Permanent monuments shall be accurately set and established at the intersections of all outside boundary lines of the subdivision; at the intersections of those boundary lines with all street lines; at the beginning and end of all curves; at points on curves where the radius or direction changes; and at such other points as are necessary to establish definitely all lines of the plat, including all lot corners. Concrete monuments at least thirty-six inches long and at least six inches in diameter shall be used at the intersections of subdivision boundary lines; iron pin or iron pipe monuments at least three-quarters of an inch in diameter and at least thirty inches long shall be used at all other points. All permanent monuments shall be set after construction is complete.