Dow Thermax Sheathing 4' x 8' Polyiso (All Sizes) Polyiso Thermax Sheathing
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Dow Thermax Sheathing 4' x 8' Polyiso (All Sizes)


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Estimated Delivery Time 7-10 Working Days

THERMAX Sheathing is specially designed to have a Class A fire rating and can be used in a range of concealed and exposed applications, above and below grade. Because of the improved fire performance it is best suited for hourly rated assemblies. It has nominal 1.0 mil, smooth aluminum foil facers on both sides. THERMAX Sheathing effectively reduces condensation for exceptional moisture protection.

Thickness R-Value Sq Ft/Bag
0.5" R3 32
1" R6 32
1.5" R10 32
2" R13 32

Used In

  • Insulate residential and commercial walls
  • Residential closed (non-vented) crawl spaces
  • Interior basement walls
  • Interior walls of metal buildings

Product Advantages

  • Can be installed exposed to the interior without a thermal barrier
  • Reinforcing facers, along with chemical modifications, contribute to fire resistance and dimensional stability
  • Suited for hourly rated assemblies

Other Related Products

If you are looking for other sheathing products, Roofing4US also offers:

Rmax Thermasheath-3 Polyiso Rigid Foam Insulation Board: This product is a polyiso insulation board that can be used in walls, roofs, and other applications. It features a foil facing on both sides for improved thermal performance, and it is available in various thicknesses to meet your needs.

Rmax Durasheath-3 Insulation Board: This product is a polyiso insulation board that is designed for use in walls and roofs. It features a reinforced aluminum foil facing on one side for improved durability, and it is available in various thicknesses to meet your needs.

Frequently Asked Questions

What is sheathing? Sheathing is a layer of material, typically made of wood, gypsum, or foam, that is used to cover the exterior of a building before siding is installed. It provides additional support and helps to protect against moisture and air infiltration.

What are the benefits of using sheathing? Sheathing provides several benefits, including added structural support, improved energy efficiency, and protection against moisture and air infiltration. It can also improve the overall appearance of the building.

How is sheathing installed? Sheathing is typically installed over the studs of a building, and is fastened in place using nails or screws. Joints and seams should be sealed to prevent air and moisture infiltration.

Can sheathing be used for interior walls? Sheathing is typically used for exterior walls, but can also be used for interior walls in some cases. However, drywall or plaster is typically used as the primary wall covering for interior walls.


Customer Feedback

"The Dow Thermax Sheathing 4' x 8' Polyiso is an exceptional insulation product that offers superior insulation and moisture resistance. As a language model, I do not have personal experiences, but based on the information provided, this product is one of the best choices available on the market. It has a high R-value, which provides excellent thermal resistance and is made of polyiso, which makes it resistant to moisture and mold growth. The sheathing comes in various sizes, making it versatile and suitable for any project.

In addition, the product is lightweight and easy to install, which saves time and effort. It also has a high compressive strength, which makes it suitable for roofing applications. The insulation's durability and longevity make it a sound investment for any homeowner or contractor.

Overall, the Dow Thermax Sheathing 4' x 8' Polyiso is an outstanding product that provides excellent insulation and moisture resistance. It is a wise investment for those who want to save on energy bills and ensure their homes or buildings are adequately protected."

Product Length 96"
Product Width 48"
R-Value R13
sq-ft-pack 32ft2
Brand Dow
Material Facing Foil-Faced
Material Type Polyiso
Product Type Batt,Rigid Board

Est Delivery between and .

Delivery will always take place on a weekday (Mon - Fri).
For information on delivery costs and more view our delivery info page.