That is quite a large area for the floor to have dropped but if the drop is 3 4 to 1 inch deep i don t think it is a big problem and you and your wife can breathe easy.
Floor slants 1 4 inch.
Nearly all will say that if a floor slopes 1 and 1 2 inches in twenty feet or more that there should be further investigation.
Basically they are saying if a floor is sloping over a 1 2 to 1 inch in twenty feet then there is concern.
For rooms that have a general slope the issue may be foundation problems that require the assistance of a.
Mix up some concrete mix in the mixer.
Your probably best leaving yourself about 1 4 inch and adding a bit more adhesive at the entry if necessary.
To replace a shade for a floor lamp consider that floor lamp shades need to generally be larger due to the height of the lamp.
Install plywood subfloor.
Consider also the style of your lamp whether it looks modern or more traditional.
A slant slope situation might be one where over the course of 15 or 20 horizontal feet the floor slopes down one or two inches.
But you can always bring things up rather take away material.
Use a router with a 1 4 inch roundover bit to round it significantly.
Follow this by a strip of 1 2 inch plywood at the 1 2 inch mark a strip of 3 4 inch plywood at the 3 4 inch mark and two layered strips of 1 2 inch plywood at the 1 inch mark.
The curvature of the lip is a matter of personal choice.
Mark this outer height mark along the wall with a pencil.
If the floor slants irregularly cut strips that bridge the cap at each floor joist.
Use an orbital sander with 100 grit sandpaper to round it lightly.
Lamp shades for floor lamps.
Screw the strips into the floor joists or subfloor.
Floors that slope 2 or 3 inches in 20 feet would be a very serious concern.
Probably more like 1 8 3 16.
For example a floor that extends 4 feet away from the drain should have 1 inch of overall slope.
Often floor lampshades are in the range of 16 to 20 or more width.
Except for that slope the floor itself might be flat.
Use a belt sander with 100 grit belt to round it to a higher degree.
Floor slopes and slants are common in old houses.