Background Despite there is no recommendations for assessing symptoms of sick building syndrome, the use of visual analog scales (VAS) seems attractive and appropriate. We aimed to demonstrate the benefits of using VAS for evaluating subjective symptoms of sick building syndrome. Method We compared an exposed group to a control group with a one-year follow-up. To assess chronology of symptoms, employees were asked to complete four VAS at different times: after vacations (time 1), beginning of the week—beginning of the day (time 2), beginning of the week—end of the day (time 3), and end of the week—end of the day (time 4). Measurements were repeated before and after ventilation work for the exposed group and at the same time in the control group without intervention. Confounding factors were assessed. Results We included 36 employees (21 in the exposed group and 15 in the control group). Both groups were comparable. Prior to ventilation work, the exposed group had more subjective symptoms than the control group with a chronology of symptoms. After ventilation work, symptoms did not differ between groups, and most symptoms decreased within the exposed group. Practical Implication The use of VAS provided reliable data for assessing sick building syndrome and showed a dose-response relationship between occupational exposure and symptoms.