Understanding Embodied Carbon
When we think about the environmental impact of buildings, we tend to focus on operational energy, the electricity and fuel consumed to heat, cool, and light the building over its lifetime. But a significant and often overlooked portion of a building's total carbon footprint comes from the materials themselves. Embodied carbon refers to the greenhouse gas emissions associated with extracting, manufacturing, transporting, and installing building materials. As operational energy efficiency improves through better insulation and renewable power, embodied carbon represents an increasingly large share of a building's total lifecycle emissions.
Comparing the embodied carbon of different building materials reveals dramatic differences in environmental impact. These differences matter enormously for anyone making material choices on construction projects, from individual homeowners to large-scale developers. At Lumber New Orleans, we believe that informed material selection is one of the most powerful tools available for reducing the construction industry's contribution to climate change.
Concrete and Steel: The Carbon Heavyweights
Concrete is the most widely used building material in the world, and it is also one of the most carbon-intensive. The production of Portland cement, the key ingredient in concrete, involves heating limestone to over 2,600 degrees Fahrenheit in massive kilns. This process releases carbon dioxide both from the fuel burned to generate the heat and from the chemical decomposition of limestone itself. Cement production alone accounts for roughly eight percent of global carbon dioxide emissions, making it one of the single largest industrial sources of greenhouse gases.
Steel production is similarly carbon-intensive. Manufacturing virgin steel from iron ore in blast furnaces requires enormous amounts of coal and produces roughly 1.8 tons of carbon dioxide per ton of steel. While recycled steel has a significantly lower carbon footprint, the steel industry as a whole remains a major contributor to global emissions. Structural steel framing, while strong and versatile, carries a heavy embodied carbon burden that is difficult to offset through other means.
New Lumber: Better, But Not Perfect
New wood products have a much lower embodied carbon footprint than concrete or steel. Trees absorb carbon dioxide as they grow, and that carbon remains stored in the wood after harvesting and throughout the product's service life. This carbon sequestration partially offsets the emissions generated during harvesting, milling, kiln drying, and transportation. On a per-unit basis, new dimensional lumber and engineered wood products like cross-laminated timber have embodied carbon levels that are a fraction of those for steel or concrete performing the same structural function.
However, new lumber is not carbon-neutral. Logging operations consume fuel. Sawmills use significant energy for processing and kiln drying. Transportation from forest to mill to distributor to job site adds further emissions. And perhaps most importantly, the harvesting of forests can reduce the carbon sink capacity of the landscape, an indirect emission that is difficult to quantify but ecologically significant. The environmental performance of new lumber also depends heavily on the sustainability of forestry practices, with certified sustainable forests performing much better than operations that deplete forest resources faster than they regenerate.
Reclaimed Lumber: The Lowest Carbon Option
Reclaimed lumber has the lowest embodied carbon footprint of any structural building material. Because the wood has already been harvested, milled, and put into service, the original emissions from those processes are attributed to the first-use building, not the reclaimed product. The only new emissions associated with reclaimed lumber are those from salvage, processing, and transportation, which are typically a small fraction of the emissions generated by producing new lumber or any other structural material.
Furthermore, using reclaimed lumber keeps carbon stored in the wood rather than allowing it to be released through decomposition in a landfill or combustion in a waste-to-energy facility. When a building is demolished and its wood is sent to a landfill, the decomposition process releases methane, a greenhouse gas roughly 28 times more potent than carbon dioxide over a 100-year period. By intercepting this material and putting it back into service, reclaimed lumber dealers like Lumber New Orleans are actively preventing greenhouse gas emissions while providing a high-quality building product.
Quantifying the Difference
Research has consistently shown the carbon advantages of reclaimed wood. Studies comparing the lifecycle emissions of equivalent structural systems find that reclaimed timber framing produces 50 to 75 percent fewer greenhouse gas emissions than new timber framing, and 90 percent or more fewer emissions than equivalent steel or concrete systems. For a typical residential project using reclaimed lumber, the carbon savings can amount to several tons of avoided carbon dioxide emissions, a meaningful reduction at the individual project level that becomes transformative when scaled across the industry.
These numbers are increasingly relevant for projects pursuing green building certifications, carbon neutrality commitments, or compliance with emerging embodied carbon regulations. Several jurisdictions are now implementing policies that require or incentivize reductions in embodied carbon for new construction. Reclaimed materials are among the most effective strategies available for meeting these requirements, and reclaimed lumber in particular offers a proven, available, and high-performing option.
Making Lower-Carbon Choices
Every building project involves hundreds of material decisions, and each one is an opportunity to reduce carbon impact. Choosing reclaimed lumber where possible, selecting sustainably sourced new wood where reclaimed is not available, and minimizing the use of carbon-intensive materials like concrete and steel are all strategies that contribute to a lower-carbon built environment. At Lumber New Orleans, we are committed to making reclaimed lumber accessible and practical for projects of all types and scales, because we believe that the material choices we make today will shape the climate our children inherit tomorrow.