Embodied carbon: meaning, measuring and mitigating
Article
Published on 05/08/2025
1. Introduction
Achieving net zero carbon is now a global imperative.
Understanding how to measure and mitigate embodied carbon in the built environment plays a pivotal role in reaching that goal. In this blog post, we’ll delve into what embodied carbon is, plus how to calculate and reduce it.
2. What is net zero carbon?
Net zero has been reached when the amount of carbon dioxide emitted into the atmosphere and the total removed from it are balanced. This ensures the overall impact on the environment is zero.
3. What is embodied carbon?
There are two types of carbon emissions associated with buildings and infrastructure.
One is operational carbon, which is linked to energy use in completed constructions, for purposes such as heating, cooling and lighting.
The other is embodied carbon, which is associated with materials – such as concrete, bricks, aluminium or steel – and construction processes. Embodied emissions occur throughout a building or infrastructure asset’s entire lifecycle, from materials’ extraction to their eventual disposal or recycling.
Those construction lifecycle stages are identified formally in European standard EN 15978. This provides a widely adopted methodology for assessing buildings’ environmental performance from cradle to grave. The phases the standard specifies are:
One is operational carbon, which is linked to energy use in completed constructions, for purposes such as heating, cooling and lighting.
The other is embodied carbon, which is associated with materials – such as concrete, bricks, aluminium or steel – and construction processes. Embodied emissions occur throughout a building or infrastructure asset’s entire lifecycle, from materials’ extraction to their eventual disposal or recycling.
Those construction lifecycle stages are identified formally in European standard EN 15978. This provides a widely adopted methodology for assessing buildings’ environmental performance from cradle to grave. The phases the standard specifies are:
| Stage | Description | Examples |
|---|---|---|
| A1–A3 | Product stage | Raw material extraction, processing, manufacture |
| A4–A5 | Construction stage | Transport to site, construction activities, such as installation |
| B1–B5 | Use stage | Maintenance, repair, replacement, refurbishment |
| C1–C4 | End-of-life | Demolition, transport, waste processing, disposal |
| D | Beyond building life | Reuse, recycling, energy recovery (optional credits) |
4. Why embodied carbon matters in UK construction
According to the World Green Building Council, embodied carbon can contribute up to 50 per cent of a construction’s total emissions over its lifetime. This is particularly likely where a building uses little energy or is already net zero. For infrastructure – such as bridges, tunnels and roads – embodied carbon often makes up 80 to 90 per cent of total emissions, due to its limited operational energy use.
This emphasis on operational carbon has been reflected in measures such as Part L (Building Regulations), which stress energy efficiency. It’s also evident in the national electricity grid decarbonising, through using power generated from renewable sources, which means operational emissions are falling. Embodied carbon, however, has remained largely unregulated.
Embodied carbon is locked in from day one. Unlike operational emissions, you can’t reduce it once a project is built. That’s why decisions at the design and procurement stage are so important.
Life cycle assessments (LCAs) evaluate the environmental impacts of materials or products at each stage of their existence. They’re being increasingly demanded by groups such as clients and regulators.
For example, the proposed Part Z (Building Regulations) would make LCAs mandatory, an intention supported by over 300 industry organisations.
In addition, the London Plan (policy SI 2) already requires professionals responsible for major developments to submit LCAs and embodied carbon benchmarking. These must be provided to the capital’s local council and its equivalents in areas such as Greater Manchester, Brighton and Cambridge, are following suit.
LCAs are also required for certification under:
For example, the proposed Part Z (Building Regulations) would make LCAs mandatory, an intention supported by over 300 industry organisations.
In addition, the London Plan (policy SI 2) already requires professionals responsible for major developments to submit LCAs and embodied carbon benchmarking. These must be provided to the capital’s local council and its equivalents in areas such as Greater Manchester, Brighton and Cambridge, are following suit.
LCAs are also required for certification under:
- The Leadership in Energy and Environmental Design scheme, a globally recognised system developed by the US Green Building Council.
- The Building Research Establishment Environmental Assessment Method, the world-renowned and widely adopted construction sustainability evaluation system.
We’ll say more about how to conduct LCAs in section 5.
Other relevant UK organisations driving towards reducing embodied emissions include:
Other relevant UK organisations driving towards reducing embodied emissions include:
- The Royal Institute of British Architects, whose 2030 Climate Challenge sets tight embodied carbon targets for members of that profession.
- The UK Green Building Council and Leti, member-led networks aiming to transform the built environment’s sustainability, which have issued benchmarks and frameworks.
- Authorities responsible for public procurement, who increasingly request low carbon materials and construction methods for buildings such as hospitals and schools.
5. Reducing embodied carbon
Here are some key strategies you can adopt to reduce embodied carbon in buildings and construction projects:
Selecting low carbon alternatives to traditional building materials can significantly lower embodied carbon. For example:
- Bamboo, timber and other bio-based materials
- Low carbon concrete alternatives, like the geopolymer and carbon capturing varieties. You can also look for Ground Granulated Blast Furnace Slag (GGBS) or fly ash content, as both are sustainable alternatives to traditional concrete ingredients.
The longer a building’s operational life, the more time it has to offset its embodied carbon emissions. Designing durable, adaptable and easily maintainable structures ensures the need for reconstruction or demolition is minimised, reducing embodied carbon over time.
Minimising waste, optimising material use and maximising efficiency can be achieved through:
- Designing for disassembly or deconstruction
- Efficient structural design, optimising spans, reducing over-specifications and avoiding superfluous finishes.
- Using advanced technologies, such as Modern Methods of Construction. These produce prefabricated or modular buildings, which are made in factories and merely assembled on-site.
Sourcing products locally can cut emissions associated with transportation. Materials produced near construction sites have much lower carbon footprints than those from further afield, due to their reduced shipping and logistics needs.
Repurposing existing buildings or materials is a highly effective way to reduce embodied carbon. Reuse eliminates the need to extract further raw materials, manufacture new products and transport them, all of which contribute to carbon emissions. It’s therefore advisable to pick materials that have been recycled, and which you are reusing or repurposing.
6. How to calculate and nullify embodied carbon
There are several steps involved in accurately calculating embodied carbon:
The first step is to compile a list of all the materials used in the building or infrastructure. This should include everything from concrete, steel, glass and insulation to finishes like flooring, paint and fixtures.
The next stage is performing an LCA, which we defined in section 3.
An LCA is typically conducted using specific software tools, such as our own NZC Hub, One Click LCA or Athena. These provide data on materials’ carbon intensity and compare the amount emitted per unit of different products.
An LCA is typically conducted using specific software tools, such as our own NZC Hub, One Click LCA or Athena. These provide data on materials’ carbon intensity and compare the amount emitted per unit of different products.
The carbon intensity of materials is expressed in carbon factors. A carbon factor is a coefficient that quantifies the amount of the gas a product releases into the atmosphere.
Factors are measured in kilograms of carbon dioxide equivalent (kgCO2e) per unit of material. They’re derived from industry standards and published environmental product declarations (EPDs), which provide verified data on the carbon footprints of construction materials. European Standard EN 15804 provides a framework for
creating construction product EPDs.
The carbon factor of concrete is typically higher than that of wood, for example, due to the energy-intensive process of manufacturing cement, which typically constitutes 10 to 15 per cent of its content.
Factors are measured in kilograms of carbon dioxide equivalent (kgCO2e) per unit of material. They’re derived from industry standards and published environmental product declarations (EPDs), which provide verified data on the carbon footprints of construction materials. European Standard EN 15804 provides a framework for
creating construction product EPDs.
The carbon factor of concrete is typically higher than that of wood, for example, due to the energy-intensive process of manufacturing cement, which typically constitutes 10 to 15 per cent of its content.
Using its carbon factor and quantity, you can then calculate the total embodied carbon for each material in a project.
For example, if a building uses 100 cubic metres of concrete and the carbon factor for concrete is 200 kgCO2e per cubic metre, the embodied carbon for the concrete used would be:
100 m³ x 200 kgCO2e/m³ = 20,000 kgCO2e
You can repeat this for every material used in a project to get a total embodied carbon value for the building or infrastructure.
For example, if a building uses 100 cubic metres of concrete and the carbon factor for concrete is 200 kgCO2e per cubic metre, the embodied carbon for the concrete used would be:
100 m³ x 200 kgCO2e/m³ = 20,000 kgCO2e
You can repeat this for every material used in a project to get a total embodied carbon value for the building or infrastructure.
Once you’ve calculated the embodied carbon of all materials, you can compare the total with emissions from a building’s operational phase, due to energy use. To achieve net zero carbon, the total emissions from of both types must be nullified.
This can be achieved through adopting mitigation strategies, like implementing carbon offsets and using renewable energy, or deploying carbon removal technologies.
The most common form of offsetting is buying carbon credits. These involve emitters effectively donating to certain projects that help sustain the planet, such as schemes involving tree planting or harnessing solar power. The idea is that each credit you purchase authorises you to emit a tonne of carbon.
Removal technologies use elements such as tiny organisms, that can only be seen via microscopes, to retrieve, capture and store carbon that would otherwise be emitted into the atmosphere.
This can be achieved through adopting mitigation strategies, like implementing carbon offsets and using renewable energy, or deploying carbon removal technologies.
The most common form of offsetting is buying carbon credits. These involve emitters effectively donating to certain projects that help sustain the planet, such as schemes involving tree planting or harnessing solar power. The idea is that each credit you purchase authorises you to emit a tonne of carbon.
Removal technologies use elements such as tiny organisms, that can only be seen via microscopes, to retrieve, capture and store carbon that would otherwise be emitted into the atmosphere.
7. Checklists
| Material | Approximate CO₂e/tonne | Key notes |
|---|---|---|
| Cement (CEM I or Portland cement, the most widely used type) | 850–950 kg | One of the biggest carbon sources. |
| Ready-mix concrete | 100–300 kg | Depends on the mix and the GGBS content. |
| Reinforcing steel (UK) | 1,200–1,800 kg | Lower with recycled content and using the Electric Arc Furnace method of manufacture. |
| Aluminium | 6,000–12,000 kg | Extremely high unless recycled. |
| Bricks | 250–450 kg | Varies by process and location. |
| Glass (float) | 1,000–2,000 kg | Often overlooked in façades |
| Timber | Negative or low | This is classed as biogenic, as it’s derived from living organisms, and can store carbon. |
Here’s a bullet-point guide to how you can help minimise embodied emissions if you’re a:
- Contractor
- Influence material use, waste and site emissions.
- Reduce carbon through construction logistics, sequencing and prefabrication.
- Track emissions from fuel, equipment and subcontractors.
- Developer
- Define the carbon brief early in the design process. This should be a comprehensive report outlining a project’s intended environmental impact, including both its embodied and operational emissions.
- Set embodied carbon budgets or targets, early in the design process.
- Work with suppliers offering verified low carbon products.
- Choose teams with experience in low-carbon design.
- Product Manufacturer or supplier
- Provide verified EPDsfor your output.
- Shift towards cleaner production, by using electric arc furnaces to make steel, for example.
- Offer take-back schemes, modular systems or low-carbon alternatives to traditional products.
- Tools and databases:
- NZC Pro. This is an intuitive lifecycle carbon assessment calculator and reporting tool for UK projects. It enables you to calculate your development’s emissions through the tender, construction and as-built stages.
- NZC Hub. This enables you tocalculate your building’s whole lifecycle embodied carbon emissions. Backed by a bespoke UK third-party verified specific database, it covers the design, technical, construction and post completion stages.
- Tally. This lifecycle assessment tool is effectively part of the Autodesk Revit building information modelling software application, widely used by groups such as architects and contractors.
- Inventory of Carbon and Energy Database. This is a regularly updated UK-based facility containing data on embodied emissions for over 200 common building products, divided into 30 categories.
- EPDs
8. Conclusion: embodied carbon and the path to net zero
The construction industry accounts for about 40 per cent of all global carbon emissions. The world’s net zero targets therefore cannot be met unless the sector tackles embodied carbon.
That’s why the industry is increasingly being held accountable by groups such as clients, local authorities and investors.
Responsibility therefore lies with professionals like architects, engineers and builders to adopt strategies and tools that reduce embodied carbon footprints.
If they act now, adverse outcomes close to home likestranded assets, costly retrofits or being locked out of procurement frameworks can be avoided.
But, more importantly, the sector can be a part of the global solution to climate change. It can achieve this by advocating low-carbon construction practices, supporting sustainable building standards and prioritising the use of materials with low embodied carbon. Every step towards minimised embodied carbon brings the world closer to a sustainable and climate-resilient future.
That’s why the industry is increasingly being held accountable by groups such as clients, local authorities and investors.
Responsibility therefore lies with professionals like architects, engineers and builders to adopt strategies and tools that reduce embodied carbon footprints.
If they act now, adverse outcomes close to home likestranded assets, costly retrofits or being locked out of procurement frameworks can be avoided.
But, more importantly, the sector can be a part of the global solution to climate change. It can achieve this by advocating low-carbon construction practices, supporting sustainable building standards and prioritising the use of materials with low embodied carbon. Every step towards minimised embodied carbon brings the world closer to a sustainable and climate-resilient future.
See how our tools such as the carbon calculator software for construction and carbon reporting software for construction can help your business today.
