Q.killing a tree by the root
How can I kill a tree by the root that has grown under my house without killing all the trees? Just the one with the 10″ round root that has grown under and out the north side of my house. I think the culprit is one of the cottonwoods growing in the creek just to the east of the house! I am quite sure that is the one, but don’t want to kill the rest. I could girdle it, but what if it’s the wrong one! I wish there was something I could put on the root that the tree that would suck it up and just kill that one. Joyce

You may want to have the trees and roots inspected by a professional arborist or tree professional to determine the best approach to this matter.
Here is a link with more information.