DuPont™ Thermax™ Heavy Duty Foam Insulation

Commercial | Residential | Multifamily | Wall

Made for high durability in difficult conditions

As an insulation and interior finish system for walls and ceilings, Thermax™ Heavy Duty Insulation stands up to the elements with a fiberglass core and thermoset-coated aluminum facing.


DuPont™ Thermax™ Heavy Duty Foam Insulation

Thermax™ Heavy Duty Insulation is designed as an insulation and interior finish system for walls and ceilings in metal, wood post frame, and concrete or masonry buildings, as governed by building codes. Thermax™ Heavy Duty consists of a glass-fiber-reinforced polyisocyanurate foam core faced with nominal 4 mil embossed white thermoset-coated aluminum on one side and 1.25 mil embossed aluminum on the other. The tough 4 mil white embossed aluminum surface makes it a durable insulation/finish choice for use in moderate-impact areas, and it can be pressure washed up to 2,000 psi with a 15-degree or greater spray tip (at 3’ minimum distance). Thermax™ Heavy Duty also offers high, long-term thermal resistance, with facers that help prevent water and water vapor intrusion into the insulation foam allowing it to stabilize at a higher R-value. Used in conjunction with the appropriate joint closure system for the application, Thermax™ Heavy Duty – with its low perm rating – can help to reduce moisture condensation within and behind the insulation.


Features & benefits

Feature Benefit
Easy to cut, handle, and install
  • Easy to use
  • Moisture Resistant
  • Reduces the potential for condensation within the wall assembly

    Physical properties

    Method Unit Value
    Compressive Strength1 ASTM D1621 psi, min. 25
    Water Absorption ASTM C209 % by volume, max. 0.1
    Water Vapor Permeance ASTM E96 perm, max <0.03
    Maximum Use Temperature - °F 250
    Flexural Strength ASTM C203 psi, min. 55
    Light Reflectance, Visual Light Spectrophotometer - % 65

    1 Vertical compressive strength is measured at 10 percent deformation or at yield, whichever occurs first


    Available sizes


    Thickness (in.) R-Value Board Size (ft.) Edge Treatment
    0.625 4.1 4 x 8, 4 x 12 Square Edge
    1.0 6.5 4 x 8, 4 x 12 Square Edge
    1.55 10.1 4 x 8, 4 x 12 Shiplap
    2.0 13.0 4 x 8, 4 x 12 Shiplap