BUILDING PRODUCT SUBSTITUTION GUIDANCE

The current shortage of products means builders are increasingly turning to alternatives. This can be potentially problematic and MBIE has recently released specific guidance on what products can be substituted for plasterboard

It has been well documented that Aotearoa New Zealand is currently facing a shortage of plasterboard and other commonly used building products. This is largely due to supply chain issues associated with the downstream effects of Covid-19 and elevated levels of demand. 

Consequently, there is an increased possibility that some building products specified as part of a building consent may need to be substituted with a similar or comparable product.

A first-principles approach

The Building Code sets the minimum performance requirements that all building work must meet. However, it does not prescribe which materials, building methods or products to use.

Designers and homeowners can choose the product that fits their requirements if they can provide evidence that it complies with the relevant performance requirements of the Building Code.

MBIE’s plasterboard-specific guidance

MBIE recently released the guidance document Product Substitution – plasterboard for building consent authorities (BCAs), designers, contractors and building owners to better support them in using building products that differ from those originally requested by owners and specified in building consent applications.

It outlines a pathway to product substitution and compliance for plasterboard and other wallboard products and is best read in conjunction with the more general Product substitution guidance published by MBIE in November 2021.

The guidance was developed in conjunction with BCAs with a view to managing the approval of plasterboard substitution in a more nationally consistent manner.

In addition, MBIE has published the step-by-step guide for plasterboard product substitution, showing the roles played by manufacturers, designers, building consent officers and builders.

Three-step approach

The plasterboard product substitution guidance lays out a three-step approach consistent with MBIE’s broader product substitution guidance:

• It encourages people to consider the legal context, particularly any additional obligations and compliance-related matters that might arise from a product substitution.
• It points to the broader implications of using a different product to that specified, including whether it is fit for the same purpose and still meets the owner’s needs.
• It talks people through how to implement changes to consent – or example, if substituting the product requires a minor variation or, for more-complex changes, it might trigger an amendment to the building consent.

In summary, it also:

• Outlines and encourages the use of the minor variation process for substituting plasterboard.
• Lists those products that can be substituted as a minor variation.
• Explains what should be considered when substituting plasterboard that has:
• Standard performance requirements when used as lining only.
• Additional performance requirements such as a substrate lining in areas subject to water splash in bathrooms and kitchens or as an element within a fire-protection system, a sound-rated system or a bracing system.
• Advises what can be done in the design stage to avoid the need for product substitution – the consideration of other products and construction methods.
• Provides an appendix of links to other product information that may be of use to show compliance with the building code.

All parties have a role to play

A designer or builder who wishes to substitute a building product should ensure that:

• The customer is informed about and has agreed to the substitution taking place.
• They provide adequate evidence so the BCA can be satisfied on reasonable grounds that the building work will continue to comply with the building code.
• They are on site to talk to the building control officer (or are available in the event that it is a remote inspection) about the proposed substitution and provide documentation if this is requested.

Failure to provide sufficient information may lead to delays in assessing variations or rejection of the application or require an amendment to the building consent to be applied for.

Try to avoid the need to substitute in the first place

Most designers will already be trying to avoid specifying products likely to need to be substituted at the construction phase.

As a reminder, designers should check on the availability of products in short supply and consider whether any of the following are more readily available and could be suitable alternatives:

• Other readily available plasterboard products.
• Non-plasterboard panel systems such as plywood.
• Alternative construction systems.

 

The Codewords article above is republished verbatim from Issue 109. As such, neither PlaceMakers or Under Construction magazine’s publishers take responsibility for the accuracy of the article or its corresponding questions. Reading this article and answering the questions meets Skills Maintenance requirements.