My old 3-unit condo has a nice old wooden entry door, with 3 horizontal rails and 2 vertical stiles, with a single large pane of beveled glass as the top panel. The door is very similar to the one shown below.
Over time, this door has become racked, i.e. not square; the latch side is sagging below the hinge side. At one point, it appears that someone shortened the door, attached a triangular filler strip at the top and re-hung the door to get it to fit in the still-square doorframe.
It appears the sagging has not stopped, as the bottom of the door is beginning to scrape the threshold, and I've snugged all the hinges. The stiles and rails seem to have a little play in their joints, i'm pretty sure this is where the sagging is coming from.
How can I re-square this door, or at least stop the racking from getting any worse?
I don't want to mount a big ugly turnbuckle on the door--the reason for keeping the old door is primarily aesthetic, rather than cost-related.