Hygrothermal assessment of a traditional earthen wall in a dry Mediterranean climate

In this paper, we define the hygrothermal properties of a rammed earth wall through experimental analysis, relating thermal parameters to moisture content. These tests were conducted in Campo de Criptana (Ciudad Real, Spain), and the wall examined in this study is a 70-cm-thick north-facing rammed earth wall that is part of an occupied traditional dwelling Ambient and surface temperature and humidity values were monitored, along with the temperature and humidity at several points inside the wall and the heat flux on both sides of the wall. We recorded the wall’s behaviour regarding ambient comfort conditions for one year and obtained transmittance and conductivity values. Results show that it is quite difficult to analyse the hygrothermal behaviour of a rammed earth wall throughout the year, since the properties of the wall vary enormously. We found that, to evaluate the thermal behaviour of the wall, it was not appropriate to consider the same conductivity value for whole sections of the wall, as this value varies according to moisture content (generally between 0.39 and 0.55 Wm⁻¹ K⁻¹): we propose seasonal values for conductivity. Finally, the hygrothermal stability that these structures provide to the spaces they enclose has been shown, especially during hot and dry periods.