Low-Carbon Material
Building products that carry fewer embodied emissions than their conventional equivalents.
Quick Answer
A low-carbon material is a building product whose embodied emissions, measured as global warming potential over its production stages, are lower than a conventional product serving the same function. Examples include concrete with supplementary cementitious materials, steel made from recycled scrap, and wood products. The claim should be verified with an EPD, not assumed.
The Full Picture
The term matters because a handful of materials, chiefly cement-based products and steel, produce a large share of a building's embodied emissions. Reducing carbon at the material level is often more practical than redesigning the whole building, since many substitutions keep the same performance and form.
Common approaches include cutting clinker content in concrete by replacing part of the cement with supplementary cementitious materials such as fly ash, slag, or calcined clay; using steel produced in electric arc furnaces with high recycled content; choosing timber and other bio-based materials where structurally appropriate; and reusing materials. Each approach has tradeoffs in strength gain, availability, or cost that need to be checked with the design team.
Low-carbon is relative, so it has to be defined against a baseline. An EPD with verified GWP for the specific product is the reliable way to show a reduction, and it should be compared to a like-for-like conventional product or an industry average. Terms like green or sustainable on a data sheet do not substitute for numbers.
In preconstruction, material choice is where carbon targets become procurement. The team asks suppliers for EPDs, checks the supply chain and lead time for lower-carbon options, adjusts means and methods such as curing time for concrete mixes with high replacement levels, and weighs any cost premium. Early supplier engagement avoids last-minute surprises.
Real Examples
Common Misconceptions
People assume: Natural or bio-based materials are automatically low carbon.
Actually: Impacts depend on sourcing, processing, and how biogenic carbon is counted. Verified data is needed rather than assuming a material class is low carbon.
People assume: Low-carbon materials always cost more.
Actually: Premiums vary widely. Some options, such as mixes with higher supplementary cementitious content, can be price-neutral in some markets, while others cost more or have limited supply.
People assume: A single manufacturer's claim is enough proof.
Actually: Without third-party verified EPD data and a clear baseline, a low-carbon claim cannot be checked or compared.
Frequently Asked Questions
What counts as a low-carbon material?
A product whose verified global warming potential is lower than a comparable conventional product. Typical examples are concrete with reduced clinker, recycled-content steel from electric arc furnaces, and certain wood products. The comparison should be made with EPDs.
How do I verify a low-carbon claim?
Request a third-party verified EPD, check that its declared unit and system boundary match your use, and compare its GWP with a baseline for the same product type.
Which materials matter most for embodied carbon?
Concrete and steel typically account for most upfront carbon in commercial buildings, so substitutions in those categories usually produce the largest reductions.
Are low-carbon materials harder to procure?
Availability varies by region and product. Early engagement with suppliers and attention to lead times and performance requirements reduces the risk.
How do low-carbon materials affect the schedule?
Some, such as high-replacement concrete mixes, can gain strength more slowly, so confirm stripping and loading timelines with the engineer and adjust sequencing if needed.