Figure 7-19.-Open-frame construction.
(fig. 7-19), nails are driven one-half their length into the
wood. Spacing should be 5 to 6 inches OC from the
bottom. Nails should be placed at all corners and
openings throughout the entire structure on the exterior.
The next step is to place wire on the nails. This is
called installing the line wire. Next, a layer of water-
proof paper is applied over the line wire. Laps should be
3 to 4 inches and nailed with roofing nails. Install wire
mesh (stucco netting), which is used as the reinforce-
ment for the stucco.
Furring nails (fig. 7-20) are used to hold the wire
away from the paper to a thickness of three- eighths of
an inch. Stucco or sheathed frame construction is the
same as open frame except no line wire is required. The
open and sheathed frame construction requires three
coats of 3/8-inch scratch coat horizontally scored or
scratched, a 3/8-inch brown coat, and a 1/8-inch finish
Stucco is usually applied in three coats. The first
coat is the scratch coat; the second the brown coat; and
the final coat the finish coat. On masonry where no
reinforcement is used, two coats maybe sufficient. Start
at the top and work down the wall. This prevents mortar
from falling on the completed work. The first, or scratch,
coat should be pushed through the mesh to ensure the
metal reinforcement is completely embedded for
mechanical bond. The second, or brown, coat should be
applied as soon as the scratch coat has setup enough to
carry the weight of both coats (usually 4 or 5 hours). The
brown coat should be moist-cured for about 48 hours
and then allowed to dry for about 5 days. Just before the
application of the finish coat, the brown coat should be
uniformly dampened. The third, or finish, coat is
frequently pigmented to obtain decorative colors.
Although the colors may be job-mixed, a factory-
prepared mix is recommended. The finish coat maybe
applied by hand or machine. Stucco finishes are
available in a variety of textures, patterns, and colors.
Before the various coats of stucco can be applied,
the surfaces have to be prepared. Roughen the surfaces
of masonry units enough to provide good mechanical
key, and clean off paint, oil, dust, soot, or any other
material that may prevent a tight bond. Joints may be
Figure 7-20.-Several types of furring nails.