Natural builders often try to minimise the use of concrete and cement, but completely avoiding them isn’t always practical.

Concrete still has a place in natural construction. It is commonly used for foundations, slabs, retaining walls, piers, and situations where durability, structural capacity, or resistance to moisture are critical. In many regions, particularly rural Australia, locally sourced stone suitable for traditional foundation work can be difficult or expensive to obtain. In those cases, a carefully designed concrete foundation may be the most practical solution.

Concrete can also help solve some building science challenges. It provides thermal mass, helping moderate indoor temperatures when used appropriately within the building envelope. It can also be useful in reducing thermal bridging when combined with insulation strategies, and in some assemblies it can assist with moisture management by providing a durable and stable base beneath vapour-permeable wall systems.

The challenge is that cement—the binding ingredient in conventional concrete—comes with a significant environmental cost. Cement production is responsible for roughly 7–8 per cent of global carbon dioxide emissions, making it one of the largest industrial sources of greenhouse gases worldwide. While concrete itself is durable and long-lasting, its embodied carbon footprint sits uneasily alongside the goals of natural and regenerative building.

So what do we do when concrete appears necessary, but conventional cement doesn’t align with our environmental values?

A recent article from The Fifth Estate highlights an interesting paradox. Despite decades of Australian research and tens of millions of dollars invested in low-carbon alternatives, greener forms of concrete remain a niche product. The problem is not that the technology doesn’t work. According to the article, geopolymer concrete has demonstrated technical advantages over conventional Portland cement concrete, including improved durability, fire resistance and resistance to chemical attack. It can also reduce embodied carbon by up to 80 per cent. Yet uptake remains slow.

The article focuses on the experience of Earth Friendly Concrete, developed by Wagners, and the broader work of SmartCrete CRC. Their frustration is revealing: the barriers are no longer primarily technical or economic. Instead, they are institutional. Engineers, clients, contractors and government agencies remain cautious about specifying unfamiliar materials, even when those materials have strong performance records and competitive pricing.

One of the most striking observations is that sustainability itself is often not enough to drive adoption. The company now markets its geopolymer concrete primarily on performance benefits rather than environmental credentials because clients respond more readily to durability and reduced maintenance than to carbon savings.

For natural builders, this raises an important question. If concrete cannot always be eliminated, should our focus shift towards dramatically reducing its carbon footprint instead?

Perhaps the path forward is not a choice between “concrete” and “no concrete”, but rather using the minimum amount required, designing for longevity, and supporting lower-carbon alternatives where they are available.

The original article is well worth reading:

Green concrete clients, we have a problem, and it’s not the superior tech nor the price – The Fifth Estate.

Photo credit – Low Embodied Carbon Guide

Further Reading :

• SmartCrete CRC — Australian research cooperative focused on decarbonising concrete and cement.
• Think Brick Australia – Thermal Mass Guide — Useful information on thermal mass and building performance.
• Australian Hemp Masonry Company — Information on hemp-lime construction as a lower-carbon wall system.
• YourHome Australia — Government-backed guidance on thermal mass, insulation, condensation, and moisture management.
• Australian Passivhaus Association — Resources on thermal bridging, airtightness, and vapour management.
• Earth Friendly Concrete (Wagners) — Australian geopolymer concrete technology.
• ASBP – Embodied Carbon Primer — Australian Sustainable Built Environment resources on embodied carbon.