About this document
This guide is a companion guide to Acceptable Solution E2/AS1 for Building Regulations clause E2 External Moisture. It can help designers, builders, councils and building owners understand potential weathertightness risks of a proposed design and options to either manage or reduce them.
Help in identifying individual building features that require particular care and attention in relation to external moisture during design and construction.
Councils will find the guide useful when determining weathertightness risks for building designs in terms of Acceptable Solution E2/AS1. It may also help them assess alternative building envelope designs for compliance with Building Regulations Clause E2 External Moisture. While many building materials are not included in E2/AS1, the principles of risk assessment can still be relevant.
This guidance explains the six risk factors of the risk matrix in more detail, and provides three worked examples for different building designs.