The erosion of adobe heritage under the influence of natural factors, especially rainfall and humidity, is one of the most important challenges in the conservation of this heritage today. Alongside traditional options for the protection of adobe heritage, such as the use of straw plaster, in recent years, various chemical products have been marketed for the protection of building materials and components, especially against the threat of moisture, and consequently, serious tendencies have been expressed in the field of evaluating these materials in the field of conservation and restoration. Therefore, the scientific evaluation of the properties of these materials seems necessary for their judicious use. Since many of the chemical materials available in the market are mainly designed for the protection of stone and brick, it seemed necessary to conduct this study in order to protect adobe materials and optimize the penetration of these materials into the adobe texture. In this research, considering the need to increase the resistance of adobes against moisture, the hydrophobic properties of four different commercial products with the names of Stain Repellent AKEMI, SRP130, PTS+ and Long Life, were evaluated and compared with each other on the structure
of adobes. The results of the research showed that although all the commercial materials studied provide the possibility of significantly increasing the resistance of adobe against moisture, the Long-Life material has a higher ability to penetrate and hydrophobize adobes compared to other chemical products. This issue can significantly increase the surface resistance of the adobe against both long-term contact with moisture and against mechanical erosion factors. The results of this research can be used as a basis for future studies in the direction of localizing chemical materials for the protection of adobe works and optimizing their application in the conservation and restoration of adobe historical buildings.