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A Comprehensive Guide to Carbon Emissions of Building Materials

Discover how the choice of building materials impacts carbon emissions—and the climate—throughout the construction lifecycle.

By Medha deb

Created on Sep 27, 2025

Discover how the choice of building materials impacts carbon emissions—and the climate—throughout the construction lifecycle.

Understanding Carbon Emissions in Building Materials

Buildings are responsible for a vast share of global carbon emissions. A significant portion of these emissions comes not from heating or powering occupied structures, but from the materials used in construction—throughout their manufacturing, transportation, use, and afterlife. This guide breaks down exactly how building materials contribute to carbon emissions, the factors that influence these impacts, and what designers, builders, and consumers can do to reduce their environmental footprint.

The Two Big Components: Operational vs. Embodied Carbon

Carbon emissions in buildings are typically divided into two main categories:

Operational Carbon: Emissions from the energy used to heat, cool, light, and power a building over its lifetime.
Embodied Carbon: Emissions from manufacturing, transporting, constructing, maintaining, and disposing of the building’s materials—regardless of how “efficient” the building is to operate.

As buildings become more energy efficient, operational carbon is falling, but embodied carbon is becoming increasingly significant—a trend that spotlights the importance of materials selection from the very beginning of a project.

Embodied Carbon: What It Encompasses

The embodied carbon of a material refers to the total greenhouse gas emissions generated throughout its life cycle. This includes:

Extraction: Mining or harvesting raw materials.
Processing: Manufacturing and refining materials (e.g., making cement, smelting steel).
Transport: Moving materials to factories, then to construction sites.
Construction: Assembly and finishing on site.
Maintenance: Ongoing repairs, replacements, or upgrades during the building’s life.
Disposal: What happens at end-of-life—landfilling, recycling, or reuse.

This life-cycle approach, known as cradle-to-grave analysis, is key to understanding and mitigating a building’s full impact.

How Building Materials Compare: Carbon Footprints by Type

Not all materials are created equal. Some, like concrete and steel, are notorious for high emissions, while others like sustainably harvested wood can be far lower-impact.

Material	Typical Embodied Carbon	Key Impact Factors
Concrete	Very High	Cement production is responsible for ~8% of global CO2 emissions. Cement and kiln fuels are main drivers.
Steel	High	Production is energy-intensive and fossil fuel reliant, though recycling mitigates some impacts.
Brick/Masonry	Moderate to High	Firing bricks consumes significant energy.
Wood (Lumber, Mass Timber, CLT)	Low to Negative*	Acts as a carbon sink during growth; emissions hinge on sustainable practices and longevity of use.
Gypsum Board (Drywall)	Moderate	Energy required for calcining and refining gypsum.
Aluminum	Very High	Electrolytic reduction process is extremely energy-intensive, but recycling reduces impact.
Reclaimed Materials	Very Low	Reuse minimizes need for new production and landfill.

*”Negative” refers to carbon sequestration through use of wood, provided the forest is managed sustainably and the wood is stored in use for long periods.

Digging Deeper: Carbon Emissions by Material

Concrete

Concrete is the world’s most used construction material and among the top sources of manmade carbon emissions. The main culprit is cement, an essential binder that requires extremely high-temperature kilns and releases CO2 in the chemical reaction involved in its manufacture. Together, the cement industry accounts for roughly 8% of the world’s annual CO2 emissions.

Efforts to reduce concrete’s footprint include replacing part of the cement binder with fly ash or slag, and developing alternative binders.
Recycling concrete or using precast products may help lower overall emissions.

Steel

Steel is prized for its strength, but its carbon footprint is high due to the fossil fuels used in its production, especially during the transformation of iron ore in blast furnaces.

Electric arc furnaces, which use recycled steel, can significantly cut emissions compared to making steel from raw ore.
Designing structures for adaptability and recycling keeps steel in productive use and out of landfills.

Wood & Mass Timber

Wood is often viewed as a carbon-friendly choice, not only because trees absorb CO2 while growing, but because harvested wood retains that carbon. If forests are replanted and managed well, and wood is kept in long-term use (such as mass timber construction), the sequestration effect is maximized.

Wood products often have 60% lower emissions than comparable concrete or steel assemblies, according to numerous building life-cycle analyses.
If sourced unsustainably, or if wood decomposes or burns at the end of its life, some or all of the stored carbon may be released back into the atmosphere.
Preserved wood use and wood recycling amplify climate benefits.

Reclaimed and Recycled Materials

Reclaimed and recycled building materials (like salvaged wood, reused brick, or recycled metal) usually have vastly lower embodied carbon. By averting demand for new resource extraction, manufacturing, and transport, reclaimed materials reduce not only carbon emissions but also landfill waste.

Opting for reclaimed lumber provides the environmental benefit of carbon storage without necessitating further harvesting of forests or the emissions tied to processing new wood.
Challenges include supply constraints, quality assessments, and removal of old hazardous treatments.

How Builders and Designers Can Cut Embodied Carbon

Building professionals and consumers have a growing toolkit to lower embodied carbon:

Material Substitution: Replace carbon-heavy materials (e.g., concrete or steel) with lower-impact alternatives where possible, like wood, bamboo, or compressed earth.
Use of Supplementary Materials: Incorporate materials like fly ash or slag into concrete mixes to reduce the need for new cement.
Maximize Recycling and Reuse: Source reclaimed or recycled materials when available, and design new buildings for future adaptability and deconstruction.
Life Cycle Analysis (LCA): Evaluate the full impacts using LCA tools to compare materials and design options before building begins.
Sourcing Locally: Reduce transportation emissions by choosing materials that are produced nearby.
Sustainable Certification: Specify certified sustainable forestry or low-carbon manufacturing processes.

Innovation in Green Building: Novel Materials and Methods

The construction industry is innovating at speed. Some of the most promising strategies and materials for reducing emissions include:

Mass Timber and Cross-Laminated Timber (CLT): Large wood structural panels and “mass timber” systems now allow wood to replace concrete and steel even in mid- and high-rise construction, with substantial carbon savings.
Green Concrete: Next-gen concrete mixes reduce cement or use alternative binders, cutting process emissions and sometimes even absorbing CO2 during curing.
Phase Change Materials (PCMs): These smart materials integrated into buildings can actively reduce the need for heating and cooling, indirectly saving operational energy and associated emissions.
Bio-based Materials: Natural fibers (hemp, straw), cork, mycelium (fungi), and more are entering mainstream construction, offering rapid renewability and sometimes carbon-negative footprints.

Frequently Asked Questions (FAQ)

Q: What is the single biggest driver of high embodied carbon in buildings?

A: The production and use of cement (especially Portland cement) in concrete is the top contributor, responsible for around 8% of global carbon emissions.

Q: How does using wood instead of steel or concrete lower emissions?

A: Wood stores carbon absorbed during the tree’s growth, and its processing generally requires less energy than steel or concrete, resulting in up to 60% lower emissions in studies comparing equivalent building systems.

Q: Are reclaimed and recycled materials always better for the climate?

A: Usually yes, since they bypass new production, extraction, and disposal. That said, some reclaimed materials require additional processing, potentially offsetting some benefits, and prior chemical treatments must be carefully checked.

Q: What are some emerging options for reducing embodied carbon?

A: Innovations such as mass timber, low-carbon concrete (with alternative binders or CO2 curing), and advanced insulation made from plant fibers or recyclable content are on the rise, helping to push embodied carbon even lower.

Q: Where can I find data comparing the carbon impacts of different materials?

A: Publicly available databases like the Inventory of Carbon and Energy (ICE) and resources from organizations like Circular Ecology and regional green building councils are useful starting points.

Quick Reference: Tips for Builders and Homeowners

Select materials with sustainability certifications (e.g., FSC for wood, third-party eco-labels for others).
Favor reclaimed, recycled, or local materials whenever possible.
Request Environmental Product Declarations (EPDs) from suppliers for transparent emissions data.
Design buildings for disassembly—making it easy to reuse materials in the future.
Consider the building’s full lifecycle, not just construction costs and aesthetics.

Conclusion

Tackling the carbon emissions of buildings means looking beyond energy efficient appliances or insulation. The very materials we choose are just as critical—from cradle to grave. By prioritizing low-carbon, responsibly sourced materials, leveraging innovations in green building, and committing to a full life-cycle perspective, designers and builders can be key contributors to a more sustainable climate future.

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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