Single Hazard Class for Timber Framing

21 September 2010

Following discussions that have taken place over the last year and a half and the conduct of boron leaching trials by BRANZ, the Minister of Building and Construction has now released a consultation document on proposals for a single hazard class for framing timber inside the building envelope.

Essentially the proposal is to adopt H1.2 as the single hazard class for framing timber inside the building envelope except for the critical performance of cantilevered deck joists which would need to be H3.2.

The proposed regime is designed to deal with perceived issues including the complexity of treatment and grade options in timber framing, the potential for errors in the use of framing timbers and the over specification of treatment hazard classes.

Sight has not however been lost of the ability for consumers to choose the level of treatment or preservative they prefer. In other words while H1.2 is regarded as the appropriate hazard class, there is nothing to prevent the use of timber of a higher hazard class being used.

The consultation document can be downloaded at .
Submissions are open until 29 October 2010 and can be made online through .

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