Roof lines should be arrow straight.
Roof line not straight.
This will be the bottom of your board.
The end of the line is 4 inches from the lower edge of the roof which is standard exposure.
Sometimes an uneven roof is simply a sign of minor errors or aberrations in construction.
Sometimes you can adjust gutters and vents for a more uniform appearance.
After your floor is straight it is time to concentrate on the next floor s ceiling.
Repeat this on both sides of the roof.
At other times the gutters may need to stay where they are so gravity can do its work.
It is probably feasible to straighten up the roof line a bit when the metal roof is installed.
Screw a 2x4 about 12 long with a small nail sticking out on the 1 1 2 side.
Screw it into the wall and repeat this on the opposite wall.
Every 5 inches make a new mark until you get to the rop of the roof.
Crooked gutters can make a roof look crooked even if the roofline itself is straight.
Use the chalk line to snap a straight line vertically every 6 inches.
It might be something basic you can handle yourself but.
Run your string line from the nails and measure up from the string.
This droopiness could be caused by moisture and ventilation problems.
Use your chalk and tape measure to mark about 12 inches up on the roof for the first set of shingles.
Ask an assistant to hold the end of a chalk line on the first shingle at the longest edge of the roof.