A casing or rod pocket is the hem along the upper edge of the curtain or valance. The curtain rod is inserted through the casing so that the fullness of the curtain falls into soft gathers. Before cutting the curtains, decide on the casing style. A simple casing places the curtain rod at the uppermost edge of the curtain. For simple casings, add to the cut length an amount equal to the diameter of the rod plus ½’’’ (1.3 cm) to turn under and ¼’’ to I” (6 mm to 2.5 cm) ease. The amount of ease depends on the size of the rod and thickness of the fabric. A heading is a gathered edge above the casing. It finishes the curtain more decoratively than a simple casing. Curtains with headings do not require cornices or valances. For casings with headings, use the formula for a simple casing, adding to it an amount twice the depth of the heading. Headings may be from 1″ to 5″ (2.5 to 12.5 cm) deep. The depth of the heading must be determined before the curtains are cut. The heading depth should be appropriate for the length of the curtain: in general, the longer the curtain, the deeper the heading. Wooden, brass or plastic poles may be covered with a shirred pole cover. The exposed pole between the curtain panels is covered with a casing made from a shirred tube of matching fabric (above). The casing may be plain or have a heading the same height as the curtain heading. Wide poles and casings are more than decorative. They often are used to conceal a shade heading, the plain heading on shirred curtains, or the traverse rod of sheer or lightweight curtains. Wide casings are used on the flat Continental rod or cornice rod. These rods are 4-1/2” (11.5 cm) wide. A cornice rod is actually two regular curtain rods attached with a spacer between them. Finish lower and side hems of curtains before sewing casings and headings.

{Credit} Singer Sewing for the Home Copyright 1984-1988