Building Materials
Embodied Carbon in Building Materials: Why It Matters Early in Design
Building materials can shape a project’s embodied carbon long before construction begins. Structure, façade systems, material quantities and reuse decisions are often set early, which makes early carbon review especially valuable.
When project teams think about building performance, they often begin with operational energy. This includes heating, cooling, lighting, hot water and the energy a building uses once it is occupied.
But a building also carries carbon impacts before anyone moves in. These impacts are connected to the materials used to create the building, including extraction, manufacture, transport, construction and sometimes replacement or end of life treatment.
This material related impact is known as embodied carbon. It can be influenced by structure, façade design, material quantities, product choices, construction methods, reuse opportunities and the way a building is designed to last over time.
In Brief
Why building materials matter for embodied carbon
Material choice
Concrete, steel, timber, aluminium, glass, insulation and finishes can all influence embodied carbon outcomes.
Material quantity
A material used across a large part of the building can drive the result even when its carbon intensity is moderate.
Design timing
The most useful carbon decisions are often made before structure, spans, façade systems and major specifications are locked in.
What Is Embodied Carbon in Building Materials?
Embodied carbon refers to the greenhouse gas emissions associated with building materials and construction processes. Depending on the assessment scope, this may include emissions from raw material extraction, manufacturing, transport, installation, replacement and end of life treatment.
In simple terms, embodied carbon is the carbon impact connected to creating the building, rather than only operating it. For materials, this can include emissions linked to cement production, steel manufacturing, aluminium smelting, glass production, timber processing, insulation manufacturing and many other supply chain activities.
For a broader introduction to the concept, read What Is Embodied Carbon in Buildings?
Design Insight
Embodied Carbon Is Often Locked In Early
Many embodied carbon outcomes are shaped in early design. Once the structural system, façade approach, grid, spans, material palette and demolition strategy are set, a project may have fewer opportunities to reduce material related emissions without affecting cost, programme or design intent.
This is why embodied carbon is not only a reporting issue. It is also a design issue. A report prepared late in the process can document carbon impact, but an assessment considered earlier can help the project team compare options while decisions are still flexible.
Early review can help identify whether the largest impacts are likely to come from concrete, steel, aluminium, glazing, façade systems, finishes or other major building elements.
Why Materials Matter in Embodied Carbon Reporting
Building materials do not all affect embodied carbon in the same way. Some materials have a high carbon intensity because of the energy and processes involved in producing them. Others may have a lower carbon intensity but still matter because they are used across large parts of the building.
Concrete can be significant because it is often used in large quantities. Aluminium can be important because it can carry a high carbon intensity. Steel can become a major factor where it forms a large part of the structure. Façade systems can matter because they combine glass, aluminium, framing, fixings, coatings and replacement cycles.
For a more focused material hotspot guide, read Which Construction Materials Have the Highest Embodied Carbon?
Material System
Structure
Structural systems are often central to embodied carbon because they can involve large quantities of concrete, steel, timber, masonry or composite systems. Structural decisions can affect material volumes, spans, load paths, durability and future adaptability.
For this reason, embodied carbon reporting is often most useful when architects, engineers and sustainability consultants can review structure early, before the main system is fixed.
Material System
Façades and Glazing
Façade systems can influence both operational and embodied carbon. Glazing, frames, cladding, shading, insulation, coatings and fixings all carry material impacts, while the façade also affects heating, cooling, daylight and comfort.
This makes façade design an important part of carbon aware architecture. For more detail, read Façade Systems and Embodied Carbon
Material System
Finishes, Insulation and Building Products
Finishes, insulation and building products may not always dominate the result in the same way as structure, but they can still be relevant. Their impact depends on quantities, product type, replacement cycles, durability and available product specific data.
In some projects, repeated replacement over time can make certain products more important than they first appear. This is why assessment boundaries and life cycle stages matter.
How Material Choices Can Reduce Embodied Carbon
Reducing embodied carbon does not usually come from one single material substitution. It is more often the result of coordinated decisions across design, engineering, specification and procurement.
For a broader guide to material strategies, read Low Embodied Carbon Building Materials
Reuse Before Replacement
The Role of Adaptive Reuse
One of the most powerful material related carbon decisions can be whether to retain existing building fabric. Reusing structure, façade elements or major building components can reduce the need for new materials and avoid some emissions associated with demolition and replacement.
Adaptive reuse is not always possible or simple. Existing buildings may need upgrades for safety, access, energy performance, services, durability and compliance. However, where reuse is viable, it can become a meaningful embodied carbon strategy.
For more detail, read Adaptive Reuse and Embodied Carbon
How an Embodied Carbon Report Helps with Material Decisions
An embodied carbon report helps project teams move from general assumptions to project specific information. Instead of assuming which materials matter most, the assessment can identify where the largest carbon impacts are likely to occur in the actual design.
This can help architects, engineers, developers and builders compare options, review material quantities, understand façade and structural impacts and document the assumptions behind the assessment.
For more on report scope, read What Is Included in an Embodied Carbon Report?
FAQ
Common Questions About Embodied Carbon in Building Materials
Which building materials usually affect embodied carbon the most?
Concrete, steel, aluminium, glass and some façade systems can be significant, but the result depends on the design. A material with moderate carbon intensity may still be important if it is used in large quantities.
Can embodied carbon be reduced after materials are selected?
Sometimes, but the options are usually more limited. Earlier review gives project teams more flexibility to compare structural systems, reduce material quantities, consider lower carbon products and review reuse opportunities.
Is timber always lower carbon than concrete or steel?
Not automatically. Timber can support lower carbon outcomes in some projects, but the assessment still depends on quantity, source, product data, durability, treatment, transport, replacement assumptions and the overall structural design.
Why does façade design matter for embodied carbon?
Façades can include glass, aluminium, cladding, insulation, fixings, coatings and shading systems. They can also influence operational energy, daylight and comfort, which makes façade decisions important in both carbon and performance reviews.
Related Guidance
Continue Reading About Embodied Carbon
What Is Embodied Carbon?
A broader introduction to embodied carbon in buildings.
Highest Embodied Carbon Materials
A focused guide to material hotspots in construction.
Low Embodied Carbon Materials
Practical ways to think about lower carbon material choices.
Concrete, Steel and Timber
A deeper comparison of common structural materials.
Project Review
Need to understand the material related carbon impact of your 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.
Visit the Embodied Carbon Report Knowledge Hub
