Abstract The modification of surfaces for the creation of hydrophobic materials has grown in recent years due to the wettability properties that can be obtained, in this process the chemical environment of the surface is modified. In the case of aluminosilicates, surfaces are generally considered polar, so it is of great interest to create hydrophobic surfaces through the functionalization process, obtaining low wettability; hydrophobicity is determined when a surface comes in contact with a drop of an organic component and contact angles greater than 90 ° are obtained. The present work describes the results of the study of the contact time between aluminosilicate surfaces and a siloxane as a functionalizing agent, to determine the optimal time in which hydrophobic surfaces are obtained. The results show that after 3 hours of contact between the surface and the functionalizing agent, a surface with a contact angle of 106° is generated, due to the heterogeneous surface of the functionalizing agent that is generated in the aluminosilicate because of the polymerization reaction.