Abstract: Keongan is a kind of roof ventilation usually used in indonesian local houses. In a humid tropical climate, in general, the building is designed with natural ventilation system that maximizes the speed of wind in order to cooling the building structure or reach the achievement of physiological comfort. Some of the building design features in a tropical climate, such as the existence of wide openings, roofs with a slope angle, have a plafond, and maximizing the shades around the building. The density of buildings is one of the factors which affect the principle of micro-climatic conditions and determine the conditions of ventilation and air temperature. Heat symptoms in main cities affected by urban density rather than the size of the city itself, the more dense, the worse the condition of the building ventilation. Architecture of buildings, tried to adapt to the nature and tried to blend with nature. Norms, customs, climate, culture, beliefs and local materials will be given its own color in the development of vernacular architecture. The long journey through trial and error with the local genius, is capable to displaying it’s identity. Several features of houses in Semarang Village include : symmetrical floorplans extends to the rear, circulation straight from front to rear, limasan roof or saddle roof, three openings (doors) on the facade, door consists of two doors, Ornaments eaves (lisplank) on the front facade, the Consul made of iron or wood with the formation of ornamentation, Ornaments on bouven above the door. The results of this study, the shape of gable roofs are part keongan utilized for the air stream that is useful to cool the hot air under the roof at once will lower the temperature in the house. Roof ventilation in Semarang houses mainly applied keongan and openings in the ceiling to circulate the hot air out of the building. Roof ventilation in the form of air cushion roof due to the formation of a high roof space. High roof shape with a roof ve