Arahia is a five-townhouse development on a compact urban site, requiring precise coordination between architectural intent, spatial efficiency, and regulatory performance. The design comprises two-level white bagged brick volumes stepping up the site, with interstitial garages providing clear articulation between units while supporting privacy and rhythm along the façade. Dense landscaping reinforces separation between dwellings and circulation zones. Central to the project was the performance of the intertenancy walls, which needed to meet fire, acoustic, and spatial requirements without adding construction complexity or compromising internal floor area.

The Challenge: Intertenancy Performance Without Compromise

As with many terraced housing developments, intertenancy walls at Arahia needed to achieve more than structural separation. The walls were required to:

• Meet stringent fire resistance requirements for attached dwellings
• Deliver strong acoustic performance to support quiet, comfortable living
• Be space-efficient, preserving valuable internal floor area
• Integrate seamlessly with a modern construction programme

Meeting all of these criteria within a compact building envelope demanded a system that was robust, compliant, and efficient to install.

KOROK® Intertenancy Solution

KOROK supplied 290m² of KOROK® 51mm Galv Panels, installed as part of the KOROK® Intertenancy Terraced Housing System.

The system delivers a -/60/60 Fire Resistance Rating, suitable for intertenancy walls in terraced housing and fully compliant with the New Zealand Building Code (NZBC). Unlike conventional framed and lined systems, the KOROK® panel itself forms the primary fire barrier, providing inherent durability and long-term resilience.

Panels are positioned between double wall frames and connected via aluminium brackets engineered to respond predictably in fire conditions—allowing the fire-exposed side to detach while maintaining the integrity of the barrier on the protected side.

KOROK® for Modern Terraced Housing

The Arahia project demonstrates how KOROK® Intertenancy Systems are well suited to contemporary townhouse developments—where protection, performance, and efficiency must coexist. By combining engineered fire resistance, acoustic control, and slimline design, KOROK continues to support safer, smarter, and more liveable medium-density housing across New Zealand.

Related Projects

The Ravenscroft Fire and Smoke Damper has been carefully engineered to seamlessly integrate with high performance KOROK wall systems. Preventing the spread of both fire and smoke between building compartments, preserving the barriers integrity for up-to two hours.

The Ravenscroft Fire Damper for KOROK is a combined balancing and fire damper. The damper can easily be tested and preset with the indicator handle from outside the duct. Duct access panels are not required. The Ravenscroft Smoke/Fire Damper for KOROK is a combined fire and smoke damper. The damper can easily be tested by pressing the centre of the thermo-electric tripping device. Flexible ductwork connectors must be used to separate rigid ducting from the damper. These prevent excess force being transferred to the wall mounting in the advent of ductwork deformation or collapse during a fire or earthquake.

Available sizes

125 | 150 | 175 | 200 | 250 | 300 | 400mm (125 and 175 available by request)

Recent Articles

When discussing construction techniques, one important aspect to consider is panel handling, which ensures safety and efficiency on site.

Panel Handling

KOROK manufactures lightweight wall panels consisting of galvanised or colour steel shells filled with aerated concrete.

Generally, KOROK products are delivered to your building or other site on long trailers and articulated trucks.

Our products are packed with reasonable protection against damage during delivery, however care must be exercised during unloading.

Forklift, Hiab or crane unload is required.

GUIDELINES

Ensure packs are lifted slowly, avoiding jerking where possible.

Forklift unloading – 150mm between pack and mast.

Ensure soft slings are neatly running on the inside of the two most inner timber collars of the pack.

Ensure soft slings are running continuously from the hooks to underneath the pack and back up to the hook.

Do not loop the sling around itself with only one end connected to the hook. This may damage the panels when lifted.

Ensure you lift only one or two packs at a time.

PACK SIZES

The panels are packed in timber pallets, measuring 1200mm wide by 300mm high.

There will be 2, 4 or 6 timber pallets for each pack (depending on length), nominally spaced 1200mm apart, middled from pack centre.

Packs can be stacked up to 6 packs high and must be placed side by side or end on end, on the truck / trailer tray.

When stacking back-to-back, timber collars must butt up against each other.

The length of the pack will vary according to the length of the panel required by the customer, commonly between 2.0 and 7.0 metres in length (can be up to 9.0m).

COMMON PACK WEIGHTS

Standard 3 metre pack = 390 – 470kg (nominal); Standard 6 metre pack = 780 – 936kg (nominal).

STRAPPING DOWN PACKS

Loads must be strapped down and secured by appropriate means. Load strops are most highly recommended, allowing 12 to 16 strops for a full semi load, more for B-Train transport.

Packs are to always be strapped over timber collars. No belly straps done with plastic angles at any time.

When stacking higher than 4 packs, a second set of straps must be placed after the third pack over timber collars only, before adding further packs.

ACCESSORIES

At times, a bundle of steel C-track or Angle strips may be placed on top of the load. These may measure up to 6.0 metres in length and weigh from 10kg to 500kg depending on the quantity.

IN TRANSIT

Where possible, avoid sudden braking and jolts during transit to reduce impacts on the product.

Re-tension strops every two hours at a minimum.

UNLOADING

Forklift, Hiab or crane unload is required.

Use soft slings or forks only, no chains to be used on product.

All lifting to only be done under middle crate, closest to the bearers to take the weight.

Forklift unloading – 150mm between pack and mast.

Care must be taken on unload and storage of product, avoiding bumps and scratching.

Guidelines must be carefully followed (turn over page).

Tested, Trusted, and Designed for Demanding Environments

KOROK® manufactures high‑performance fire‑ and acoustic‑rated wall panels engineered for New Zealand construction. Our panels are precision‑formed, lightweight, and designed to deliver reliable compliance and long‑term durability across a wide range of building applications. Explore our product range, available in both 78 mm and 51 mm panel options.

CASE STUDY

Boathouse Bay: A Showcase of Sustainable Community Living

Located at Snells Beach, just north of Auckland, Boathouse Bay by Crosson Architects has set a new standard in environmentally-conscious design, winning the prestigious title of Home of the Year 2024. This award-winning project offers a perfect blend of architecture and nature, creating a community-focused environment that celebrates New Zealand’s coastal lifestyle.

Innovative Design with a Coastal Influence

Inspired by the traditional Kiwi bach, Boathouse Bay reflects simplicity and connection to nature. The development embraces natural materials, muted tones, and open communal spaces, fostering a sense of unity among its residents. The layout encourages interaction, with thoughtfully designed pathways connecting homes to shared outdoor areas, reinforcing the idea of community living.

KOROK’s Role in Enhancing Safety and Sustainability

Central to Boathouse Bay’s design is the use of 51mm KOROK Intertenancy Terraced Housing Systems, which offer superior fire protection without compromising the project’s environmental goals. Our fire-rated systems ensure that the development remains safe, durable, and sustainable. The aluminum brackets included in the KOROK system safeguard the structure in the event of a fire, reinforcing both safety and structural integrity for terraced housing.

Setting a Benchmark for Future Living

Boathouse Bay is more than just a residential development—it’s an example of how modern, community-focused living spaces can integrate sustainability, safety, and social interaction. As the Home of the Year 2024, it stands as an inspiration for future projects that aspire to merge contemporary design with environmental stewardship.

Related Projects

[ymc_filter id=”3454″]

High Performing and Lightweight

51mm KOROK® panels are rollformed from zinc coated steel strips. The steel from which the shells are manufactured conforms to AS/NZS1397:2001. Steel shells have a base metal thickness of 0.4mm B.M.T. with a Z275 zinc coating. These panels have an aerated concrete core and weigh nominally 10.2kg per lineal metre.

KOROK® produces 51mm panel. KOROK® 51mm panel provides a -/60/60 FRR and is perfectly suited for terraced house intertenancy walls and apartment intertenancy walls.  The narrower gauge allows you to keep more floor space as it isn’t taken up by walls.

Performance and Features

• Fire Rating: KOROK® 51mm panels provide a fire resistance rating of -/60/60 FRR, meeting stringent safety requirements for intertenancy walls in terraced houses and apartments.
• Acoustic Efficiency: Designed to reduce sound transmission, these panels ensure quieter living environments, making them an excellent choice for densely populated or high-traffic areas.
• Space-Saving Design: The 51mm thickness allows for slimmer walls, helping to maximize valuable floor space without compromising structural integrity or performance.

KOROK® 51mm Galv panels are used for:

• KOROK® Intertenancy Terraced Housing Wall Systems
• KOROK® Intertenancy Apartment Wall Systems

Applications and Systems

• Vertical Orientation: Panels are installed vertically and secured to timber or steel framing with aluminum brackets.
• Versatility: Compatible with wall framing, insulation, and linings specified within the system appraisal, ensuring seamless integration into your building project.
• Scope of Use: Appraised for all buildings of all importance levels as defined by AS/NZS 1170.