Evaluation of the Environmental Sustainability of Hemp as a Building Material, through Life Cycle Assessment

Environmental issues, especially those related to the over-exploitation of natural resources, are leading towards considering alternative solutions and new approaches, such as the circular economy. Currently, some key elements of the circular economy approach are sustainable procurement of raw materials, improvement of production processes and ecological design, adoption of more sustainable distribution and consumption models, development of secondary raw material markets. This work aims to analyse the use of hemp as a building material, replacing traditional construction materials, but respecting at the same time the thermal, insulating and acoustic characteristics required in the construction of a building. The methodology used was Life Cycle Assessment (LCA), which considered the hemp cultivation phase and the production phase of hemp-lime (“hempcrete”) walls. The hempcrete product was compared with two different solutions: a hemp and lime block, and a traditional perforated brick block with external insulation in polystyrene. In particular, the differences among the products in terms of embodied energy and net CO₂ emissions were analysed. Results showed that the hempcrete wall had better environmental performances than the other two solutions.