There is an increase in the middle income class in the tropical cities of the global south. Which has lead governments to focus on the provision of sustainable housing stocks. The design of these houses is a concern as they are often designed to maximize occupancy. Based on analysis of existing building design, the standard midrise buildings of Indonesia and Mumbai, India consists of double-loaded buildings to optimize the spaces. In such double-loaded buildings, the occupants living on the leeward side of the building may encounter poor cross-ventilation. This study aims to determine the optimum void design allowing sufficient cross-ventilation in naturally ventilated multi-story buildings. Computational Fluid Dynamics (CFD) is used to study the ventilation effect of voids with different sizes, windcatcher, and window size. CFD simulations are validated with the help of a Wind Tunnel Experiment (WTE). The results conclude that the provision of a void can increase natural ventilation in the leeward units of the building. The smallest void size showed the highest wind velocities. Provision of windcatcher and bigger-sized window further increased the natural ventilation on the leeward units of the building.