Wooden down legs are added to board mounted window treatments to make the side rigid.  You need to add a minimum of 2″ to the window casing’s outside width so that the legs clear the casing on both sides.

Fabric on most products runs north to south (top to bottom).  Railroaded fabric runs east to west (left to right).  On specific products  like this railroaded fabric cornice and fabrics such as solids, the workroom will railroad the fabric to eliminate seams. On flat valances and window treatments if you can have the fabric railroaded it is the way to go.  Remember that this only applies for valances that over 45″ wide.  If you are under 45″ you will not have to worry about vertical seams since fabric is generally 54″ wide off the bolt.

When making a valance that is mounted on a board, you will have to take into consideration the thickness of the actual board under the fabric.  The window treatment is made with wood “legs” on the sides.  The wood legs make the inside measurement approximately 2″ narrower than the face width. When Valance measuring, please refer to picture below.  This is very important if you are tight on room around your casing.

Please add a minimum of 2″ to your ordered width so that your legs easily clear the window casing (molding) when installed.