Slopping Floor – What should I Do?

Q: We just bought a home built in 1950 and we just notice that our second floor is slopping and I would love to put new floors down so i would like to know what would be the first thing for me to do.
A: First off, you need to determine how severe the slope is and if the slope is even across the floor. Figure out how much the floor’s height changes and the length at which this change occurs (for instance, if it changes 1/4″ over 10ft etc). Also, find out if this slope is even across the floor – so if your slope runs East to West, make sure the floor’s slope is even North to South.
Once you determine this, its dependent on how extreme the slope is. If the slope is something you notice and are unhappy with, don’t patch it. If you are going to fix this, fix it the right way. My guess is that the slope runs to an exterior wall here. Find the offending wall, then head down stairs along the same wall, and investigate at the bottom. If you find the same slope on this wall as well (which is likely you should) then there is a fairly simple and inexpensive repair which will fix everything properly.
What you will need to do is figure out how much you will need to adjust the wall in order to get the floor level, then get a post or some proper shim and some screw jacks meant for lifting floor joists. Jack up the floor joists using a support beam to the proper height, then unbolt the plate, install your shim/post and rebolt the plate. From here you are all set and the repair is done properly rather than a simple patch covering up the problem.
Now if you slope is very slight, say 1/4″ over 15 feet or more, then could very well install right over the top of it, but it will not repair the slope. This is very dependent on the installation type. Floating floors will have little problem installing over a slight slope, but glue down or nail down applications will have a bit more trouble.
In the end, if you are unhappy with the slope, fix it the right way, but make sure you take your time when doing it and get it done right.