non-tapered profile for uniform thickness across the assembly
• High thermal resistance per inch compared with most other rigid board insulations
• Lightweight panels that a single worker can handle and carry on a roof
• Cuts with a utility knife or fine-tooth saw for fitting around penetrations
• Compatible with mechanically fastened or adhered attachment methods
• Can be installed in multiple layers with staggered joints

Applications

• Base and fill layers in low-slope commercial roof assemblies
• Insulation under single-ply, modified bitumen and built-up membranes
• Continuous exterior insulation on wall assemblies behind cladding
• Re-cover board over an existing roof during retrofit work
• Filling and leveling beneath tapered polyiso drainage packages
• Insulating flat decks, canopies and mechanical platforms

Product Details

• Type: Rigid foam board insulation
• Material: Polyisocyanurate (polyiso) foam
• Profile: Flat (non-tapered)
• Thickness: 2 in.
• Panel Size: 4 ft. x 8 ft.
• Sold As: Each

Specifications

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