This option uses relevant documentation to support an Alternative Method proposal. Documents may include:

• manufacturers’ technical literature
• test results for a system or product
• NZ Standards
• Ministry of Business, Innovation and Employment determinations
• BRANZ Appraisals and published information such as Good Practice Guides and bulletins
• overseas or New Zealand literature on building renovation
• historical documents such as catalogues of building components. 

The support documentation must be relevant to the project and from a reputable source. 

The BCA is not obliged to accept the performance claims from support documentation, so evidence should be selected that is relevant to the proposed design and specifically supports the Code requirements.

When to use this option

Comparison with other documents can be a useful tool where:

• historical information on a material’s performance or design at the time of construction (or modification) can be obtained
• new but similar materials are being proposed
• the proposed solution has been consented elsewhere
• existing building performance, for example, structural bracing, can be evaluated using an old version of a standard
• council records of a building’s construction are comprehensive.

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Providing evidence

Examples of supporting evidence could include:

• reference to BRANZ horizontal weatherboard weathertight solution details for bevel-back boards, which show window frame details that incorporate casement timber window frames
• original drawings where available
• comprehensive building survey reports including measured drawings
• drawings and details that have been prepared for a similar project.