As construction costs in New Zealand rise, Design for Manufacture and Assembly (DfMA) methods are becoming more financially viable, leading developers behind several recent residential and hotel developments to choose building with components manufactured locally or overseas.

At Peddle Thorp, for example, we are currently in the process of designing, documenting and delivering 252 residential units and 242 hotel rooms across both modular and volumetric systems.

Despite its increasing popularity, currently there is no set consenting process for DfMA materials in New Zealand. An unintended consequence of this situation is that developers and builders are devising their own pathways towards obtaining consents—with varying degrees of success.

Recently, we were working with a client building prefabricated hotel rooms, with the rooms built in a factory near Wellington then transported to their Auckland destination site. For this project, multiple Building Consent Authorities (BCAs) – usually councils – requested several documentation packages: consents were required for the prefabricated building elements being prepared near Wellington, and separate consents were required for the Auckland building site where those same prefabricated units were finally situated.

The duplication of Building Consent packages caused unnecessary additional paperwork, delay and costs to the process.

Following this experience, the DfMA builder decided against pursuing this strategy further and instead, for future projects, will work with only one consenting authority and fly its consenting officials to the DfMA building site to be assessed.

In this example, it would have meant Auckland Council representatives were flown to Wellington to give consent for the building at one point in its development, and then, back in Auckland, give another consent for the building in its finished form. This would mean a frustrating load of paperwork and travel for the council representatives, with extra cost to the project.

We have also been made aware that due to the lack of clarity around DfMA consenting protocols, council representatives from New Zealand have been flown to Vietnam and China to give consent to pre-fabricated rooms and other materials before they enter New Zealand. This is obviously an expensive and time-intensive process, which further undermines the inherent benefits of the DfMA delivery model for all involved. 

The good news is public agencies and the private sector are looking into developing a formal certification regime for prefabrication factories across New Zealand and overseas so the process of consents will be made more linear.

The Ministry of Business, Innovation and Employment (MBIE), the government agency responsible for building regulations, is currently exploring ways for DfMA companies to be pre-certified in a similar fashion to CodeMark, a product certification scheme that provides an easily-understood way to show a building product meets the requirements of the New Zealand Building Code.

BCAs are required to accept a CodeMark certificate as evidence of compliance with the Building Code. If MBIE were to follow the same system with the certification of prefabricated materials, the fabricators would need to gain certification then maintain standards, and MBIE would monitor adherence to those standards over time. The proposed certification of DfMA manufacturing plants has been conceived to accelerate building code compliance assessment through establishing clear compliance pathways, which would improve the quality of the final product as it is manufactured in a controlled environment

For councils, this would mean revising certain existing consenting structures in favour of concentrating on monitoring and auditing manufacturers. Auckland Council is already setting up a qualified suppliers programme for Housing New Zealand to facilitate and speed up processing time frames. The lack of accommodation options in New Zealand gives urgency to these proposed changes, and as the lead consultant on multiple affordable housing developments, we welcome their implementation.

The benefits of a consenting certification process would include greater certainty around quality outcomes and better time and cost management; it would allow us to reduce expenses and bring more efficiency to projects.  In the end, that benefits everyone: our clients, councils and architects.

Update – 14 October 2019: Radio New Zealand reported on 11 October that Building and Construction Minister Jenny Salesa has announced a new streamlined process for prefabricated consenting, eliminating the need for two separate consents. Read more…

Click here to read Architecture New Zealand editor Chris Barton’s exploration of the current state of prefabrication in New Zealand.