Laying Out Roofing
51. Measure the distance from the ridge to the eave along the rafter
and add 2 inches for metal overhang. This is the length to use
when figuring the required length of the roofing sheets (see Fig.
13).
Figure 13. Laying out roofing
52. Choose roofing sheet lengths that overlap at least 8 inches at
each joint. Consult your dealer to determine what lengths are
available.
53. You can sometimes get the right overlap by using a different
width ridge roll, which allows the top sheet to start farther down
from the ridge. Extend the lower sheet 2 inches below the first
nailing girt.
54. Measure the distance along the ridge from the outer edge of
the end rafters and add 1 foot (6 inches on each end) for finishing
(see Fig. 14).
55. Most sheets cover a 2-foot width. Divide the total distance (from
step 54) by 2 feet to find the number of rows you need. Roofing
is sold by the square (10 feet by 10 feet), or by 100 square feet.
A square will not cover 100 square feet, because it does not allow
for overlaps. If you use sheets other than 2 feet wide, consult
your roofing material supplier about coverages.