A dado rail, also know as a chair rail, is a type of moulding fixed horizontally to the wall around the perimeter of a room.
The dado rail is traditionally part of the dado and although the purpose of the dado is mainly aesthetic in modern homes, it provides the wall with protection from furniture and other contact. Traditionally, the height of the dado rail was around 900mm, which was a suitable height to protect the wall from the backs of chairs. Since the original purpose of the dado treatment is not applicable in modern homes, it is common to see dado rails at 1200mm or even 1500mm from the floor.
Dado rails are also sometimes applied to a wall without the full dado treatment. The purpose of the rail in these cases may still be protective, and it is common in environments where walls are subject to a lot of wear and tear, such as shopping centres and hospitals.