The material used for construction of fences or walls shall be wrought iron, wood, decorative block, brick, stone veneer, or a stucco finish to match the finish of the building. Additional material such as chain link fence and precision block shall be permitted. On any boundary line which is a common property line with R classified property, a solid wall or view-obscuring fence of solid brick or decorative block, not less than six feet or more than ten feet in height, shall be installed and maintained for screening purposes and controlling trespass, except where the wall of a building is on such common property line, no separate wall need be installed along the portion of the property line occupied by the wall of a building;