Prefabricated bay window and building structure thereof

According to the prefabricated bay window disclosed in the first aspect, the end face connecting rib is arranged on the upper end face of at least one of the left side plate and the right side plate. When one side of the prefabricated bay window is installed close to an upper-layer balcony, the end face connecting ribs can be inserted into the upper-layer cantilever beam from the bottom, and therefore the corresponding side plates are located below the upper-layer cantilever beam and connected with the upper-layer cantilever beam into a whole. Therefore, the width of the bay window can increase the thickness of at least one side plate, and the effective use space of a building is increased. According to the building structure of the prefabricated bay window in the second aspect, the prefabricated bay window in the first aspect is adopted, and the effective use space of a building is increased. 本申请第一方面公开的预制凸窗，在左侧板和右侧板中至少一个的上端端面设置端面连接筋。该预制凸窗一侧紧邻上层阳台安装时，端面连接筋可以自底部插入上层挑出梁，从而对应的侧板位于上层挑出梁下方并与之连接为一体。所以，凸窗宽度可增加至少一个侧板