Expanded Polystyrene (EPS)

eps insulation, polystyrene insulation block boardsEPS is a widely used insulation material, known for its flexibility and thermal performance.  The boards are able to receive a variety of flat roof waterproofing systems, and can be easily cut to many shapes, sizes and falls as required.

Expanded Polystyrene (EPS)



Suitable for use under EPDM/ butyl rubber roofing and some single layer membranes.


Expanded polystyrene is a rigid cellular plastic, providing a versatile, moisture resistant thermal insulation solution.

Thermal performance

The thermal conductivity (lambda/λ-value) of EPS  is 0.034 – 0.038 W/m.K, dependent on grade.


EPS can be supplied in a multitude of dimensions and thicknesses.

EPS insulation is a popular choice due to it’s flexibility and benefits from:


  • Good thermal performance
  • Boards are lightweight, non-toxic and inert
  • Moisture resistant due to the boards closed cell structure
  • Huge flexibility for standard roofs or problematic roofs
  • Boards can be cut to any shape, thickness or tapered fall
  • Factory pre-mitred hips and valleys help aid water drainage to outlets
  • Easily accepts waterproofing systems
  • Green guide A+ rating

Ideal for use within Building Innovation’s Hybrid Systems


Contact us for detailed technical information.