Double-width curtains are created by combining two fabric widths to cover larger windows. This results in a seam where the fabrics are joined, known as a splice-up. It's necessary because standard fabric rolls aren't wide enough to achieve the full width without this seam, ensuring the curtains fit larger windows seamlessly.
For pinch pleat, tailor pleat, inverted box pleat and goblet, if the curtain finished length is over 108 inches, then the max finished curtain width without seam is 56 inches; if the curtain length is less than 108 inches, no seam for any curtain finished width. Otherwise, the width needs to be double-wide with a vertical seam.
For triple pleat and triple tailor pleat, if the curtain finished length is over 108 inches, then the max finished curtain width without seam is 50 inches; if the curtain length is less than 108 inches, no seam for any curtain finished width. Otherwise, the width needs to be double-wide with a vertical seam.