Potential of clay-based plaster for improving thermal inertia in lightweight constructions: Analytical and experimental investigations

Abstract

Lightweight, bio-based walls often suffer from low thermal inertia, leading to sensitivity to external temperature fluctuations. This study explores how clay-based plaster can enhance this behaviour through analytical and experimental investigations. The analytical approach highlights the role of internal areal heat capacity and show that increasing the effusivity and thickness of the inner plaster layer improves the wall’s dynamic thermal response. Experimental results demonstrate that applying the studied clay plaster increases the internal surface heat capacity of wood walls from 16.8 kJ·m⁻²·K⁻¹ to 60.8 kJ·m⁻²·K⁻¹, which represents about 90% of the value observed in heavier structures. These findings provide practical insights into the use of earthen coatings to enhance thermal inertia and energy performance in lightweight construction systems.