KOROK External Wall Systems: Integrated Facade Performance

As building performance requirements continue to evolve, designers and builders are looking for systems that deliver more than just a finished exterior. Fire safety, acoustic separation, weather protection, structural efficiency and construction speed are increasingly expected to work together within a single building envelope solution.

KOROK External Wall Systems have been developed to meet these demands, providing an integrated pre-cladding solution for commercial and industrial buildings. Combining fire resistance, acoustic performance and weather-tight protection in one lightweight assembly, the system helps create high-performance building enclosures that support New Zealand Building Code compliance while streamlining construction.

An integrated external wall solution

KOROK External Wall Systems are non-loadbearing, fire- and acoustically-rated external wall systems comprising a zinc-coated steel outer shell and a high-density 400kg/m³ aerated concrete core. The result is a durable and robust wall assembly that provides fire protection, sound control and external weather performance within a single system.

The panels are manufactured as 78mm-thick interlocking units with an effective cover width of 250mm. Installed vertically, they form a continuous barrier that maintains fire-resisting continuity while reducing opportunities for acoustic leakage through the wall assembly.

Unlike traditional wall build-ups that require multiple products to achieve compliance requirements, KOROK offers a consolidated approach that can reduce installation complexity and improve overall project efficiency.

Delivering performance before and after cladding

Pre-cladding systems play a critical role in protecting the building enclosure during construction and contributing to long-term building performance. KOROK External Wall Systems are engineered to provide durability and weather resistance from the outset while delivering ongoing operational benefits throughout the life of the building.

The zinc-coated steel outer shell provides a durable external barrier, while the aerated concrete core delivers inherent fire resistance and acoustic mass. Together, these components create a high-performing external wall solution suitable for demanding commercial and industrial environments.

Available in both single-skin and over-clad configurations, the systems can be selected to match project-specific design requirements while maintaining critical performance characteristics.

Fire and acoustic protection in one assembly

One of the key advantages of the KOROK External Wall System is its ability to combine high levels of fire and acoustic performance within a single wall assembly.

Depending on the selected configuration, systems can achieve two-way Fire Resistance Ratings (FRRs) ranging from –/120/120 minutes up to –/240/240 minutes, helping to limit the spread of fire between fire cells and adjacent areas.

Acoustic ratings range from STC 36 through to STC 76, making the systems well suited to applications where noise control is an important design consideration. The interlocking panel design enhances acoustic performance by reducing sound pathways while maintaining the fire integrity of the wall.

This combination makes KOROK particularly effective for warehouses, factories, cinemas, service areas, lift shafts and other commercial or industrial buildings where both fire separation and acoustic control are critical.

Supporting efficient building design

The lightweight nature of KOROK External Wall Systems can deliver significant project benefits. Compared with heavier wall construction methods, the system reduces demands on the primary structure, potentially lowering structural requirements and simplifying installation.

Because the wall assembly incorporates multiple performance functions within a single product, construction sequencing can be streamlined, helping contractors achieve faster enclosure of the building envelope.

The systems are designed and tested for New Zealand conditions and are engineered to perform under defined design wind pressures, providing confidence in long-term durability and serviceability.

Performance capabilities include:

Design wind pressures up to 1.76 kPa for EX1 and EX2 systems.
Design wind pressures up to 2.5 kPa for EX3, EX4 and EX5 systems.
Maximum unsupported vertical spans of 6.0 metres in fire-rated applications.
Compliance with structural design requirements for self-weight, wind, earthquake and impact loads in accordance with AS/NZS 1170.

A range of system options

KOROK External Wall Systems are available in five configurations to suit a variety of project requirements:

EX1 – 78mm COLORSTEEL panel single-skin system
EX2 – 78mm COLORSTEEL panel with internal fire-rated lining
EX3 – 78mm panel with engineered over-clad metal system
EX4 – Over-clad system with internal fire-rated lining
EX5 – Over-clad system with internal fire-rated lining

The over-clad systems incorporate drained and vented cavity cladding systems and can be engineered to meet project-specific performance requirements.

Designed for NZBC compliance

BRANZ-appraised and developed specifically for New Zealand conditions, KOROK External Wall Systems contribute to compliance across multiple New Zealand Building Code clauses, including:

B1 Structure
B2 Durability
C3 Fire Affecting Areas Beyond the Fire Source
C6 Structural Stability
E2 External Moisture
F2 Hazardous Building Materials

This broad compliance profile provides designers, specifiers and builders with a proven pathway to achieving robust building performance outcomes.

Building performance through system integration

As expectations for building performance continue to rise, integrated wall systems are becoming increasingly important. KOROK External Wall Systems demonstrate how a pre-cladding solution can contribute far beyond weather protection, delivering fire safety, acoustic separation, durability and construction efficiencies within a single assembly.

For commercial and industrial projects where performance, compliance and installation efficiency are key considerations, KOROK External Wall Systems provide a practical solution engineered for the realities of New Zealand construction.

KOROK® 78mm Colour Panel

KOROK® Fire and Acoustic Wall Systems

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High-performing and lightweight panels, 78mm KOROK® panels are engineered to provide exceptional performance in both fire and acoustic applications.

NZ Made

NZ-Owned Business

Post-Consumer Recyclable Content

Applications of 78mm KOROK® Colour Panels:

78mm KOROK® colour panels are versatile and suitable for various building applications, including:

KOROK® External Wall Systems: Ensuring robust protection with excellent thermal, acoustic, and fire-rated properties.
KOROK® Warehouse, Retail, and Factory Wall Systems: Providing high-performance solutions that meet the unique needs of commercial and industrial environments.

The NZBC sets out both the legal minimum sound transmission between tenancies (Clause G6) and minimum levels of fire resistance (Clauses C3 and C6). The KOROK® Intertenancy Systems Manual provides guidance on the specification and construction of systems that will both meet and exceed those minimum levels. However, designers must consider the comfort of occupants when selecting a system that will satisfy the occupants’ expectations when using the space rather than the minimum required by law.

Clause B1 – Structure: The KOROK® Systems meet the requirements for loads arising from self-weight, earthquake, wind, impact and creep and shrinkage.
NZBC Clause B2 – Durability: Under normal conditions of dry internal use, KOROK® Intertenancy Systems have a serviceable life in excess of 50 years and satisfy the requirements of NZBC Clause B2 - Durability.
NZBC Clause C3 — Fire affecting areas beyond the source: KOROK® Intertenancy Systems can be used to provide passive fire protection in accordance with the requirements of NZBC Clause 3 – Spread of fire
NZBC Clause C6 — Structural Stability: Compliance with (NZBC) Clause C6 ‘ Structural Stability’. In order to satisfy the requirements of the New Zealand Building Code (clause 6) relating to “structural stability” designers must ensure that KOROK® elements are supported by primary elements that have at least the same fire rating as the KOROK® system that is used. Where the primary elements supporting the KOROK® system are outside the fire cell, there is no requirement to apply the same FRR as the KOROK® system. Notwithstanding, post fire stability requirements of the NZBC must also be satisfied.
NZBC Clause G6 – Airborne and Impact Sound: KOROK® Intertenancy Systems, both meet and exceed the minimum requirements outlined in NZBC Clause G6. Consideration must be given to both the minimum requirements and the comfort of occupants.

BRANZ Appraised

Environmental Product Declaration (EPD)

KOROK® 78mm Galv Panel