Georgia-Pacific APA Engineered Wood Construction Guide - Walls - Manual (Page 12)

Wall Construction
ENGINEERED WOOD CONSTRUCTION GUIDE ■ FORM NO. B360P ■ © 2011 APA – THE ENGINEERED WOOD ASSOCIATION ■ WWW.APAWOOD.ORG 53
APA Sheathing Under Stucco
Greater stiffness is recommended for wall sheathing when stucco is to be applied. To increase stiffness, apply the long
panel dimension or strength axis across studs. Blocking or a plywood cleat is recommended at horizontal joints. Blocking
is required for shear wall and wall bracing applications. For panel recom men dations applied horizontally or vertically,
see Table 25.
Siding Joint Details
The siding joint details in Figure 17 are based on the use
of APA trademarked siding. Nailing of wood structural
panel siding along both edges of shiplap joints (“double
nailing”), as shown, is required for shear walls or those
wall segments that must meet bracing requirements.
Double nailing is recommended for all other applica-
tions as well to provide maximum wall strength and
moisture protection.
Where caulks or joint sealants are indicated, consider
the various types available such as urethane, plasti-
cized acrylic latex, butyl and polysulfide. Check with
the manufacturer of the caulk or sealant to determine
suitability for the intended application and compati-
bility with coatings and other building materials such
as vinyl and aluminum.
In some cases, a foam backer rod or other type filler
material may be used behind the sealants as recom-
mended by the manu facturer. For best results in other
cases, apply caulking to framing at panel edges before
installing the siding panel; or apply a bead of caulk
along the panel edge before installing the next panel.
A 1/8-inch space is recommended at all edge and end
joints unless otherwise indicated by panel manufac-
turer. If caulk is to be used, also check with caulk
manu facturer for recommended edge spacing. Nails
through battens or other wood trim must penetrate
at least 1 inch into studs. Nail panel siding 6 inches
o.c. along edges and 12 inches o.c. at intermediate
supports. To prevent staining of siding, use hot-dip
galvanized, aluminum, or other nonstaining nails as
described on
page 48 .
Siding is often fully exposed to weather and thus has
increased susceptibility to elevated moisture conditions.
Although siding will periodically experience mois ture
contents above the threshold value needed to support
decay, wood-based siding products have a good history
of performance because they dry below this threshold value before decay can initiate. If trim is installed around siding, be
sure that it doesn’t trap moisture or reduce the drying ability of the wood. Trim that is applied incorrectly can lead to long-
term moisture accu mu lation that causes decay.
Apply flashing or other means of protection over end grain of siding to minimize water absorption.
APA RATED SHEATHING
Stucco
FIGURE 16
STUCCO OVER APA PANEL SHEATHING
Metal bead
Self-furring
metal lath
Two layers of
building paper
required*
Note:
*International Building Code
requires two layers of
grade D paper for stucco
over wood-based sheathing.
Check local building code and applicator
for specific requirements.
TABLE 25
RECOMMENDED THICKNESS AND SPAN RATING FOR APA
PANEL WALL SHEATHING FOR STUCCO EXTERIOR FINISH
Stud
Spacing
(in.)
Panel
Orientation (a)
APA Rated Sheathing (b)
Minimum
Performance
Category
Minimum
Span Rating
16
Horizontal (c) 3/8 24/0
Vertical
7/16 (d) 24/16
15/32 (e) , 1/2 (e) 32/16
24
Horizontal (c) 7/16 24/16
Vertical 19/32 (e) , 5/8 (e) 40/20
(a) Strength axis (typically the
long panel dimension)
perpendicular to studs for
horizontal application; or
parallel to studs for vertical
application.
(b) Recommendations apply
to all-veneer plywood or
oriented strand board (OSB)
except as noted.
(c) Blocking recommended between
studs along horizontal panel joints.
(d) Structural I Rated Sheathing (OSB).
(e) OSB or 5-ply/5-layer plywood.