Thermax White Finish Sheathing, 1.55 in, 4'x8' Sheet, R 10.1

DOW 280966
Product sold by bundle. To Order Call 888-223-3050
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THERMAX™ White Finish Sheathing is a nonstructural, rigid board insulation consisting of a glass-fiber-infused polyisocyanurate foam core laminated between an embossed white acrylic coated aluminum facer and a 1.0 mil, smooth, reflective aluminum facer on the oppisite side. The glass-fiber reinforcement contributes to improved fire performance and dimensional stability. THERMAX™ Sheathing can be installed exposed to the interior without a thermal barrier and offers high, long-term R-value. Used in conjunction with the appropriate joint closure system, THERMAX™ Sheathing with its low perm rating reduces moisture condensation within and behind the insulation. Thermax White Finish gives you a good looking washable finished surface with the added benefits of a closed cell insulating board.


  • Thickness: 1.55 inch
  • Sheet Size: 4' x 8'
  • R Value: 10.1
  • Surface Finish: White/Foil
  • 29 Pieces per Bundle
  • Minimum Order: 8 Bundles

Panels can be glued to most wall surfaces using Great Stuff Wall & Floor Adhesive or Great Stuff Enerfoam. Once Panels are fastened, use matching Thermax White Foil Tape to cover seams to give a finished look and reduce air infiltration.  For even better leak protection use Great Stuff Gaps & Cracks to fill between panels and seal openings.

Want to get adhesive foam and tape in one package. Take a look at our Thermax Installation Kit.

Additional Sizes

We stock additional sizes of Thermax. Follow the links for pricing and information.

White Finish: 1"x4'x8', 1.55"x4'x9' and 2"x4'x8'

Foil Sheathing: 1/2", 1", 1.55" and 2"

We can special order even more sizes. Please contact us for details.

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, and can be used in exterior walls. Because of its improved fire performance, THERMAX™ Sheathing is especially appropriate for hourly rated assemblies.
  • Approved for use, per Section 2603.5 of the International Building Code, in Exterior Walls of Types I,II,III and IV construction. THERMAX™ Sheathing is designed for use as continuous insulation in both interior and exterior applications to assist in meeting and exceeding both the most current IECC and the ASHRAE 90.1 energy standards. Maximum length is 30 ft. (9.1 m) and maximum thickness is 4.25" (108 mm).


Prices quoted are for delivery from factory. Minimum quantities and delivery charges may apply. Please contact us for delivery costs. Additional charges may apply if shipping to a residence, extended service area, or business that does not have a loading dock.

Questions? - Call us at 888-223-3050




1 Review

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  • 4
    Nice product.. Quick and easy to install

    Posted by Unknown on Mar 31st 2015

    Looks good if you don't feel like fully finishing out any concrete structure.. basement, garage. Surface is easily dented or gouged. Not ideal for hard use areas. Use 9 fasteners per sheet. Sheets can become cupped from factory and you will have an air gap behind them.