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ThermalStar® Flat Roof Insulation

Flat roof insulation is a vital component of a building’s envelope. For building designers requiring the highest quality rigid insulation, ThermalStar® Insulation Board provides unmatched quality, with a stable long-term R-value that will last the lifetime of your structure. ThermalStar Insulation Board is unfaced, flat roof insulation that is suitable for use with all roofing membrane materials and compatible with loose-laid and attached single-ply membranes.

Manufactured under an industry-leading quality control program monitored by UL and ICC-ES, ThermalStar Insulation Board meets or exceeds ASTM C578 standards, providing an HFC free, recyclable rigid insulation with a low Global Warming Potential (GWP).


  • Multiple thicknesses and compressive strengths
  • Design flexibility for custom roof profiles
  • Stable, long term R-value to protect your structure for years to come
  • Minimal long-term moisture retention with the ability to dry quickly
  • Environmentally friendly with a low global warming potential and zero ozone depletion potential
  • Limited lifetime warranty for physical and thermal performance