The Florida Public Hurricane Loss Model (FPHLM) is a public catastrophe model operating in the state of Florida. This paper presents a novel modular approach used in the FPHLM to assess the vulnerability of mid/high-rise buildings (MHRB). The approach combines estimates of existing building defects with the probabilistic simulation of building envelope wind damage and accumulated horizontally impinging rain to predict the amount of water that enters a mid/high-rise building during a hurricane. The approach discretizes each building into typical apartment units, assesses separately their exterior damage due to wind and debris impact, their interior damage due to water intrusion and then aggregates the damage from each apartment to estimate the overall building vulnerability, taking into account water propagation from floor to floor. The MHRB vulnerability depends on the wind profile that the building experiences over its height for a given synthetic or historical hurricane and the associated rain prediction.