A.Finish carpenter Dave Frane responds: The upper half of a Dutch door can be operated without opening the lower half. Dutch doors are often seen in barns and greenhouses, but they are also used by people who want to open part of a door without allowing pets or small children to get in or out of the room.
Odds are it's cheaper to buy a ready-made Dutch door than to convert an existing panel on site. But if for some reason you have to convert an existing door, first you'll need to figure out where to split the door. The passage set goes in the lower half, so you should cut the door a couple of inches above the knob. You'll need to trim about 3/4...
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