Air-conditioning is commonly used to achieve thermal comfort for commercial buildings in the hot and humid climates. This practice accounts for nearly 60% of total electricity consumption in a building. The passive system is a way of integrating interventions with the capability to be operated by itself with minimum interference of manmade fossil-based energy such as electricity. The paper used a case study approach to understand the sectional adaptations for passive climatic modifications in Sri Lankan Non-domestic Architecture. Three case studies were selected by considering the use of passive climatic modification systems such as thermal mass, natural ventilation, daylighting techniques etc. Buildings were selected from an urban context with similar activities and the interplay between the "Man and the Building" was considered as an important part of designing passive climatic modification system. All three case studies have similar building material pallets such as brick and masonry building systems and a roof is a steel section with lightweight building system. Use of passive interventions can contribute to modifying outdoor climate into a favourable indoor condition. However, thermal investigation of selected case studies found that having passive systems alone do not make a comfortable indoor climate due to problems with building design. These buildings are found to be supported with a contribution from active system control in maintaining indoor climate within comfort ranges. The outcome may be useful in designing non-domestic buildings in Sri Lanka. Therefore the certain amount of studies should have done in order to incorporate passive climatic modifications and active climatic modifications in the hot humid climatic condition like Sri Lanka especially for non-domestic functions such as institutes etc.