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PermaTherm Expanded Polystyrene (EPS) Foam Panel Insulation

Our expanded polystyrene (EPS) foam panel insulation is the “core” of each highly-efficient PermaTherm insulated panel system. More than simply a form of insulation, it is also an innovative building material that lends to the design and structural integrity of many building projects.

And PermaTherm’s rigid foam panel insulation is “not your typical EPS.” Since the 1950’s, PermaTherm EPS has been recognized as a superior, mainstream insulation material, and new applications with PermaTherm EPS have greatly increased in number over the last decade.

PermaTherm EPS foam panel insulation is ideal for most insulation specifications and is easily fabricated to meet specific design and dimensional requirements. Contact our team at

to learn more about our rigid foam insulation for panels, or check out the resources below:


Benefits of PermaTherm EPS Rigid Foam Panel Insulation

PermaTherm manufactures its EPS rigid foam panel insulation under strict proprietary protocols. Quality control is assured through our state-of-the-art expanding, molding and curing facility. The end result is an absolutely superior insulating core, with the following benefits:
  • Our EPS foam insulation for panels has excellent thermal resistance and long-lasting thermal conductivity values.
  • It’s lightweight, easily-shipped, stored, handled and installed on the job site.
  • PermaTherm uses only UL-approved raw materials – there are no exotic blowing agents or volatile chemicals that may react negatively with other materials.
  • Due to its design flexibility and versatility, it can be cut into sheets, slabs or any design requirement to meet specific building code standards.

Millions of linear feet of PermaTherm EPS rigid foam panel insulation remain in use and problem-free today for building owners, insulation contractors and refrigeration engineers. Specify PermaTherm as your choice – call us today at 877-650-4543 or fill out our quick contact form for more information about our structural insulated panels.




Type I


Type II

Type IX

Density, minimum lb/ft3 D 303 or
D 1622
0.90 1.15 1.35 1.80
Density Range lb/ft3   0.90 - 1.14 1.15-1.34 1.35-1.79 1.80-2.20
Thermal Conductivity- K Factor 25F°F C 177 or
C 518
0.23 0.22 0.21 0.20
40F     0.24 0.235 0.22 0.21
75F     0.26 0.255 0.24 0.23
Thermal resistance- R-Value @ 1 in. 25F hr.ft2.°F/BTU   4.35 4.54 4.76 5.00
40F 4.17 4.25 4.55 4.76
75F 3.85 3.92 4.17 4.35

Strength Properties

Compressive 10% Deformation lb/in2 D 1621 10-14 13-18 15-21 25-33
Flexural lb/in2 C 203 25-30 30-38 40-50 50-75
Tensile lb/in2 D 1623 16-20 17-21 18-22 23-27
Shear lb/in2 D 723 18-22 23-25 26-32 33-37
Shear Modulus lb/in2 --- 280-320 370-410 460-500 600-640
Modulus of Elasticity lb/in2 --- 180-220 250-310 320-360 460-500

Moisture Resistance

Water Vapor Transmission perm-in E 96 2.0-5.0 1.5-3.5 1.0-3.5 0.6-2.0
Water Absorption (vol.) % C 272 < 4.0 < 3.0 < 3.0 < 2.0
Capillarity --- --- none none none none
Coefficient of Thermal Expansion (in/in)/°F D 696 0.000035 0.000035 0.000035 0.000035
Maximum Service Temperature °F
Long-term Exposure     167 167 167 167
Intermittent Exposure     180 180 180 180
Oxygen Index % D 2863 24.0 24.0 24.0 24.0
Permatherm Surface Burning Characteristics (per UL Listings)  
Flame Spread for 1 lb/ft3 up to 2 inch Thickness   E 84 5      
Smoke Development for 1 lb/ft3 up to 2 inch Thickness     50      
Flame Spread for 2 lb/ft3 up to 5 inch Thickness   E 84       5
Smoke Development for 2 lb/ft3 up to 5 inch Thickness   E 84       160

*Flame Spread and Smoke Development recorded while the material remained in the original test position. Surface Burning Characteristics derived from ASTM E-84 are not intended to reflect hazards presented by this product under actual conditions. The manufacturer in no event assumes liability beyond the purchase price or replacement of material proven to be defective and reported in a timely fashion, but not longer than six (6) months after shipment. Only the senior executive of PermaTherm has the authority to alter or extend these conditions.

PermaTherm’s EPS foam panel insulation products were tested by Underwriters Laboratories, Inc. and meet the requirements of the Standard Mechanical Code and the International Mechanical Code.