Frank, Those are called "BYPASS" doors and if you don't need full width access you would do fine with them. Besides unless you do the header thing you have a central obstrution anyway so nothing to gain from all the structure required to make doors that butt neatly in the center as you still can't put anything over 1/2 the width through there.

My tractor shed on the side of my garage/shop is 21X48 arranged as 4 bays of 12 ft width each. It is all open on one side except for the red iron columns between each bay and at both ends. If/when I put doors on the open side I will probably use two overhead tracks and 4 doors (again the bypass door arrangement.) This will allow simultaneous access to any two of the bays. Good enough for me.

If you don't put the "cars", wheeled roller supports, at the ends of the top of the doors but instead bring them in a ways the door will open wider without having to extend the overhead track. You wouldn't need to move both cars in, just the one that would be to the outside. Even 10-20% will open up the door way clearance dimension nicely. To take full advantage of this you would want to incorporate a header and move the center pole off to one side by the ammount the door can "over travel" with its car offset.

Brief recap: Both doors have one car brought in toward the center of its door by a few feet. If this were say the north side, it would be the north side car for both doors so they would both be slid the same way when opening for max passage width. The central post needs to be relocated the same distance to one side (toward the north in this example) and modifications to the structure (most likely a header but not the only way) to allow the offset post to take the load properly)

This gives you a significantly wider than 1/2 the opening for max width in the door clearance. and doesn't require any additional construction to support longer tracks. You do have to move the center post to one side and do al little extra work to transfer the loading.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]