Important changes to our 10-year Master Build Multi-Unit Guarantee

9 December 2022

We just to remind you of the important changes to our 10-year Master Build Multi-Unit Guarantee. We are less than a month out from the new set of design criteria for developments over 11 units coming into place from 1 January 2023.

We want to confirm the changes and what they mean for members to ensure you are fully across the update.

Why is the update needed?

More multi-unit homes are now being consented than standalone houses, and we are also seeing growing demand for the Master Build Multi-Unit Guarantee to cover these projects. We support these developments, and we also recognise that they have their own unique risks that differ to typical residential building projects. To address this we have updated the Master Build Multi-Unit Guarantee to manage the higher risks that come with these large scale developments and ensure that quality is included at every stage of the build process.

What is changing?

We have updated the 10-year Master Build Multi-Unit Guarantee to streamline and clarify the application process and criteria. As with all our Guarantees this includes ensuring the builder is in a strong financial position, with a good history of similar developments. We will also assess the plans for the development to ensure they are sound and do not include any high-risk elements, particularly concerning weathertightness. We have also engaged an independent building consultant, Maynard Marks, to review and assess each application. This process provides an additional level of rigor and risk management for your development and will be a strong selling point for homebuyers.  

What does the updated design criteria cover?

The updated design criteria have a strong focus on eliminating weathertightness risk and  plans for each development will be reviewed by an independent expert. We have developed our criteria around elements that must be present, those that are prohibited, and those that should be kept to a minimum. This criterion will be a strong selling point for multi-unit homeowners. 

‘Must-have’ elements in the design includes cavity systems and rigid air barriers. There also needs to be a pitched metal roof (at more than 5%, and not curved), eaves, and gutters that are designed so that blocks and overflows can be visually identified. 

Other elements will also be assessed such as parapet walls, internal gutters, decks, complex junctions and multiple cladding types.

What do I need to do?

Ensure you are ready as the new criteria comes into place from 1 January 2023. Properties that already have a Master Build 10-year Guarantee will continue to have cover. 

You will apply for a Guarantee as you always have, via Ruanuku through Offsite. Your application will be reviewed by our Guarantees team, and the design of the development will be assessed by an independent building consultant. We will notify you for more information if needed or to update you on the process within 14 days of receiving your application. 

If you have any questions about this change, please contact the Guarantee team on 0800 269 119 or at

Kind regards,

Kirsty Forman

Product Manager