We are about to begin renovating a two-story house built in 1930 (according to tax records, anyhow). It has a noticeable hump in the floor that is present in the same place on both the 1st and 2nd floors. Upon further investigation, we found that there are shims above the floor joists directly beneath the rise in the floor. Our best guess is that the floors were shimmed up to meet the fireplace hearths, which are raised a bit (the shims are on either side of the hearth, underneath the hearth/floor transition).

So my question is, would lowering the rise in the floor be a simple issue of raising the floor enough to remove the shims, then lowering it back down? Or is there some compelling reason not to do this? Have any of you encountered something similar?