External Wall Insulation EPS

In stock
Regular price £59.76

Expanded polystyrene EPS insulation board Data Sheet

Expanded polystyrene EPS insulation board is a high-performing thermal insulation at the centre of our external wall insulation systems. It significantly upgrades the thermal properties of a building, improving U-values, and reducing the risk of water penetration and condensation. EPS boards are compatible with timber, masonry and system-built properties, as well as tile hanging and a wide range of rendering systems. EPS has been designed specifically to be applied onto masonry or timber-backed walls using adhesive and mechanical fixings. They can also be installed in the cavity void if the property is being insulated using cavity wall insulation.

EPS insulation is the most popular material used in external wall insulation systems. One of the stand-out benefits of using EPS for your project is that it’s great value for money. In this way, choosing a cost-effective insulation board means that you can cut down on cost without sacrificing quality or thermal performance.


Technical Specification

  • Composition: expanded polystyrene, graphite
  • Thermal Conductivity: 0.032W/(m2K)
  • Reaction to Fire: Class E
  • Compressive strength: 70kPa
  • R-value: 1.97W/(m2K)
  • Weight: 13.02kg
  • Weight/m2: 1.13kg
  • Size of boards: 1200 x 600mm
  • Thicknesses available: 50mm, 70mm, 90mm & 100mm
  • Coverage in pack: 0.72m2
  • Bending strength: >= 75kPa


Use netting on scaffolding to reduce the amount of polystyrene blowing about in the wind. We highly recommend that you try to use a hot knife or hot wire cutters to minimise the number of polystyrene offcuts. However, you can still use a standard knife should you choose. Ideally, you should cut the EPS insulation boards within a covered area as this reduces offcuts blowing around.

EPS Insulation Application

EPS insulation boards should always be installed in accordance with the manufacturer’s installation guidelines. This should cover design and all aspects of the application of the insulation. Initially, you can fix the EPS boards to the substrate (masonry or timber) by a mortar/adhesive or simply by mechanical fixings.

After fixing the board to an external wall, we recommend that you cover the boards with an outer layer. This can be either be the mortar basecoat or simply a netting covering to protect from excessive heat, moisture and UV exposure.

Before you apply the basecoat or mortar for the fibreglass mesh, you should rasp or sand down the top surface of the board to produce an abrasive surface. Once you’ve done this, the substrate is ready for the application of the fibreglass mesh. For further information, please download the full installation guide.