Safety diagnosis through the surface inspection of existing buildings is a crucial fundamental inspection. However, the assessment results often differ depending on the investigator’s knowledge and experience, which poses challenges in ensuring the reliability and objectivity of the evaluation results. To address this issue, a preliminary assessment method for structural performance (PAMSP) of an RC Rahmen structure building was developed in this study to evaluate three surface survey items (cracks, horizontal deflections, and vertical deflections), which have a significant influence on the structural performance evaluation of buildings. The PAMSP can be operated based on point cloud data generated during the scan-to-building information modeling (BIM) process. Based on the results of two case studies, the PAMSP was found to be excellent in terms of accuracy, applicability, and ease of use. In conclusion, by using the PAMSP, it is expected that the fundamental structural performance of a building can be measured more objectively and reliably based on the data generated during the scan-to-BIM process, which is widely used in the digitization of existing buildings.