studs, and the total effective penetration into the wood
should be at least 1 1/2 inches. For example, 3/8-inch
plywood siding over 3/4-inch wood sheathing would
require a 7d nail (which is 2 1/4 inches long). This would
result in a 1 1/8-inch penetration into the stud, but a total
effective penetration of 1 7/8 inches into the wood
sheathing.
The joints of all types of sheet material should be
caulked with mastic unless the joints are of the
interlapping or matched type of battens. It is a good
practice to place a strip of 15-pound asphalt felt under
joints.
CORNER COVERINGS
The outside corners of a wood-framed structure can
be finished in several ways. Siding boards can be
miter-joined at the corners. Shingles can be edge-lapped
alternately. The ends of siding boards can be butted at
the corners and then covered with a metal cap.
Corner Boards
A type of corner finish that can be used with almost
any kind of outside-wall covering is called a corner
board. This corner board can be applied to the corner
with the siding or shingles end-or-edge-butted against
the board.
A corner board usually consists of two pieces of
stock: one piece 3 inches wide and the other 4 inches
wide if an edge-butt joint between the corner boards is
used. The boards are cut to a length that will extend from
the top of the water table to the bottom of the frieze.
They are edge-butted and nailed together before they are
nailed to the corner. This procedure ensures a good tight
joint (fig. 4-5). A strip of building paper should be tacked
over the corner before the corner board is nailed in
position (always allow an overlap of paper to cover the
subsequent crack formed where the ends of the siding
butts against the corner board).
Interior Corners
Interior corners (fig. 4-6, view A) are butted against
a square corner board of nominal 1 1/4- or 1 3/8-inch
size, depending on the thickness of the siding.
Mitered Corners
Mitering the corners (fig. 4-6, view B) of bevel and
similar sidings is often not satisfactory, unless it is
carefully done to prevent openings. A good joint must
Figure 4-5.-Corner board.
fit tightly the full depth of the miter. You should also
treat the ends with a water-repellent preservative before
nailing.
Metal Corners
Metal corners (fig. 4-6, view C) are perhaps more
commonly used than the mitered corner and give a
mitered effect. They are easily placed over each corner
as the siding is installed. The metal corners should fit
tightly and should be nailed on each side to the sheathing
or corner stud beneath. When made of galvanized iron,
they should be cleaned with a mild acid wash and primed
with a metal primer before the structure is painted to
prevent early peeling of the paint. Weathering of the
metal will also prepare it for the prime paint coat.
corner boards (fig. 4-5) of various types and sizes
may be used for horizontal sidings ofaall types. They also
provide a satisfactory termination for plywood and
similar sheet materials. Vertical applications of matched
paneling or of boards and battens are terminated by
lapping one side and nailing into the edge of this
member, as well as to the nailing members beneath.
corner boards are usually 1 1/8 or 1 3/8 inches wide. To
give a distinctive appearance, they should be quite
narrow. Plain outside casing, commonly used for
window and doorframes, can be adapted for corner
boards.
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