Measuring door sag.

[Bod]

I have a door to stop sticking.
Wooden frame and lower 1/4 panel, the main in-fill is 2 panes of laminated glass, running from top to bottom.
The door is maybe 15-20 years old, and has a history of sticking, mainly along the bottom.
My feeling is the glass is too heavy for the frame, and the door is falling out of square.
Measuring the diagonals will only show how much has been "removed" by past attempts to un stick.
Would putting a Square in to the corners of the glass frame, give a reasonable indication of the doors squareness?
I suppose that large right-angle repair brackets at each corner will be the low cost remedy. Applied to both sides.

Any further ideas?

Thanks
Bod

 

[Doug71]

Can you measure corner to corner of the glazed area, that will tell you if it has sagged or not? Same as using a square in the corner as you mentioned but more accurate.

The traditional/easier way of checking internal corner to corner is using pencil marks on a lath rather then measuring or if you want to be really clever put a pin in one end of the lath then push that in to the corner then you only need to mark one end if that makes sense?

 

[Sandyn]

I use a digital angle finder on all corners of the door and frame and measure lengths as well. It's much easier to see what's wrong.
If I have a sagging door, I prefer to remove it, get it flat to relieve the problem for fixing. I look for the tenons and strengthen with a number of screws. If there are wedges, I might force in a new wedge, if the door looks strong enough. I do this with windows as well. Just need to be careful not to crack the glass if banging with the hammer.