Metal is one of the building materials which is used as structural framework for larger buildings such as skyscrapers in Plymouth. It is also used as an external surface covering. There are various types of metals used for building purpose as per the requirement. The major component of steel is iron, and it is the usual choice for metal structural building in Plymouth. The reason for which it is chosen is its strength, flexibility, and if refined well lasts for a long time. Corrosion is metal's prime opponent when it comes to matter of longevity. Chrome, gold, and silver are used for decoration purpose, since these materials are quite expensive and also lack structural qualities such as tensile strength and hardness.