What is Expanded Polystyrene Bead?

This method of cavity wall insulation consists of pre-formed polystyrene beads, which are usually combined with a binding agent or adhesive, and then injected into the cavity space between the outer and inner masonary work.

Polystyrene beads are produced to a specified size and density which remains unaltered during the installation process. The installation must be carried out in accordance with the relevant BBA Certificate, their surveillance scheme, the System Suppliers installation Manual and all CIGA guides to best practice.

• The materials are produced under strict quality control to ensure compliance with the performance requirement of the appropriate British Board of Agrément (BBA) Certificate.
• The use of polystyrene bead for cavity wall insulation does not prejudice the fire resistance properties of the wall.
• The material is resistant to water penetration and will not transmit water across the cavity by capillary action or from below dpc level.
• The material is breathable and not a water vapour barrier, therefore it will aid the release of moisture through the wall.
• Once installed, the bead filling in the cavity will remain an effective insulant for the life of the building, and will require no further maintenance.

Installation Procedure

• A pre-installation assessment is carried out to determine the suitability of the property for cavity wall insulation. Internal and external checks are carried out by the Technician prior to installation.
• Injection holes are drilled in the external wall of the cavity as specified by the relevant BBA Certificate and System Suppliers manual.
• Typically holes are drilled around the upper part of the building only and below windows and lintels.
• The cavity at any party wall line is sealed with a closure approved by the BBA for the purpose.
• The polystyrene beads are injected into the cavity via an injection gun in a specified sequence to ensure a complete fill of the cavity.
• Following the installation the injection holes are made good to match the original wall surface as closely as possible.

Post Installation Checks

All fuel-burning appliances and their flues or source of air supply are checked to confirm their effectiveness

Further information and useful links

• Find a Insulation Installer near you
• Find a Builder near you

• National Insulation Association
• Energy Savings Trust (est.org.uk)
• Cavity Insulation Guarantee Agency (ciga.co.uk)
• Building Regulations an explanatory booklet (odpm.gov.uk)
• Party Wall Guidance (rics.org)
• Impact of the Party Wall Act 1996 (communities.gov.uk)