All bill or sign boards now erected or existing within the city which do not conform to the provisions of this chapter, shall, within sixty (60) days after the passage of this chapter, be so altered or repaired as to conform to the provisions of this chapter, or shall be removed; and in case of failure of the owner or lessee of such board to so alter, repair or remove the same, the chief of police shall have such board torn down, and the owner or lessee thereof shall be liable to the city for the cost of such removal. All existing boards shall be licensed within thirty (30) days after the passage of this chapter, or shall be torn down or removed as above provided. (R.O. 1959, Ch. 10, Art. 2, Sec. 8)