EPS Compared to XPS

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EPS Compared to XPS


There are market place misconceptions on the performance of EPS compared to XPS insulation. Consider these facts and make an educated decision.

Foam-Control EPS   XPS
ASTM C578 Standard Compliance.
Foam-Control EPS is manufactured in full compliance with ASTM C578, “Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation”.
ASTM C578 Standard Compliance.
XPS is usually manufactured in compliance with ASTM C578, “Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation”.
UL and ICC-ES Recognition.
Foam-Control EPS is recognized in UL ER11812-01 and ICC-ES ESR-1006 evaluation reports.
Limited Recognition.
Code reports for XPS are not available from UL. Some, but not all manufacturers have ICC-ES reports.
Closed Cell Polystyrene Foam Filled with Air.
Foam-Control EPS is a closed cell foam. It is manufactured from expanded polystyrene resin which is molded into blocks. Foam-Control EPS contains air within the closed cells.
Closed Cell Polystyrene Foam Filled with an Unknown Gas.
XPS insulation is a closed cell foam. It is manufactured from polystyrene, blowing agents, and dyes which are extruded into boards. XPS insulation contain gases other than air within the closed cells.
R-value: Stable Long-Term.
Foam-Control EPS is stable and the R-value will not change with time. Foam-Control EPS comes with a warranty for 100% of its original R-value.
R-value: Loses R-value over Time.
XPS is not stable and the R-value will drop over time as the cell gases escape. Since XPS loses R-value over time, the warranty for XPS is often only 90% of its original R-value.
Excellent Water Resistance.
Foam-Control EPS is a closed cell polystyrene foam which is naturally water resistant. Don’t be fooled by comparisons using short term laboratory test which are conducted for only 24 hours. Foam-Control EPS has been demonstrated to have lower water absorption than XPS in a number of long-term exterior exposure studies.
Excellent Water Resistance.
XPS is a closed cell polystyrene foam which is naturally water resistant. The water resistance of XPS is published for exposure to water in a laboratory after only 24 hours. Short term laboratory results do not correlate to long-term performance of XPS in exterior exposure conditions.
R-value: Water Exposure.
Insulations lose R-value when exposed to moisture. Long-term in-situ testing has shown Foam-Control EPS maintains a servicable R-value.
R-value: Water Exposure.
Insulations lose R-value when exposed to moisture. Long-term in-situ testing has shown XPS will trap water which enters the cells and lower its R-value.
Vapor Permeance.
The vapor permeability of Foam-Control EPS ranges from 2.5 to 5.0 perms for a 1 in. thick material. This is approximately 2-3 times better than XPS.
Vapor Permeance.
The vapor permeability of XPS is typically 1.5 perms for a 1 in. thick material. XPS over 1.5 in. thick will act as a vapor retarder which may trap moisture is some climate zones.
A Great Value.
When purchasing insulation materials, the cost per R-value and strength are critical benchmarks. Foam-Control EPS is available in seven different Types which comply with ASTM C578. Products with compressive strengths of 10, 13, 15, 25, 40, and 60 psi are available. The wide range of Foam-Control EPS Types makes selecting the best product for your application easy. The cost per R-value for Foam-Control EPS is much less than XPS.
Expensive.
XPS is available in a limited number of Types which comply with ASTM C578. The most common product has a compressive resistance of 25 psi. Although XPS has a slightly higher R-value, the cost per R-value is much higher making XPS a more expensive insulation. In addition, the R-value is not fully warranted nor stable for the life of the product.
Don’t Compromise, EPS insulation provides more thermal resistance (R-value) per dollar.

Selecting Comparable EPS and XPS Insulations

  Foam-Control EPS Compared to XPS