In this guide
2. Cavity wall
The installation of cavity wall insulation is specifically defined as notifiable building work in the Building Regulations. This means that for all buildings which are not exempted from the Regulations it will be necessary to submit a building notice to a building control body stating that cavity wall insulation work will be carried out. Most local authorities do not levy a building control charge in respect of such building notices. If the installer is registered with The Cavity Insulation Guarantee Agency the installer will in most cases submit the building notice. In any case building owners should always check that a building notice will be submitted.
The Building Regulations require that the insulation material used is suitable for the wall construction concerned. In the case of some foam cavity wall insulating materials an assessment of the risk of the emission of formaldehyde gas will need to be carried out.
Local authority building control departments can give more detailed guidance.