Author(s)

E. Hamard, J. C. Morel, F. Salgado, A. Marcom & N. Meunier

Abstract

As part of a working definition of a new code of practice, a methodology is being defined to determine the suitability of plasters manufactured on-site to protect earthen wall of vernacular architecture buildings. Given the diversity of raw earth construction methods, ranging from massive earth to stone masonry with earth mortars, and the variability of the materials used, it was proposed two on-site testing: a shrinkage test followed by a shear test. These tests, as well as additional tests, were performed on an earthen wall using two different earth plasters. This first testing campaign has permitted to validate the on-site shrinkage test but not the on-site shear test. A future testing campaign will explore the influence of various parameters on the shear test. Keywords: earth plaster, earthen vernacular architecture, durability, on-site coating testing. 1 Introduction Historic earthen buildings represent an important, though difficult to quantify, part of the human habitat worldwide. In France, according to Michel and Poudru [1], in 1987 there were approximately one million earth houses (rammed earth, adobe and cob) with average ages of 100 years. All of them have more than 50 years old. This heritage ought to be preserved. One of the major issues is the repair of their protective plasters. Unfortunately, old construction techniques fell into disuse in the West and are therefore no longer controlled by the vast majority of today masons. Industrial ready-to-use coatings are unsuitable and even harmful to earth constructions [2, 3]. As part of a working definition of a new code of practice for plaster implementing on earthen walls, we conducted a

Keywords

earth plaster, earthen vernacular architecture, durability, on-site coating testing