Earlier metal roofing was sheeting in the form of corrugated galvanized steel and is still found today in parts of the developing world. In addition, colour-coated steel roofs are popular in some of the Nordic countries such as Finland and Sweden.
Modern windows are usually glazed or covered in transparent or translucent material. Most glazed windows may be opened, to allow ventilation; or closed, to exclude inclement weather. They are held in place by frames.