NZ Concrete Group
Modern ThermaCast insulated concrete home

ThermaCast™ by NZ Concrete Group

Concrete Homes NZ

ThermaCast is our insulated in-situ concrete wall system, purpose-built for New Zealand conditions. It combines the structural strength of reinforced concrete with integrated insulation to deliver homes that are warmer, stronger, quieter, and built to last generations.

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What Is ThermaCast?

The name ThermaCast derives from the Greek thermos— meaning warm or heat — combined with ‘cast’, reflecting the in-situ concrete pour at the heart of the system. Warmth built in from the ground up.

The ThermaCast wall is a composite system: polystyrene insulation is sandwiched between two reinforced concrete panels — an outer skin and an inner skin — poured in a single in-situ operation. Both faces are concrete. The inner face acts as thermal mass, absorbing heat during the day and radiating it back at night. The outer face forms the structural and weather envelope. No separate insulation trade. No timber framing. One pour, one wall.

The result is a home that exceeds Building Code H1 requirements, resists seismic and wind loads, and requires virtually no structural maintenance over its lifetime. Developed over three decades by NZ's most reputable high-end residential concrete home builders, ThermaCast is engineered for our climate, our seismic conditions, and our way of life.

For Architects

Design freedom. Both faces concrete.

ThermaCast™ gives architects something timber frame never can: two concrete surfaces to design with. The outer face can carry any architectural finish — off-form, exposed aggregate, board-formed, or polished. The inner face is raw concrete, acting as thermal mass and interior feature in one.

Complex geometry is achievable. Curved walls, cantilevered forms, double-height spaces, and non-rectangular floor plans are all within scope — the in-situ pour adapts to the formwork, not the other way around.

We work directly with architects and their engineering teams from concept through to specification. Early engagement is encouraged — we help optimise wall build-ups, connection details, and forming sequences before documentation is finalised.

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NZ Concrete Group crew erecting ThermaCast walls on a residential build
Worker assembling ThermaCast formwork panels on site
ThermaCast insulated concrete wall system under construction

Why Build with ThermaCast

Every ThermaCast home is designed to outperform conventional construction across the metrics that matter most.

Thermal Performance

Integrated insulation within the concrete wall assembly delivers continuous thermal performance, dramatically reducing heating costs and exceeding NZ Building Code requirements.

Seismic Resilience

Reinforced concrete is inherently stronger than timber framing. ThermaCast homes are engineered to exceed NZS 3101 standards, providing exceptional performance in earthquake-prone regions.

Durability

Concrete does not rot, warp, or attract borer. A ThermaCast home requires minimal structural maintenance and is built to perform for 100 years and beyond.

Sound Insulation

The mass of concrete provides outstanding acoustic separation. ThermaCast walls significantly reduce external noise transmission compared to standard timber-framed construction.

Fire Resistance

Concrete is non-combustible and maintains structural integrity under extreme heat. ThermaCast homes offer superior fire protection compared to timber construction.

Design Flexibility

Because ThermaCast is poured in-situ, it accommodates complex curves, cantilevered elements, and architectural features that are difficult or impossible with prefabricated systems.

Explore ThermaCast

Dive deeper into the system, the performance data, and what it costs to build a concrete home in New Zealand.

How It Works

How It Works

The ThermaCast build process explained step by step.

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Energy Performance

Energy Performance

Thermal and energy data for ThermaCast homes.

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Cost Guide

Cost Guide

What a concrete home costs in NZ in 2026.

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Designs

Designs

Browse our concrete house design range.

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Concrete vs Timber Frame

Concrete vs Timber Frame

An honest comparison of the two build methods.

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Project Gallery

Project Gallery

See completed ThermaCast homes across NZ.

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Recent Work

A selection of recent residential concrete projects across New Zealand.

Completed townhouse development
ThermaCast wall construction in progress
Modern residential units
Luxury concrete home with pool
Multi-unit townhouse development
Modern two-storey concrete build
ThermaCast construction on site
ThermaCast residential build in progress
Curved concrete staircase being formed with rebar — architectural complexity
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Build a concrete home in your region

NZ Concrete Group builds ICF insulated concrete homes across all major New Zealand regions.

Concrete Homes Auckland →Concrete Homes Hamilton →Concrete Homes Wellington →Concrete Homes Christchurch →Concrete Homes Tauranga →Concrete Homes Rotorua →Concrete Homes Queenstown →

Ready to Build a Concrete Home?

Talk to our team about your build, your site, and how ThermaCast can deliver the home you have been planning.

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FAQ

Frequently Asked Questions

What is ThermaCast™ and how does it differ from standard concrete construction?
ThermaCast™ is NZ Concrete Group's insulated in-situ concrete wall system. Polystyrene insulation is sandwiched between two reinforced concrete skins — an outer structural and weather skin, and an inner thermal mass skin — all poured in a single on-site operation. Unlike standard concrete walls, the insulation is permanently integrated, eliminating the need for a separate insulation trade.
How does a ThermaCast home compare to timber frame in terms of cost?
The concrete shell of a ThermaCast home typically costs more upfront than a timber frame structure. However, when whole-of-life costs are considered — lower energy bills, no structural maintenance, no re-cladding, no rot or pest treatment — the economics often favour concrete. Our cost guide provides current per-square-metre ranges for standard, premium, and architectural builds.
Is ThermaCast suitable for New Zealand's seismic conditions?
Yes. ThermaCast walls are reinforced concrete engineered to NZS 3101 and designed for New Zealand's seismic zones. Solid concrete walls provide inherent mass and ductility that timber framing cannot match. Every ThermaCast home is engineered by a structural engineer specific to the site and seismic zone.
How long does it take to build a ThermaCast concrete home?
A standard ThermaCast home typically takes 12–18 months from consent to completion, similar to a well-run timber frame project. The concrete shell phase is fast — walls are formed and poured in a matter of weeks. The programme is then driven by fit-out trades, the same as any other build.
Can I use my own architect with the ThermaCast system?
Yes. We work with client-appointed architects and designers. We encourage early engagement — involving us at concept stage ensures the design takes full advantage of what in-situ concrete can do, and avoids detailing that is difficult or costly to form. We provide technical support and specification assistance throughout the design process.
What energy performance can I expect from a ThermaCast home?
ThermaCast walls exceed NZ Building Code H1 thermal requirements. The integrated insulation eliminates thermal bridging through framing members, and the inner concrete face provides passive thermal mass — absorbing heat during the day and releasing it at night to stabilise indoor temperatures. Most ThermaCast homeowners report significantly lower heating and cooling costs compared to their previous timber frame homes.
Does ThermaCast work on sloping or difficult sites?
Yes. The in-situ concrete method is well suited to sloping sites, split levels, and challenging ground conditions. Retaining walls and foundations can be integrated into the same concrete structure, simplifying the build and reducing the number of contractors required on site.

The ThermaCast™ wall construction method is the intellectual property of NZ Concrete Group Ltd. © 2026 NZ Concrete Group Ltd. All rights reserved.