Stackback

Stackback is the width (or height) a window covering takes up when it’s fully opened out of the way — the bundle of vertical vanes pushed to one side, the stack of panels parked beside a slider, or drapery gathered at the ends of a rod. It matters because it eats into your view and your glass: underestimate it and an “open” covering still blocks part of the window or, worse, part of a doorway. For sliders and wide windows, check the seller’s stackback figure and, where possible, mount wide enough (a wall extension beside the opening) so the covering clears the glass when open.