Abstract
Earth is the most common and important building material used in the construction industry, since it is found in almost every country in the world. Modern earthen construction is alive and well, and is spread over an enormous geographical area. This technique utilizes various earthen materials and numerous methods, and features many benefits for both construction in general and buildings in particular. Najran, a city located in the south of Saudi Arabia, is distinguished by its heritage of earthen architecture, which displays many advantages and a marvelous variety of types and exterior designs. Many weaknesses of the material, however, along with a lack of knowledge and rapid development have caused the uplifting and destruction of many of Najran's mud and heritage buildings during the last few generations. Not all soil types are suitable for every building need. Soil specification is thus very important in order to ensure that the materials used in construction meet all requirements. The main goal of this study was to invistegate the suitability of local soils for the earthen building construction. Thus, available local materials of common quality were taken from local sites in Najran. Laboratory experimentation and testing was then performed to determine the properties of those materials. The results showed that local soil properties are suitable for using in the earthen block construction since they satisified the specifications. The results were then recorded for use in further studies, as well as to explore heritage building and rehabilitation, and to improve modern earthen building materials and techniques.