Increasing yard depth when abutting a residential lot. Where a lot in a B-1 District abuts a lot in a residential district, there shall be provided along such abutting side or rear on said business district lot a yard at least 25 feet in width. In said yard a strip 12 feet wide immediately adjacent to said residential lot shall not be used for storage of any material or goods, parking or roadway. The owner or occupant of the business property shall provide a solid wall, fence or hedge at least six feet but not more than eight feet in height. Such wall, fence or hedge shall begin at a point no more than 30 feet nor less than 20 feet from the front property line and extend along the full dimension of the abutting lots. Such wall, fence or hedge shall be properly maintained by the business property owner or occupant.