Side forms shall be lumber with a nominal width of not less than two inches by four inches, or of steel of equal rigidity, for walks and aprons. Forms for curbs or combined curbs and gutters shall be approved by the Engineer. They shall be held securely in place by stakes or braces, with the top edges true to line and grade. The forms for street sidewalks shall be so set that the slab will have a fall of one-inch vertical to four feet horizontal, from the edge nearest the property line toward the edge farthest from the property line. Forms for the sidewalk aprons shall be set so that the slab will have a uniform fall between the sidewalk proper to the curb grade. (Ord. 352. Passed 10-22-62.)