Influence of Insulation Placement on the Hygrothermal Performance of Hemp Concrete Walls

This study develops a coupled heat air moisture (HAM) model to assess the hygrothermal response of bio-based porous materials used in building envelopes. The numerical framework was first verified against HAMSTAD benchmark cases that explicitly account for the influence of air transport on moisture migration. The predicted fields show good agreement with the reference solutions, supporting the accuracy of the proposed implementation. The validated model was subsequently applied to a multilayer wall assembly integrating hemp concrete as a bio-based insulating layer. Temperature and relative humidity distributions were evaluated as a function of time and position across the wall under representative summer boundary conditions for Agadir, Morocco, characterized by a hot and dry climate. The simulations indicate that hemp concrete attenuates temperature fluctuations and moderates moisture variations within the envelope, which can contribute to improved indoor comfort and reduced moisture-related risks. Overall, the findings underline the suitability of hemp concrete as an energy efficient and durable insulation material for warm climates and highlight the added value of locally available bio-based resources for enhancing building environmental performance.