Please be advised the Government has amended the Building Regulations to prohibit the use of combustible materials in the external walls of buildings in England over 18 metres that contain at least one dwelling.
The Building (Amendment) Regulations 2018 includes a list of construction components that are exempt from the combustible materials ban, for example, ‘fixings’ and ‘thermal break materials. It states that the requirement does not apply to thermal break materials where the inclusion of the materials is necessary to meet the thermal bridging requirements of Part L of Schedule 1.
Please click on this link which will take you directly to the B4 regulations (This is from Approved Document B, vol 1. And vol 2 – see requirement B4. The below extract can be found on page 77 of the document