"tong lau" (cantonese) or "tang lou" (mandarin) means "chinese building" – "tong" or "tang" (唐) refers to the tang dynasty and is used as a term to mean chinese, and "lau" or "lou" (樓) is a building with more than one floor. it is a general term for a type of building found in hong kong that also developed in macao and guangzhou from traditional southern chinese townhouses. the early buildings were generally long and narrow with width of between 12–15 feet determined by the length of the wooden beams. in hong kong's building regulations, it refers a building with any living space intended for more than one tenant. it is essentially a tenement building for residential and commercial use. the ground floor is reserved for commercial use, mostly by small businesses like retail shops and food vendors. the upper floors were residential use and catered to chinese residents of hong kong. most early "tong lau" were 2–4 storeys tall because building regulations that initially limited the height of building to 1.25 times the width of the street with a maximum height of 35 feet. however, due to the influx of migrants from mainland china to hong kong in the 1950s, height control of buildings was relaxed in 1955, and some "tong laus" that were built after that may have 9 or more floors, and built without lifts. the heyday of "tong lau" ended in the 1960s when population pressure resulted in many "tong laus" being demolished to make way for high-rise buildings and changes in building ordinance that allow for such high-rise buildings.