This website provides informational resources intended to assist the foam plastic insulating sheathing (FPIS) industry. We are committed to using sound science to develop research supporting the reliable, efficient, and economic design and installation of foam sheathing.

Originally presented as a webinar for CSI Chicago in June 2021, the video below captures a real-time tour of the valuable tools and resources you'll find on this website regarding the use of foam plastic insulating sheathing (FPIS) continuous insulation (ci). 

This video covers a lot of ground. Features of this presentation include the following topics, which can be accessed directly using these links:

What Is FPIS?

  • Foam plastic insulating sheathing (FPIS) is also known as rigid foam board or simply "foam sheathing."
  • It is available in three types: 
    • Expanded Polystyrene (EPS) - ASTM C578
    • Extruded Polystyrene (XPS) - ASTM C578 
    • Polyisocyanurate (Polyiso) - ASTM C1289
FPIS product types
  • It is a durable and versatile insulation material that is commonly installed as continuous insulation, which is more effective than cavity insulation because it is not thermally bridged by framing members (see Thermal Bridging Prevention). 
  • It has various applications including thermal insulation, water-resistive barrier, air barrier, and water vapor control depending on how it is designed and integrated into a building assembly.
  • FPIS R-values typically range from just under R-4/inch to more than R-6/inch It comes in thicknesses typically ranging from ½-inches to 3-inches or more.
  • It can be placed as a single layer or as multiple layers with joints typically staggered.
    • For example, 4-inch thickness is often achieved by two layers of 2-inch-thick FPIS

Applications  Benefits  FAQs is owned and operated by Applied Building Technology Group. The American Chemistry Council's Foam Sheathing Committee (FSC) has provided financial support. A list of FSC member companies is available here 

While every effort has been made to ensure the accuracy of the information presented on this website, its actual design, suitability and use in any particular application is the responsibility of the user. Where used in the design of buildings, the design, suitability and use of information on this website for any particular building is the responsibility of the Owner or the Owner's authorized agent, and the information used shall be submitted to the Building Official and reviewed for code compliance.

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