Just got this job for installing a patio. It's about 12'x14'. The old deck was removed to get to the septic. There is a large root on one side that is about the same thickness as the depth I have to work with. If i don't remove the root it will be exposed slightly above the patio. It looks like the homeowner already cut a few feet off it. Kind of weary about cutting it back more. How far could I cut it back w/out doing any damage to the tree. Or will I damage it no matter how much I cut it back? The root is about 51/2" in dia.