Also see:
BRE Report ‘Thermal insulation:avoiding risks’
6.10.17 Insulation
Insulation shall be correctly installed, be of a suitable material and thickness to comply with Building Regulations and reduce the risk of interstitial condensation.
Insulation should:
- be inert, durable, rot and vermin proof and should not be adversely affected by moisture or vapour
- cover the whole external face of the wall and be complete within the frame
- extend 150mm below the base rail to minimise thermal bridging and maintain a warm frame
- be tightly butted with joints of rigid board insulation, taped where required by the design.
Foil-faced insulation boards with an integral facing on one side only should be fixed with the foil face on the cavity side.
Table 9: Acceptable insulation materials
| Material | Relevant standard |
|---|---|
| Mineral wool | BS EN 13162 |
| Flame retardant (FR) grade expanded polystyrene | BS EN 13163 |
| FR grade extruded polystyrene | BS EN 13164 |
| Rigid polyurethane foam and polyisocyanurate | BS EN 13165 |
| Phenolic foam | BS EN 13166 |
| Cellular glass | BS EN 13167 |
| Other insulation materials | Technical Requirement R3 |
Account should be taken of Accredited Construction Details where applicable.
Reference should be made to BRE document BR 135 ‘Fire performance of external thermal insulation for walls of multi-storey buildings’ when specifying the type of insulation system to be installed.
Last updated: 2nd January 2024