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Building Design and Construction Handbook - Merritt - Ventech!

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10.44 SECTION TEN<br />

<strong>Building</strong> paper is generally not required over wall sheathing, except under stucco<br />

or under brick veneer where required by the local building code. Recommended<br />

wall sheathing spans with brick veneer <strong>and</strong> masonry are the same as those for<br />

nailable panel sheathing.<br />

10.12.9 Allowable Loads for APA Structural-Use Panels<br />

Because it is sometimes necessary to have engineering design information for structural<br />

panel products for conditions not specifically covered in other literature, APA<br />

publishes separate design-section capacities for the various span ratings for these<br />

products. These values are listed in APA Technical Note N375, ‘‘<strong>Design</strong> Capacities<br />

of APA Performance-Rated Structural-Use Panels.’’ The APA ‘‘Plywood <strong>Design</strong><br />

Specification’’ contains load-span tables that apply to APA trademarked structuraluse<br />

panels qualified <strong>and</strong> manufactured in accordance with PS 2-92 or APA PRP-<br />

108, ‘‘Performance St<strong>and</strong>ards <strong>and</strong> Policies for Structural-Use Panels.’’ These panels<br />

include plywood, composite, <strong>and</strong> mat-formed products, such as oriented str<strong>and</strong><br />

board. Loads are provided for applications where the panel strength axis is applied<br />

across or parallel to supports. For each combination of span L <strong>and</strong> Span Rating,<br />

loads are given for deflections of L/360, L/240 <strong>and</strong> L/180, <strong>and</strong> maximum loads<br />

controlled by bending <strong>and</strong> shear capacity. The values may be adjusted for panel<br />

type, load duration, span conditions, <strong>and</strong> moisture. Table 10.22 is provided to assist<br />

in selecting panel constructions for specific span ratings.<br />

Some structural-panel applications are not controlled by uniform loads. Residential<br />

floors are a good example. They are commonly designed for 40-psf live<br />

load. The allowable uniform floor load on panels with maximum span according<br />

to APA recommendations is greatly in excess of typical design loads. This excess<br />

does not mean that floor spans for structural panels can be increased, but only that<br />

there is considerable reserve strength <strong>and</strong> stiffness for uniform loads. Actually, the<br />

TABLE 10.22 Typical APA Panel Considerations*<br />

Span rating<br />

APA Rated Sheathing<br />

Plywood<br />

3-Ply 4-Ply 5-Ply† COM-PLY OSB<br />

24/0 X X<br />

24/16 X<br />

32/16 X X X X<br />

40/20 X X X X<br />

48/24 X X X<br />

APA Rated Sturd-I-Floor<br />

16 in c to c<br />

20 in c to c X X X X<br />

24 in c to c X X X X<br />

32 in c to c X X X<br />

48 in c to c X X X<br />

* <strong>Construction</strong>s may not be available in every area. Check with suppliers<br />

concerning availability.<br />

† Applies to plywood with five or more layers.

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