The lower part of a room wall, especially when denoted either by full panelling or a planted rail – which being at the top of the dado area is known as the dado rail, or chair rail. Traditional panelled walls show the division of the dado area at approx. one third of the room height. However, more accurately, the top of the dado – whether rail or panelled section – was set at the height of the top of a chair back, in order to prevent the chairs and sofas – the newly available status symbols of upholstered furniture, from rubbing against the walls, and in particular to protect fashionable and costly wallpapers or fabric walling, when the style of the day and the living set the furniture around the edges of the room.
From this the dado area came to be treated separately and is often covered with a more durable or more easily repairable finish–such as wood panelling, grass cloth, or paint, as opposed to paper or fabric that can easily mark and tear. Although considered separately in terms of material, it all usually works best when the colour is either similar, or a neutral – such as wood, or off white for example. The skirting board should be treated the same as the dado – by colour or material or both. For painted walls, where there is no joinery, the dado might instead be delineated by a band of paint between two other colours.
In any case many reasons have historically driven the need for the lower areas of the walls to be treated differently, to be more robust. Typically wooden board panelling – tongue and grooved or tongue grooved and beaded, has been used to keep damp away, battened off the wall and vented to allow air to flow to freely behind.
In classical architecture, this refers to the area between the base and the cornice of a pedestal.