Old materials and techniques to improve the durability of earth buildings

Abstract

Quite a big part of the world’s heritage is still made by earth constructions. The durability of the existent heritage, as well as the new earth buildings is particularly conditioned by erosion caused by water action, especially in countries with high rainfall index. With this research one intends to value the ancient knowledge in order to allow higher durability. Analysing the old building techniques to protect the earth material from the water action it is possible to understand how earth buildings were preserved, during several centuries, resisting to harsh weather conditions. Among these techniques, one can observe the incorporation of biopolymers (such as oils or fats of animal or vegetable origin), the addition of some minerals and the stabilization with lime. However, this ancient knowledge seems to have been forgotten, probably due to the existing prejudice concerning earth building which is often associated with a poor construction. This research aims, also, the study of new methods of soil stabilization, with lime and biopolymers, adapting the ancient knowledge to improve the durability related to the water action. This way, alternative solutions were obtained in order to improve the performance of earth buildings in terms of resistance, especially when in contact with water, reducing the water permeability and keeping the vapour permeability of the material, one of the main advantages of earth construction.