customer wants me to trim some savannah holly trees. they about 30ft in height and have grown out of control. stick about 8ft above the roof on a 2-story house! they are only about 2.5ft away from the house. the wife wants to remove them completely because of the how large they are. with a tree this size, wht size root spread am i looking at? reason i ask is because they are worried the roots are growing under the slab of the home! any help? thanks in advance to the Pros!