Figure 3-25.-Nails suitable for installing strip shingles,
recommended nail lengths, and nail placement.
are laying self-sealing strip shingles in windy areas, the
starter strip is often formed by cutting off the tabs of the
shingles being used. These units are then nailed in place,
right side up, and provide adhesive under the tabs of the
first course.
Nails used to apply asphalt roofing must have a
large head (3/8- to 7/16-inch diameter) and a sharp point.
Figure 3-25 shows standard nail designs (view A) and
recommended lengths (view B) for nominal 1-inch
sheathing. Most manufacturers recommend 12-gauge
galvanized steel nails with barbed shanks. Aluminum
nails are also used. The length should be sufficient to
penetrate the full thickness of the sheathing or 3/4 inch
into the wood.
The number of nails and correct placement are both
vital factors in proper application of rooting material.
For three-tab square-butt shingles, use a minimum of
four nails per strip (fig. 3-25, view C). Specifications
may require six nails per shingle (view C). Align each
shingle carefully and start the nailing from the end next
to the one previously laid. Proceed across the shingle.
This will prevent buckling. Drive nails straight so that
the edge of the head will not cut into the shingle. The
nail head should be driven flush, not sunk into the
surface. If, for some reason, the nail fails to hit solid
sheathing, drive another nail in a slightly different
location.
WOOD SHINGLES AND SHAKES.— Wood
shingles are available in three standard lengths: 16, 18,
and 24 inches. The 16-inch length is the most popular.
It has five-butt thicknesses per 2 inches of width when
it is green (designated a 5/2). These shingles are packed
in bundles. Four bundles will cover 100 square feet of
wall or roof with 5-inch exposure. The 18- or
24-inch-long shingles have thicker butts-five in 2 1/4
inches for the 18-inch shingles and four in 2 inches for
24-inch shingles. The recommended exposures for the
standard wood-shingle size are shown in table 3-6.
Figure 3-26 shows the proper method of applying a
wood-shingle roof. Underpayment or roofing felt is not
required for wood shingles except for protection in ice
jam areas. Although spaced or solid sheathing is
optional, spaced roof sheathing under wood shingles is
most common. Observe the following steps when
applying wood shingles:
1. Extend the shingles 1 1/2 inches beyond the cave
line and 3/4 inch beyond the rake (gable) edge.
Table 3-6.-Recommended Exposure for Wood Shingles
3-20
