Sheet laying procedure

Photo of a house with metal roof sheeting. A diagram overlays the photo showing the direction of the sheet laying in the opposite direction of prevailing weather. Side lap is 1.5 corrugations. The 'under' edge is on the edge facing prevailing weather. The 'over' edge is on the opposite side.
Completed roof with all sheets laid

Diagram showing a plan of a house roof divided into sections corresponding to the sheets of roofing to be laid. The sections are numbered to show the order in which the sheets are to be laid.
Order in which sheets are laid