9. Investigating the Thermal Properties of Earth-Based Materials: The Case of Adobes

Earth-based materials have been receiving a growing interest in recent years due to their “rediscovery” as eco-friendly building materials with great potential to increase energy efficiency. Despite this interest, however, there is a lack of reliable scientific research data regarding the thermal properties of earth-based materials, which would allow a deeper understanding of their environmental performance. This work reviews current approaches on the thermal properties of adobes, and their variation with density, through a comparative study of the literature and experimental results. The literature data presented in this paper have been taken from national earth construction-related standards and normative documents, technical documents, and scientific research studies. The experimental research includes measurements of the thermal properties of six adobe test samples produced in the lab using different types and proportions of fiber additives. Through this study it is demonstrated that adobes may need further improvements in terms of thermal insulation capacity to meet the current Cyprus thermal building regulations. A deeper understanding and further research on the dynamic thermal characteristics of earth-based materials, however, are needed in order to achieve a more accurate evaluation of the thermal performance of earthen buildings. Research results further indicate that the thermal properties of earth-based materials are highly correlated to their density. By altering density accordingly, the heat storage and insulating capacity of adobes can be “manipulated” in order to achieve compliance with national thermal regulations.