A stiffening; such as a strip of crinoline or buckram is used at the top to support the pleats.
For Lined Draperies—To length measurement, add 1″ for heading, 4″ for hem and 3½″ for bottom hem.
Example—If length from top of rod is 90″, add 1″ plus 4″ plus 3½″. This equals 98½″ for one length, or 5½ yards for the two lengths.
For Unlined Draperies—To length measurement, add 1″ for heading, 4½″ for top hem and seam, and 3½″ for lower hem. A 4″ wide strip of crinoline is used at the top of both lined and unlined drapes.
If a double hem is used at the bottom, then add 6″ instead of 3½″ for hem in either lined or unlined drapes.
For Interlined Draperies—To length measurement, add 1″ for heading, 3″ for top hem and 3″ for bottom hem.
When using ready-made headings for pleats, add to the length measurement 1½″ for heading and seam, and 3½″ for bottom hem.
French Doors or Window
The rod should be placed so that the drapery, when hung, covers the glass portion of the window. Take measurement from top of upper rod to lower part of lower rod. To this measurement, add 2½″ at the top and 2½″ at the bottom. This allows for a 1½″ hem, top and bottom, plus ¼″ seam allowance. The 1½″ hem is for a ¾″ casing and ¾″ heading.