For generations, natural ventilation is the most efficient passive strategy for regulating the indoor temperature, hence providing healthy indoor environment. However, in contemporary architecture, natural ventilation is not being exploited to its maximum potential, particularly in multi-storey landed houses. The efficacy of natural ventilation can be affected by a number of factors, especially façade treatments such as balconies. As balconies have been extensively introduced into dwellings for a variety of functions, nevertheless, the provision of a balcony as a passive design solution to improve natural ventilation is not among them. Moreover, a building with a deep layout plan such as terrace houses, in particular, a single-sided ventilation strategy is inevitable, resulting in a substantially reduced ventilation efficiency compared to a cross-ventilation strategy. Consequently, the performance of balcony ventilation can be significantly improved by incorporating wing walls into balcony design, since wing walls are an effective facade treatment for increasing the ventilation flow rate of single-sided openings. The initial aims of this study is to identify balcony design that perceives unsteady airflow performance through structured observation on the existing balconies of double-storey terrace houses within Taman A, Malacca. This method was executed in order to achieve the research objective which is, to identify the existing balcony design of double-story terrace houses that may experience unstable natural ventilation performance. Hence from the observation, open balcony that received parallel wind were established as a balcony that perceived to experience unstable natural ventilation. The future aims of this research therefore is to establish where the provision of wing wall in balcony is a feasible facade design method for improving indoor ventilation and significantly reducing energy consumption in buildings.