The determining factor in how high or how wide you want to go is just how much you want your sliding door to overlap with the opening.
Interior barn door opening overlap detail.
If you want it to completely cover your overhead door trim you ll have to measure from the top of that down instead of just inside the door.
In this application the doors overlap and slide over one another so that half of the opening is accessible at any time.
You will cut your slats exactly the height of your opening minus whatever clearance you want the door to have above the floor i wanted mine to have 1 2 inch between the floor and the door.
There must be a support beam or strong studs in place on which to anchor the sliding track and there should be ample space between the top of the opening and the ceiling to install the track.
Add 1 to 2 per door for overlap depending on privacy needs.
Your door s width should be 2 to 3 inches wider than the door opening and 1 inch higher than the dimensions of your opening.
To have privacy the door usually overlaps the opening by an inch so that a 2 6 opening will require a 2 8 door.
This means on one side of the door opening or the other there should be at least 2 8 and perhaps a little more to ensure all the hardware can fit properly.
Measure across for the width and from the top of the casing molding to the floor for height.
This application is great for areas where barn doors are desired but there isn t adequate room on either side of the opening for the door to slide.
The final option is bypass doors.