Embodied Carbon Materials
Which Building Materials Usually Drive Embodied Carbon?
Some materials carry more embodied carbon weight than others. But in a real building project, the answer is rarely as simple as naming one material as good or bad.
Embodied carbon is shaped by material intensity, quantity, structure, façade design, supply chains, construction methods and the life of the building itself. A material used sparingly may have less overall impact than a lower-intensity material used across the whole building.
This is why embodied carbon reporting is useful. It helps project teams move beyond assumptions and see where the largest material-related emissions are likely to sit within a specific design.
High Volume
Materials such as concrete can matter because they are used in large quantities.
High Intensity
Materials such as aluminium can matter because their carbon intensity can be high.
Major Systems
Structure, façades and glazing often deserve close attention in embodied carbon reporting.
Understanding Material Hotspots in Embodied Carbon
In many building projects, embodied carbon is concentrated in a small number of major systems. These often include the structure, concrete, steel, aluminium, glazing, façade systems and other high-volume or high-intensity materials.
These materials are not automatically wrong choices. They often play essential roles in safety, durability, performance, buildability and architectural quality. The important question is how they are used, how much is needed and whether the same design outcome can be achieved with a lower-carbon approach.
An embodied carbon assessment gives the project team a clearer way to understand those decisions. Rather than treating materials in isolation, it looks at the building as a whole. For a broader introduction, read What Is Embodied Carbon in Buildings?.
Material Hotspot
Concrete: High Impact Because of Scale
Concrete is often one of the most important materials in an embodied carbon assessment because it is used in large quantities. Slabs, footings, columns, walls, cores and other structural elements can all make concrete a major contributor to a building’s total embodied carbon.
The carbon impact of concrete is strongly influenced by cement content. Cement production is energy-intensive and releases carbon dioxide during manufacturing. Because concrete is used at such scale, even modest changes in mix design, structural efficiency or material quantities can influence the overall result.
Lower-carbon concrete strategies may include optimised structural design, reduced cement content, supplementary cementitious materials, efficient slab and footing design, reuse of existing structure or project-specific concrete mixes where suitable. These decisions need to be coordinated with the structural engineer and project team.
Material Hotspot
Steel: Essential, Strong and Carbon-Intensive
Steel can also be a significant embodied carbon contributor, especially in structural frames, reinforcement, long-span systems, façade supports, roofing, bridges and infrastructure projects.
The carbon profile of steel depends on the production method, recycled content, energy source, specification and quantity used. Different steel products can have different embodied carbon impacts, especially where product-specific data is available.
Reducing steel-related embodied carbon can involve using steel more efficiently, reducing unnecessary over-specification, coordinating structural spans, considering reuse where practical and selecting recycled-content options where they meet the project requirements.
Material Hotspot
Aluminium: Smaller Quantities, Higher Intensity
Aluminium is often used in smaller quantities than concrete or steel, but it can carry a high embodied carbon intensity because of the energy required for primary aluminium production.
In buildings, aluminium commonly appears in window frames, curtain wall systems, façade components, shading devices, balustrades and architectural elements. On façade-heavy buildings, this can become a meaningful part of the embodied carbon profile.
Recycled aluminium can reduce impact, depending on the product, supply chain and available data. However, the result still depends on quantity, durability, replacement cycles and how the façade system performs as a whole.
Glass, Glazing and Façade Systems
Façade systems are often important because they sit at the intersection of embodied carbon, operational energy, comfort, daylight, glare, durability and architectural expression.
Glazing can influence heating and cooling demand while also carrying embodied carbon through glass, framing, coatings, seals, fixings and supporting systems. A highly glazed or complex façade may have a different carbon profile from a simpler, more efficient envelope.
For embodied carbon reporting, the façade is often more useful to review as a system than as a list of separate products. For more detail, read Façade Systems and Embodied Carbon.
Timber and Lower-Carbon Material Choices
Timber is often discussed as a lower-carbon material option, particularly where it can reduce reliance on more carbon-intensive structural or finishing materials. In some projects, timber can support a lower embodied carbon strategy.
However, timber still needs to be assessed carefully. Its carbon profile depends on responsible sourcing, forestry practices, processing, transport, treatment, durability, end-of-life assumptions and how biogenic carbon is treated in the assessment method.
For a focused comparison of major structural materials, read Concrete, Steel and Timber Embodied Carbon.
Why Quantity Matters as Much as Carbon Intensity
One of the most common misunderstandings in embodied carbon is focusing only on the carbon intensity of a material.
Carbon intensity matters, but so does quantity. A high-intensity material used sparingly may contribute less to the whole building result than a moderate-intensity material used throughout the structure.
This is why concrete can be a major embodied carbon driver because of volume, while aluminium can become important because of intensity. The result depends on the building type, design, specification and quantities involved.
Common Strategies for Reducing Material-Related Embodied Carbon
Reducing embodied carbon usually requires a combination of design, engineering, specification and procurement decisions. There is rarely one simple substitution that solves the whole problem.
The right strategy depends on the project. A commercial tower, apartment development, school, warehouse, infrastructure project or residential dwelling may each have different embodied carbon drivers. For related guidance, read Low Embodied Carbon Building Materials.
How an Embodied Carbon Report Helps
An embodied carbon report helps project teams identify where the largest material-related emissions are likely to occur. This makes the discussion more specific and more useful than general assumptions about which materials are high or low carbon.
The report can help compare design options, review material choices, understand structural and façade impacts and document the assumptions behind the calculation.
For more on reporting scope, read What Is Included in an Embodied Carbon Report?.
The Bottom Line
Embodied carbon depends on material choice, quantity and design context.
Concrete, steel, aluminium, glazing and façade systems often deserve close attention, but the answer always depends on the project.
Certified Energy can review your project documentation and advise whether an embodied carbon report, Life Cycle Assessment, NABERS Embodied Carbon pathway or another reporting approach may be relevant.
