Updates to Approved Document B

The government has recently published an update to Approved Document B to introduce new rules for external walls and balconies for newbuild blocks of flats between 11 metres and 18 metres in height.

Lower risk developments between 11-18 metres will need to meet the necessary safety standards, with the intention of allowing designers and developers flexibility to use environmentally friendly materials, such as structural timber as part of a robust system.

The latest changes to Approved Document B, builds on the changes already introduced to improve building safety, following the Grenfell Tower tragedy, with an emphasis on the fire performance of the external surfaces.

With the new update, residential buildings and Relevant buildings ‘as defined in regulation 7 (4)’ must use materials with a reaction to fire performance of A2 s1 d0 or better for the external walls, no matter what distance from a relevant boundary.

For buildings less than 11 metres in height, the reaction to fire performance must be B s3 d2 or better, if within 1000mm of a relevant boundary; however, there is no provision required if the relevant boundary is greater than 1000mm.