Figure 4-10.-Flashing of material changes: A. Stucco above, siding below, B. Vertical siding above, horizontal below.
wood backing strips or sheathing. In a single course, a
3d or 4d zinc-coated shingle nail is commonly used. In
a double course, where nails are exposed, a 5d
zinc-coated nail with a small flat head is used for the top
course, and a 3d or 4d size for the undercourse. Use
building paper over lumber sheathing.
FLASHING
Flashing should be installed at the junction of
material changes, chimneys, and roof-wall
intersections. It should also be used overexposed doors
and windows, roof ridges and valleys, along the edge of
a pitched roof, and any other place where rain and
melted snow may penetrate.
To prevent corrosion or deterioration where unlike
metals come together, use fasteners made of the same
kind of metal as the flashing. For aluminum flashing,
use only aluminum or stainless steel nails, screws,
hangers, and clips. For copper flashing, use copper nails
and fittings. Galvanized sheet metal or terneplate should
be fastened with galvanized or stainless steel fasteners.
(Terneplate is a steel plate coated with an alloy of lead
and a small amount of tin.)
One wall area that requires flashing is at the inter-
section of two types of siding materials. For example, a
stucco-finish gable end and a wood-siding lower wall
should be flashed (fig. 4-10, view A). A wood molding,
such as a drip cap, separates the two materials and is
covered by the flashing, which extends at least 4 inches
above the intersection. When sheathing paper is used, it
should lap the flashing (fig. 4-10, view A).
When a wood-siding pattern change occurs on the
same wall, the intersection should also be flashed. A
vertical board-sided upper wall with horizontal siding
below usually requires some type of flashing (fig. 4-10,
vie w B). A small space above the molding provides a
drip for rain. This will prevent paint peeling, which
could occur if the boards were in tight contact with the
molding. A drip cap (fig. 4-7) is sometimes used as a
terminating molding.
DOOR AND WINDOW FLASHING
The same type of flashing as shown in figure 4-10,
view A, should be used over door and window openings
exposed to driving rain. However, window and door
heads protected by wide overhangs in a single-story
structure with a hip roof do not ordinarily require the
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