1. All superstructures shall consist of masonry, concrete, glazed sewer pipe, iron or steel. No lumber or other perishable material shall be used, except when absolutely necessary.
2. For the better guidance of road construction and the expenditure of money for the same, the board of county highway commissioners shall observe this order of construction as far as it is possible so to do:
First. The laying out of a road on the most practical grades and alignment.
Second. The grading and draining of such road.
Third. The construction of permanent superstructures.
Fourth. The graveling or macadamizing of all such roads.
Fifth. The maintaining of the same.