After the adoption of such zoning regulations or building line regulations by the board of county commissioners, no building or other structure within the area authorized by this act¹ to be zoned shall be erected, constructed, enlarged or altered in such manner as to prolong the life of the buildings, nor shall the use of any land within such area be changed without a permit issued by the county engineer. The county engineer shall have the duty of administering the rules and regulations under this act and shall make such inspections and investigations as may be necessary to the proper enforcement of such rules and regulations.