What was the challenge?

One New Zealand stadium demanded a single roof build‑up that could deliver significant rain‑noise attenuation and achieve high STC performance. Moreover, it had to control internal acoustics by containing crowd noise within the stadium environment without losing the atmosphere and energy created when the crowd comes alive.

Acoustically, the roof system had to double as a sound absorber. With a perforated liner tray exposing the underside of the insulation to view, the visible face needed a deep, uniform black aesthetic without compromising acoustic transparency. In other words, sound entering through the perforations had to be absorbed effectively to reduce reverberation in the seating bowl and concourses, while the underside still looked refined from below.

On the thermal side, the brief called for performance levels that typically push blanket insulation into high density, high thickness territory. In conventional practice, that often forces multiple layers and added complexity to maintain continuity over large spans. To maximise material handling and performance complexity, the solution consolidated the thermal acoustic build‑up into a single, high‑density layer, reducing the installation time.

All of this had to be delivered as a coordinated system balancing weight, durability, and installation efficiency.

At the same time, it still needed to meet the non-combustibility, health and sustainability objectives expected of a modern stadium, including occupant comfort, indoor air quality, responsible material choices and lower operational energy.

What was the solution?

Knauf Insulation delivered a combined thermal and acoustic roof assembly that met the stadium’s demanding performance brief while streamlining installation. Using TwinTech manufacturing technology, a high‑density (35 kg/m³), high‑thickness (75mm) bespoke Roof blanket was able to be produced. This approach preserved continuity across large spans, reduced interfaces, and helped the team achieve the required thermal performance with predictable sequencing and less on‑site complexity — ideal for high‑performance roofing systems.

The insulation was installed as a bottom layer behind a perforated liner tray, making the underside visible from below.

The product was designed with a black facing for a uniform, refined appearance through the perforations. For acoustics, a black glass veil facing was selected so that it would not undermine the insulation’s ability to absorb sound, enabling the system to reduce reverberation in the bowl and concourses while still contributing to the roof’s thermal targets.

Beyond performance, the solution also supported key health, safety and sustainability objectives. Fewer layers meant less handling at height and reduced site waste, while improved thermal efficiency helps lower operational energy over the building’s life. Knauf Insulation Roof blanket also brought the reassurance of non-combustible performance, an important consideration for stadium safety, alongside market-leading EPDs and Certified Red List Free status to support responsible material selection. Together, these qualities helped deliver occupant comfort, strong indoor environmental quality and a durable, consistent finish designed to perform over the long term.

“Te Kaha Stadium was a standout project for RoofLogic and one we are incredibly proud to have delivered," says Alisha Gutsell, South Island Architectural Consultant, RoofLogic. "The system needed to do far more than provide a roof and façade — it had to meet demanding structural, seismic and acoustic requirements while working with a highly complex design. By developing a bespoke envelope solution, we were able to achieve the performance the project called for, from long‑span capability and weather‑tightness through to exceptional acoustic control. The end result is a system that not only meets the specification, but helps create the atmosphere and energy that will make the stadium such a special venue.”