We recently purchased a two-story home built in 1850. After living here for a bit, we noticed that the floors are sagging quite a bit both on the first and second floors. The foundation is field stone and is partially built into a hill.
The floors are small, only about 480 square feet per floor (about 20 feet wide by 25 feet long) with one main beam running across the main floor that is exposed and has been enclosed with decorative wood. The main support in the basement is a single 6x10 about 3/4 across the beam. The basement has carpet on cement but it feels like there is a slightly raised square "stump" (for lack of a better word) in line with the existing support beam.
The main floor sags in the middle and has a definitive dip towards the outside wall. The dip appears to be a good 2 inches or so and a hairline crack is visible on the outside wall between the wall and the floor there. The main floor is open concept with no support for the existing beam crossing the space except for the outside walls.
The second floor also seems to have a main support beam but the wall underneath it was taken out to put in a closet.
After we moved in and winter set in, we noticed a lot of thin cracks from the corners of windows straight up, sometimes to the ceiling but they stop there.
We don't really care if the floor are level but it seems like the house needs to be kept from further sinking/settling. The open concept living room (which has a 70's parquet floor) seems wrong in a house like this too. I feel like there should be a support beam somewhere in there.
From the reading I've done we should consult a structural engineer but I don't know how to go about hiring one.
Oh, and to complicate things further, the sagging point in the middle seems to be a point of delineation. From the sag to the front of the house, the floors on the first floor and the basement floor are level. From the sag backwards (towards the hill) the is a slight incline that is similar to the hill. A doorway built into the fieldstone foundation on the front side of the house is perfectly level.