PLEASE NOTE:
Since publication in 2019, section 11.1 has been updated. The update has been added at the end of this document.

 

The guidance in this document is concerned with the calculated U-values of new building elements, including walls, roofs, floors, windows and doors. Guidance is given on: thermal conductivity of materials (section 3); various issues that commonly arise when undertaking U-value calculations (section 4); various types of construction element, identifying which of the issues mentioned in section 4 apply to which construction type (sections 7 to 14). The document does not reproduce the details of the calculation methods, for which the reader is referred to the relevant British Standards and other sources (see References and further reading).

The 2002 edition of BR443 can be obtained here.

The 2006 edition of BR443 can be obtained here.