2.
3.
4.
5.
6.
Figure 3-26.-Installation of wood shingles.
Use two rust-resistant nails in each shingle.
Space them 3/4 inch from the edge and 1 1/2
inches above the butt line of the next course.
Double the first course of shingles. In all
courses, allow 1/8- to 1/4-inch space between
each shingle for expansion when they are wet.
Offset the joints between the shingles at least 1
1/2 inches from the joints in the course below.
In addition, space the joints in succeeding
courses so that they do not directly line up with
joints in the second course below.
Where valleys are present, shingle away from
them. Select and precut wide valley shingles.
Use metal edging along the gable end to aid in
guiding the water away from the sidewalls.
Use care when nailing wood shingles. Drive the
nails just flush with the surface. The wood in
shingles is soft and can be easily crushed and
damaged under the nail heads.
Wood shakes are usually available in several types,
but the split-and-resawed type is the most popular. The
sawed face is used as the back face and is laid flat on the
roof. The butt thickness of each shake ranges between
3/4 inch and 1 1/2 inches. They are usually packed in
bundles of 20 square feet with five bundles to the square.
Wood shakes are applied in much the same way as
wood shingles. Because shakes are much thicker (longer
shakes have the thicker butts), use long galvanized nails.
To create a rustic appearance, lay the butts unevenly.
Because shakes are longer than shingles, they have
greater exposure. Exposure distance is usually 7 1/2
inches for 18-inch shakes, 10 inches for 24-inch shakes,
and 13 inches for 32-inch shakes. Shakes are not smooth
on both faces, and because wind-driven rain or snow
might enter, it is essential to use an underpayment
between each course. A layer of felt should be used
between each course with the bottom edge positioned
above the butt edge of the shakes a distance equal to
double the weather exposure. A 36-inch-wide strip of
the asphalt felt is used at the cave line. Solid sheathing
should be used when wood shakes are used for roofs in
areas where wind-driven snow is common.
ROLL ROOFING.— Roll roofing is made of an
organic or inorganic felt saturated with an asphalt
coating and has a viscous bituminous coating. Finely
ground talc or mica can be applied to both sides of the
saturated felt to produce a smooth roofing. Mineral
granules in a variety of colors are rolled into the upper
surface while the final coating is still soft. These mineral
granules protect the underlying bitumen from the
deteriorating effects of sun rays. The mineral aggregates
are nonflammable and increase the fire resistance and
improve the appearance of the underlying bitumen.
Mineral-surfaced roll roofing comes in weights of 75 to
90 pounds per square. Roll roofing may have one
surface completely covered with granules or have a
2-inch plain-surface salvage along one side to allow for
laps.
Roll roofing can be installed by either exposed or
concealed nailing. Exposed nailing is the cheapest but
doesn’t last as long. This method uses a 2-inch lap at the
side and ends. It is cemented with special cement and
nailed with large-headed nails. In concealed-nailing
installations, the roll roofing is nailed along the top of
the strip and cemented with lap cement on the bottom
edge. Vertical joints in the roofing are cemented into
place after the upper edge is nailed. This method is used
when maximum service life is required.
Double-coverage roll roofing is produced with
slightly more than half its surface covered with granules.
This roofing is also known as 19-inch salvage edge. It
is applied by nailing and cementing with special
adhesives or hot asphalt. Each sheet is lapped 19 inches,
blind-nailed in the lapped salvage portion, and then
cemented to the sheet below. End laps are cemented into
place.
TILES.— Roofing tile was originally a thin, solid
unit made by shaping moist clay in molds and drying it
in the sun or in a kiln. Gradually, the term has come to
include a variety of tile-shaped units made of clay,
Portland cement, and other materials. Tile designs have
come down to us relatively unchanged from the Greeks
and Remans. Roofing tiles are durable, attractive, and
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