Recent research highlights the potential of hemp-based materials in reducing the carbon footprint of the construction industry. A study conducted by Jay Arehart, a professor at the University of Colorado-Boulder, has provided valuable insights into how hempcrete, an insulation material made from hemp and lime, can effectively store carbon in buildings. This innovative approach offers builders and designers a new metric for evaluating materials based on their environmental impact.
Dynamic life cycle assessment (LCA) is a critical tool in this evaluation process. It tracks building materials from production to disposal, measuring both carbon storage and emissions. The BEAM Estimator, developed by Chris Magwood of Builders for Climate Action, enables builders to select materials based on their carbon storage capabilities versus their lifecycle emissions. This tool is instrumental in promoting sustainable building practices by facilitating informed decision-making.
In his 2020 paper published in the Journal of Cleaner Production, Arehart explored the carbon sequestration potential of hempcrete. His research revealed that buildings could potentially store more carbon than they emit, challenging conventional views on building emissions. Arehart’s inquiry into carbon storage led him to focus on biomaterials like hemp, which have a rapid growth cycle and significant carbon absorption capabilities.
Hempcrete stands out as a compelling alternative to traditional building materials due to its unique properties. When combined with lime binders, which also sequester carbon, hempcrete becomes an attractive option for builders aiming to minimize their environmental impact. Arehart’s team analyzed various hempcrete mix designs to assess their carbon storage capabilities, concluding that hempcrete can store approximately -16 kg (-7.3 lbs) of carbon per square meter (10.76 square feet) of wall assembly after accounting for production emissions.
The implications of this research are significant. Magwood emphasizes the importance of recognizing the positive impact of carbon removal from the atmosphere in LCA methodologies. Traditional assessments often overlook this aspect, but Arehart’s work contributes to a more comprehensive understanding of hempcrete’s environmental benefits.
Arehart’s analysis includes detailed calculations of emissions throughout the production process, encompassing everything from growing the hemp and producing lime to transportation and mixing. He notes that cementitious materials like lime can sequester CO2 even while emitting it during production, further enhancing the appeal of hempcrete as a sustainable building material.
The versatility of hemp as an insulation material is noteworthy. Arehart points out that comparing materials requires considering their functional properties in addition to their carbon footprints. For instance, while concrete and steel serve different structural purposes, evaluating them on a full life cycle basis, including durability and strength, provides a clearer picture of their environmental impact.
Hempcrete’s ability to enable builders to create carbon-zero structures is gaining traction within the industry. Magwood reports successful projects where net-zero carbon residences have been achieved using hempcrete. He asserts that it is feasible to construct buildings that sequester more CO2 than they emit by strategically selecting materials with high storage capacity.
The BEAM calculator serves as a practical resource for architects and builders, listing the carbon footprints of various materials and allowing for informed comparisons based on project specifications. Jacob Waddell from the U.S. Hemp Building Foundation highlights that as carbon capture becomes increasingly vital in material selection, Arehart’s foundational work positions hemp as a competitive option in sustainable construction.
Hemp-based materials like hempcrete offer a promising solution for reducing the construction industry’s carbon footprint. As awareness grows regarding the environmental impacts of traditional materials, innovative alternatives such as hemp are poised to play a pivotal role in shaping sustainable building practices for the future. By prioritizing materials that minimize emissions and actively capture and store carbon, builders can contribute to a more sustainable built environment while addressing climate change challenges head-on.
