(A) All sidewalks hereafter constructed upon the streets or avenues of the city shall be constructed of concrete and finished with Portland or other standard cement, and all sidewalks hereafter constructed shall be under specifications to be furnished by the City Engineer. The specifications shall require the ingredients and proportions thereof as will secure a hard and durable sidewalk, constructed according to the most approved methods.
(B) All walks shall be laid flat.
(`90 Code, § 19-11)