hI. We just put on a new addition 2 yrs ago. The contractor we used has been in the business for over 25 yrs, and he is very good. We added on a 40 by 32 room, one and half stories. The attic is very well insulated, the structure was very well strengthened. The ceiling in the living room is drywall with a light stucco design. Very happy until last summer. We noticed a crack going the entire length of the room in the ceiling. Come winter time the ceiling would close and you couldn't even see it. Now , summer, it is back. My husband tried redoing the stucco in the crack which made it worse as far as noticeable. I hate this so much. My husband seems to think that it is because we have a humongous cottonwood tree that has very large roots that run under our house. But the older additon is 70 years old and no crack anywhere on the ceiling. He wants to cut down the tree. I am adamant about leaving this beautiful tree , it is 125 yrs old and shades our home and plants. he says it is the only thing that could be causing this.. I think that if it was the tree roots doing this, the crack wouldn't close up and then reopen other times. Please help, I do not want to lose my tree. We had a concrete company pour our foundation, and inspector walked upstairs and he said it was so sturdy that you could not budge the floor at all. So I don't know what is going on. We have no water leaks or anything. The whole house has been completely remodeled. The addition where the crack is does have crown moulding, just to let you know , although I find it hard to believe that , that would have anything to do with the crack. My husband is determined to cut down this wonderful tree. Please help.