MBIE has re-released guidance on product substitution. The guidance provides key points to consider when thinking about using building products different from those originally requested and specified.
The Building Code sets out minimum performance requirements for buildings. These requirements can be met using a variety of different products, systems or both. In some cases, the products or systems may well exceed the minimum requirements of the Building Code. In other cases, they only meet the minimum requirements.
When deciding how to deal with a product substitution, the responsibility falls on the applicant to demonstrate that the proposed substitute will meet the performance requirements of the Building Code. Where the new product performs differently to the one specified, the applicant should also describe the effect of the change on other work.