Stack Back is knowing how many inches a drapery is going to take up when it is completely opened, or ‘stacked,’ back to the furthest extent the hardware rod will allow.
Stack Back width depends on whether the drape is a one-way draw or center open and what the overall rod width is. Once you have these two key bits of information, solve a simple formula.
Rod Width ÷ 5 = Stack Back Per Side
ONE WAY DRAW
Rod Width ÷ 2.5 = Stack