Sustainable slab Insulation - Cupolex

Insulating your home is an essential step of the building process to ensure you live in a warm, dry house that meets the New Zealand building standards. The first step of home insulation starts with the concrete slab. Polystyrene blocks are often the first go-to product to meet these needs, but little thought is put into the environmental impacts that they have. These blocks use a considerable amount of waste in both the manufacturing and building processes. And in addition to waste, they are also a hazard to the environment. When not disposed of correctly, the offcuts are slow to degrade, they can leach into the ground and get into our waterways, harming wildlife and causing many years of damage.

For these reasons, Rangitahi has recently banned the use of polystyrene blocks in foundations. We encourage the use of sustainable and eco-friendly materials whenever possible. Another alternative to polystyrene blocks is Cupolex. Cupolex is a recycled insulation system made in New Zealand that exceeds the NZ building standards and is a zero-waste product. We caught up with Malcolm Cottle, the national accounts & operations manager of Cupolex to tell us more about this great product.

Can you give us a quick overview of Cupolex, what is it used for, and the benefits?

Cupolex is essentially a sacrificial permanent formwork that is used for residential and commercial foundations. Invented in 1995 in Italy, Cupolex utilises the strength created from the arch combined with the concrete and reinforcing to create a honeycomb effect for your foundation. The advantage of this approach is not only the strength but also because the foundation is all connected, it makes for a naturally warmer floor. Globally they have been building structures like bridges and cathedrals using this technology for thousands of years and still to this day, many of them remain. It also means that there is no cutting of product to suit the foundation layout. Which makes it extremely efficient to construct with zero-waste eliminating the need for a skip bin at the very beginning of your new build.


Rangitahi backs this product as an alternative for polystyrene bocks. Can you tell us why Cupolex is a better alternative?

Cupolex is manufactured using 100% recycled plastic created from waste in NZ. This means that not only are we able to reduce landfill, but also create a product that can be recycled at the end of the building's life. Cupolex as previously mentioned, requires no cutting of its components, as opposed to polystyrene, where you need to cut it to fit. This creates a very problematic situation as the small beads then become airborne or blow along the ground and settle into nearby environments like waterways, farmland and reserves. The animals, fish and birds that live in these environments then mistakenly see the beads as food and ingest it, which is not good news for them!Cupolex is compactly packed onto pallets (52m2 per pallet) this not only reduces transport costs but also minimises site traffic for existing residents in the community and cuts down on the carbon footprint from delivery vehicles.

Rangitahi focuses on sustainability and creating energy-efficient housing. How does Cupolex help with these initiatives?

To create insulation you need to trap air in an enclosed space. Because of the "void" that is formed from the Cupolex, which traps air beneath the concrete slab and the DPM (damp proof membrane), the foundation maintains a consistent mass within the remaining envelope of the building to heat or cool. As manufacturers continue to use plastics for packaging, electronics, toys and fixings and fittings, to name just a few, there will always be a waste product. We take this manufacturer's and consumer's waste and create the Cupolex product that can also be recycled at the end of life.

The Cupolex concept

New building codes are coming in from October. Does Cupolex meet the new government's requirements for insulation?

Yes we do. Cupolex has had independent testing carried out in New Zealand to determine that we meet the new H1 regulations for the NZ Building code, and we exceed them. How long has Cupolex been around for in NZ, and is it widely used? Cupolex has been available in NZ since 1995. However, the full product range that is now available in NZ only started being manufactured here in 2017 by the current owner. Cupolex is widely used throughout NZ, with projects ranging from Schools, gyms, chicken farming sheds, early child care centres, lifestyle villages, as well as the work that we do with both individual and group home builders.

How would someone find out more about Cupolex and consider it for their build?

We can be contacted via:
Phone: 0800 CUPOLEX 2876539

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