Mark 12 inches up on the roof for the first course of shingles then mark every 5 inches all the way up the roof to set your reveal.
How to lay shingles on a roof.
To install asphalt shingles start by installing underlayment and new flashing on the roof.
Continue laying your shingles horizontally up the roof.
Use your chalk and tape measure to mark about 12 inches up on the roof for the first set of shingles.
When installing shingles start by laying a narrow row of shingles at the bottom of the roof along the edge.
Repeat this on both sides of the roof.
Then begin nailing the shingles to the roof working in rows and starting at the edge of the roof.
Use the chalk line to snap a straight line vertically every 6 inches.
Next lay the first full row of shingles so they re directly covering the starter row.
To lay out the design for the shingles begin at the bottom of the roof and place a tape measure inch from the edge of the roof to ensure the shingles overhang the drip edge.
Do this on both sides of the roof.
Known in the trade as vertical racking or staggering this how to lay shingles method enables the roofer to install a single column of shingles all the way to the peak without the wasted back and forth motion necessary to fill several rows of stair steps.