Acceptable Solution B1/AS1 references NZS 3604:2011, the latest version of this Standard which replaced the 1999 version.
NZS 3604 is used to design most homes and other low-rise timber-framed buildings in New Zealand.
Standards New Zealand updated the Standard in 2011 to align it with the loadings Standard AS/NZS 1170, particularly with regard to wind, earthquake and snow loads.
The limited technical review of the Standard was also aimed at reflecting current construction practices, and simplifying and clarifying the document.
For example, new diagrams clarify how to determine loaded dimensions and spans, while durability requirements have been clarified by new tables and diagrams describing exposure conditions.
NZS 3604:2011 is also aligned with the revised Acceptable Solution for weathertightness for timber-framed buildings, E2/AS1.