@hergalope, A standard 6'-8" door is the door slab measurement itself. By the time you add a threshold, the jamb, and some room above the door, the framed rough opening is 6'-10.5" to 6'-11". In the case of the sliding door, the rough opening is 6'-8" and the glass panel is not. All the swinging doors, both interior and exterior, are at the taller height that the windows are set at (unless the door comes from a window company, ironically), and that is what most people refer to as standard. I am not sure why some people refer to what is known as a 6'-8" slider as "standard" anymore, but I believe the actual door blank was at one time that size. That is back when the bottom track was paper thin and the upper track fit over the door, not adding much height either. At that point, the rough opening height would have been more like 6'-9", but still lower than a standard hinged door with a jamb is. What they call a 6'-11" sliding door is actually closer to standard in relation to interior doors.
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