CodeMark-certified, Masons’ Enviro AAC Intertenancy Wall System gives builders a faster, lighter way to meet New Zealand’s strict requirements for fire and acoustic performance.
A simpler, safer intertenancy wall: Masons’ Enviro AAC system
Case Study
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June 9th, 2026
For developers of townhouses and terraced housing, getting the intertenancy wall design right is one of the more consequential decisions on site. The ease of installation and guaranteed compliance made Enviro AAC panels an unqualified success, according to CETA Homes Project Manager David Hall, who trialled the system in a 13-unit townhouse development in Pukekohe, Auckland.
‘This was a simple two-storey box form, and the Masons panel gave us all the fire rating we needed. We added mineral wool in the roof and cladding cavity, and that was it. There was no need to line for noise either, because the acoustic rating was taken care of too.’
Dense yet lightweight for rapid installation
The heart of the system is Masons’ 50-mm autoclaved aerated concrete panel (AAC), which is lightweight, dense and non-combustible, providing a complete fire and acoustic solution for intertenancy walls.
‘The panels are about a quarter of the weight of traditional concrete,’ says Arthur Whitfield, Masons technical manager, ‘and the system can be installed continuously up to three storeys, making it practical for multi-residential builds.’
‘What stood out was how straightforward it was to install,’ says Hall. ‘With a simple bracket-and-channel set-up, it was easy to get a clean, straight line from the start. It helped keep things moving on site and gave the team confidence in the outcome.’
Engineered for fire and acoustic compliance
Exceeding NZBC requirements for both soundproofing and fire resistance, the Enviro system gives builders and developers peace of mind that their intertenancy walls will be compliant when installed correctly.
‘For fire resistance, the Building Code requires only 30 minutes in most situations, but our AAC panel system offers a Fire Resistance Rating of 120 minutes,’ notes Whitfield. ‘We have put this system through rigorous tests at accredited New Zealand laboratories, successfully demonstrating resistance to extreme heat, upwards of 800 to 1000 degrees Celsius.’
For acoustic performance, the finished wall assembly achieves an STC rating of 64 – well above the minimum requirement of 55 for intertenancy walls, making homes built with the Enviro system more desirable to prospective buyers and tenants.
A proven solution for multi-dwelling construction
With its ease of installation and CodeMark certification, architects and specifiers can have confidence in Masons’ Enviro AAC Intertenancy Wall System. Designed to solve the challenges of intertenancy walls in multi-unit dwellings, the system goes up quickly and easily. Though lightweight, the non-combustible panels offer good noise reduction and, once combined with an air gap and the density of traditional plasterboard, help to create quieter, safer, more liveable homes.
Talk to our specification team
For more information on the Enviro AAC Intertenancy Wall System, including installation and compliance documents, visit mpb.co.nz or call 0800 522 533 to speak with one of our team.