Light steel framing

Also see:


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

MaterialRelevant standard
Mineral woolBS EN 13162
Flame retardant (FR) grade expanded polystyreneBS EN 13163
FR grade extruded polystyreneBS EN 13164
Rigid polyurethane foam and polyisocyanurateBS EN 13165
Phenolic foamBS EN 13166
Cellular glassBS EN 13167
Other insulation materialsTechnical 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.