Compressed-straw SIPs Panel

Structural Compliance in Portable Homes

NCC 2022 Volume 2

Area of NCC Requirements:

• H1P1 – Structural Reliability & Termite Management
• H4P1 – Wet Area Waterproofing
• H4P7 / H4P8 – Condensation & Water Vapour Management

The Challenge

As the industry moves toward low-carbon and high-performance housing, alternative wall systems such as compressed-straw Structural Insulated Panels (SIPs) are gaining traction. These systems offer exceptional thermal performance, reduced embodied energy, and rapid construction, but they also sit outside the NCC’s Deemed-to-Satisfy (DTS) pathways.

For this residential project in NSW, the straw-based SIP system served as both the structural wall frame and the primary thermal envelope. Because the NCC does not include DTS provisions for this type of natural-fibre panel, a performance solution was required to demonstrate compliance across three critical areas:

• Termite risk management
• Wet area protection
• Condensation and moisture control

Without a clearly defined compliance pathway, regulatory acceptance cannot occur — regardless of how promising the technology may be.

What This Really Means

When a building system is not covered by the NCC’s prescriptive rules, it must still demonstrate that it performs at least as well as a conventional, DTS-compliant wall. For straw-based SIPS, this means proving that the structure remains protected from moisture, termites, and long-term deterioration, and that the walls behave safely under normal household conditions.

The Solution

A performance solution was developed to confirm that the straw-panel wall system achieved the NCC’s intent across structural durability, termite resistance, wet-area moisture protection, and condensation management.

The assessment considered:

• How the proposed system maintains structural integrity over time
• Whether termite-management measures would be durable, continuous, and inspectable
• How wet areas can be detailed to avoid moisture migration into the panel core
• Whether the building envelope prevents condensation accumulation in a cool-temperate climate
• How ventilation, moisture buffering, and vapour-control strategies support long-term occupant health
• How the system’s performance compares with that of a conventional timber-framed assembly

By reviewing manufacturer documentation, building-physics modelling, and relevant Australian Standards, the solution demonstrated that the system delivers performance outcomes equivalent to — and in some respects better than — common DTS wall constructions.

Why This Matters

The final report confirmed that the straw-based SIP system satisfied the relevant performance requirements for structural reliability, termite management, wet-area protection, and condensation control.

This project showcases how emerging construction technologies can be successfully integrated into Australian housing when supported by a robust performance-based assessment. It also reinforces an important industry lesson: innovation doesn’t need to conflict with compliance — it simply needs a clear and defensible pathway.

Is the NCC preventing new technology usage on your project? 

Reach out to our team for the solution.