New addition settleing - crack in foundation
We added on to our house 530 sq ft 17 years ago, the house was then 16 years old. The walls which attach to the older house (at a 90 degree angle) show about a 1 inch shift. The taped sheet rock is twisted or shifted showing the new addition has settled down. You can also feel in the concrete floor going from the old part of the house to the new addition a downward bump. Also in one of the new rooms you can feel under the carpet an unlevel area indicating there is a crack with one part sinking more than the other. In the attached bathroom we have ceramic tile and it has a crack which during the spring/summer can be as much as 1/8 to 1/4 inch wide but during the late fall/winter shrinks to a hairline (actually looks like a long hair lying on the floor.)
What do you suggest we should do for this problem. We are looking at putting the house up for sale. I know we need to repair the sheet rock and paint. Do you think the foundation issue is something that needs addressing or is this a normal thing and I should not worry about it? Also we do have three large trees near the new addition (within 6 feet). Should we have these taken down? Do you think they are causing the problem and if we take them down do you think the problem could get worse?