As populations expand around the world, the pressure to build upwards is growing. In cities such as New York, adding floors to a building is commonplace, while in Hong Kong thousands of rooftop extensions are added illegally. In Britain, the practice is less usual but it may become more so in future, as a less disruptive alternative to basement excavations. John Parsons, associate director of built environment at the Royal Institution of Chartered Surveyors, says: “If you want to extend in a sensitive area, then this is the way to do it.”
隨著世界人口的不斷膨脹，蓋高層建築的壓力也與日俱增。在紐約這樣的城市，在原有的建築上加蓋樓層司空見慣，而在香港，成千上萬的屋頂加蓋了違章房屋。而在英國，這種做法並不常見，但將來它作爲破壞較大的開挖地下室的替代方案，也會越來越普遍。英國皇家特許測量師學會(Royal Institution of Chartered Surveyors) 負責建築環境的副主任約翰•帕森斯(John Parsons)說：「如果想在敏感地段拓展居住空間，那麼這就是應對之策。」