When conceiving the project of a building, we understand that it will be interacting with the ground through a "soil-structure" system, and that it will be the appropriate interaction between the ground and the foundation that will guarantee functionality and stability from the geotechnical perspective as structural of the project. Today we identify buildings that present problems concerning structural stability due to a deficient geotechnical study that entails a negative impact from the point of view of safety, functionality and economics of the project. The professional in charge to determine the geotechnical conditions of a site is the Geotechnical Engineer or Engineer specializing in Soil Mechanics, in fact, it must be a professional with comprehensive training with knowledge in various disciplines such as geotechnics, structures, foundations and construction. The document with which we base ourselves to establish the guidelines to follow from an analysis and design perspective is the geotechnical study. This document also allows us to understand the possible threats to which the project will be at some point and how to carry out the analysis and design of the buildings, so that they can interact in perfect harmony with their surroundings. By means of a case study concerning the project of a sustainable rural house, we show the stages and elements that make up the report of the geotechnical study that was carried out, indicating the development, analysis and methodology of the study, as well as the various elements that comprise it.