I have a breakfast nook that is sagging about a quarter to a half an inch out of square particularly on the left side facing the nook on the outside of the house. What is the simplest way to jack up and stabilize this minor drop prior to replacing the windows in the nook?
check the sill plates and floor beams to see if there is any rot or termite damage.
If you could post a picture we will be able to help you better, there could be something going on ,on the left side. BOB