Dado rails, sometimes referred to as chair rails, sometimes called panelling, and often times called wainscoting, were originally designed and installed to protect walls from scuff marks.
They are now used as interior design decorative pieces. They can go around the perimeter of a room, or they can be used to make square or rectangular shapes on walls. These shapes are known as wainscoting.
They are typically installed to add an elegant touch to the interior design of a home, as well as to protect the walls from damage. They also add depth and a layer of interest to sometimes bland or plain walls.
They range in materials they are manufactiured from, from wood, EPS polystyrene, XPS polystyrene, polyurethane (PU), ultra high density polystyrene, and now we even have polymer dado rails.