Permitted uses, existing structures. A wireless communications facility may be permitted to locate on any existing radio or television transmission tower, guyed tower, lattice tower, monopole, fire tower, water tower, clock tower, bell tower, cross tower, flagpole, road sign, steeple, chimney, silo or other innovative use of appropriate existing structures (as determined by the Planning Board) provided that there is no increase in the height of the existing structure as a result of the installation of the facility. Such installations shall not require a special use permit but will require site plan approval by the Planning Board in accordance with Article VII of this chapter.