I think what you mean is a pocket door. Here's the google page to how to install pocket doors, pick a video and see what's involved.

https://www.google.com/search?q=how+to+install+pocket+door&oq=how+to+install+pocket&aqs=chrome.0.0j69i57j0l4.7619j0j4&sourceid=chrome&ie=UTF-8

If I understand correctly, there will be a uneven gap at the bottom of the door.

Yes, I guess it would be a pocket door. And yes, as it stands there would be quite a gap!

I'm looking for creative ideas that might be less costly than "fix all the floors",

Sounds like its not fixing the "floors"; its a structural issue. What is causing the slope? What kind of foundation do you have? Did you have an inspection when you purchased the house?

It's historic structural movement - the house is late 1800s/early 1900s and the survey said there were no signs of further settlement.

We had a rowhouse from 1906 and the floors had drastic shifts from one side of the house to the other, and sometimes dropped 3 inches over 4 feet. That's just wonky old houses. We had an inspection when we bought, the people who bought from us had an inspection, and we did a major addition on the back of the house and no one was at all troubled by the slopes. Everyone agreed it was not structural, was nothing to be concerned about, and was definitely not anything to waste major $$ on, unless we were terribly bothered by it. So ignore the folks above who scream "structural!"

We had to have a door that was exactly even with a major drop of 3" (from a 1940s addition where the floors never lined up properly), and we just ignored it. Our a/c unit was behind the door so it actually just added more air flow. So yes, go ahead and put in doors that go over your wonky floors. Just a charm of an old house.

There may be a way to jack up the joists, if you have crawl space, just at the area where the door will go. Other than that, I'm not aware of any trick to reduce the gap.

A pocket door sounds like your best bet, unless you can put in a door that swings into the room that slopes down.

The door that's there currently opens into the room, but we are planning to open up the wall to the right through into the new kitchen, so the door as it currently sits would be very awkward, opening round across the new thoroughfare to the kitchen. We could obviously just hinge the door on the other side but then it needs to open uphill....

A pocket door is a good solution.

Maybe saloon doors? Or some kind of barn door?

Mudroom · More Info