This guide will help you identify which dimension refer to which part of a dado or picture rail.
Each rail has three dimensions which will need to be specified. These are the: height, width and thickness/depth of the rail. This is made slightly easier on this product since these products only come in limited sizes.
A dado rail or picture rail will normally be either thinner or the same thickness than the architrave that it will butt up against, please bear this in mind if you are seeking to use these with 15mm thick architrave.
Dado and Picture Rail Dimensions
Height: This is how tall the rail will be, when measured from the top to the bottom edge.
Width: This is what the block measures from the left edge to the right edge.
Thickness: This is how thick/deep the block will be measuring from the back edge to the front edge, or from the wall outwards. Plinth blocks and rosettes usually thicker than their surrounding mouldings by as much as 7mm or as little as 3mm, which allows them to stand pround.