Hi. I live in a house that is over 100 years old. Earlier this month, a friend of ours was looking at a new bladder tank we had purchased for our well, and he noticed that we had a major problem with the floor joists. He showed us that many of the joists that support the center of our house, and the outside walls are litterlay falling aprart. Some are cracked, some look like they have been eaten by termites, although I have not seen any, and some look like they have just dried up, and withered. There are about 10 of them like this, and it looks like the previous owners tried to fix it, as there are about 8 or 10 jacks in various spots throught the basement. I can notice upstairs that the floors are sagging toward the middle, and am not sure how to go about fixing it. Please advise. Thanks.