三合土

• In addition , exterior walls plastered with cement in the 1970s and tiles in the 1980s are susceptible to erosion by polluted rainwater ; a layer of protective paint must be added to prevent serious cracks from forming in the cement and tiles from falling . building design must move with the times and improve upon past standards
  此外，七十年代的清水三合土外墙设计及八十年代的纸皮石外墙设计，不能应付空气污染的雨水浸蚀，必须添加油漆保护层，以防止石屎爆裂及纸皮石剥落等严重问题，楼宇设计是因时制宜，以免重蹈覆辙。