Plymouth Foam

What is Plymouth Foam?

Plymouth Foam expanded polystyrene (EPS) insulation boards are foam plastic boards recognized for use as nonstructural thermal insulation sheathing.  The boards are intended for use in wall cavities, behind exterior wall coverings on exterior walls, and in roofing applications.  The insulation boards may also be directly exposed in attics and crawl spaces without a covering when install with all of the following conditions being met:


  1. Entry to the attic or crawl space is only to service utilities, and NO storage is permitted.
  2. There are no interconnected attic or crawl space areas.
  3. Air in the attic or crawl space is not circulated to other parts of the building.
  4. Attic ventilation is provided when required and under-floor ventilation is provided when required.
  5. The boards have a maximum nominal density of 1.0 pcf (16 kg/m3) and a maximum thickness of 4 inches (102 mm).
  6. Combustion air is provided in accordance with sections 701 and 703 of the 2006 International Mechanical code or section M1703.3 or M1703.4 of the IRC.



EPS Expanded Foam Features:

  • Multi-ply, high barrier facers protect EPS from plasticizers given off by PVC roofing membranes
  • Closed cell structure of EPS provides long-term thermal performance and moisture resistance
  • Expanded Foam is classified as a roofing protection board under UL 790 for any UL classified PVC membrane
  • Superior water absorption properties: 0.20% by volume (ASTM C272)
  • Available in a variety of thickness’ and compressive strengths
  • Available in 4’ x 8’ sections. Available thickness: 1/2″, 1″, 1 1/2″
  • 1/4″  thickness available in 48″ rolls

Plymouth Foam