Although originally designed to protect walls from damage inflicted by the backs of chairs, the chair rail today serves as a decorative function. By encircling the perimeter of a room or separating different wall finish treatments it can define the room. It is generally affixed horizontally along a wall at a height of approximately 900 to 1000mm, or at about 1/3 of the way up from the floor to ceiling. Another tip is to place your chair up against the wall, mark where it hits the wall and centring the rail at this level. Useful Porta How To Video – How to install a Chair rail/Dado rail