THERMAX™ Light Duty Insulation

THERMAX™ Heavy Duty Insulation has a glass-fiber reinforced polyisocyanurate foam core faced with 4.0 mil embossed white thermoset-coated aluminum on one side and 1.25 mil embossed aluminum on the other side. The surface makes it a durable choice for use in moderate-impact areas.

THERMAX™ Heavy Duty Insulation can be installed exposed to the interior without a thermal barrier and can be pressure-washed up to 2,000 psi with a 15-degree or greater spray tip (at minimum 3' distance). THERMAX™ Heavy Duty is designed as an insulation and interior finish system for walls and ceilings in metal, wood post frame and concrete or masonry buildings.

For best results, seal joints with tapes or joint closures from Dow.

Building Code Compliance

Complies with ASTM C1289 Type I, Class 2. Meets IBC/IRC requirements for foam plastic insulation. See ICC-ES ESR-1659. FM 4880 - see Factory Mutual Approval Guide. UL Classified, see Classification Certificate 1256. Calif. Std. Reg. # CA T383.

Related Information

Dow Polyisocyanurate Insulation 15-Year Limited Thermal Warranty (95KB PDF)
Joint Closure Systems for Enhanced Protection Against Air and Moisture Product/Installation Information (146KB PDF)
THERMAX™ Advantages Exposed – Sell Sheet (253KB PDF)
THERMAX™ Insulation Exposed Interior Wall Applications in Metal Buildings with Low Humidity (366KB PDF)
THERMAX™ Heavy Duty Insulation Product Information (Commercial) (85KB PDF)
THERMAX™ Heavy Duty Insulation Product Information (Residential) (53KB PDF)
THERMAX™ Metal Building Guide Specification (460KB PDF)

THERMAX™ Heavy Duty Insulation has a high-performance foam core faced with embossed white thermoset-coated aluminum on one side and embossed aluminum on the other side, making it an excellent choice for use in moderate-impact areas.

Nominal Board Thickness(1), in R-Value(2)(3) Board Size, ft Edge Treatment Min Compressive Strength(4), psi
.50 3.3 4 x 8 / 4 x 10 Square Edge 25
.75 5.0 4 x 8 / 4 x 10 Square Edge 25
1.0 6.5 4 x 8 / 4 x 10 Square Edge 25
1.5 9.8 4 x 8 / 4 x 10 Square Edge/Shiplap 25
2.0 13.0 4 x 8 / 4 x 10 Square Edge/Shiplap 25

(1) Not all product sizes are available in all regions.

(2) R means resistance to heat flow. The higher the R-value, the greater the insulating power. R-values are expressed in ft2• h•°F/Btu. R-value determined by ASTM C518.

(3) Consult your Dow Seller or Technical service Rep for information on different R-values

(4) Vertical compressive strength is measured at 10% deformation or yield, whichever occurs first. Since Dow polyisocyanurate insulation is a visco-elastic material, adequate design safety factors should be used to prevent long-term creep. For static loads, 3:1 is suggested. For dynamic loads, 5:1 is suggested.

03 47 13 – Tilt-up Concrete Insulation
07 20 00 – Board Insulation
07 21 13 – Board Insulation

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