The limiting factor in the design of floors is deflection under concentrated loads at panel edges.The Span Ratings in Table 10 apply to APA RATED SHEATHING grades only, and are the minimum recommended for the spans indicated. The spans assume panels continuous over two or more spans with the long dimension or strength axis across supports.*

Recommended live loads are given in Table 9. Spans are limited to the values shown because of the possible effect of concentrated loads.

Nailing recommendations are given in Table 10. Other code-approved fasteners may be used. APA  panel subflooring may also be glued for added stiffness and to reduce squeaks using nailing recommendations in Table 8.

Long edges should be tongue-and-groove or supported with blocking unless:

1. A separate underlayment layer is installed with its joints offset from those in the subfloor. The minimum thickness of underlayment should be 1/4 inch for subfloors on spans up to 24 inches and 11/32 inch or thicker panels on spans longer than 24 inches.

2. A minimum of 1-1/2 inches of lightweight concrete is applied over the panels.

3. 3/4-inch wood strip flooring is installed over the subfloor perpendicular to the unsupported edge.

If floor has become wet during construction, it should be allowed to dry before application of finish floor, including underlayment, hardwood flooring, ceramic tile, etc. After it is dry, the floor should be checked from flatness, especially at joints.

Note:

Provide adequate ventilation and use ground cover vapor
retarder in crawl space. Subfloor must be dry before applying
subsequent layers.

Note:

For buildings with wood or steel framed walls, provide 3/4"
expansion joints with separate floor framing members and
discontinuous wall plates over the joints, at intervals that limit
continuous floor areas to 80 feet maximum in length or width,
to allow for accumulated expansion during construction in wet
weather conditions.

(a) For subfloor recommendations under ceramic tile, refer to Table 12. For subfloor recommendations under gypsum concrete, contact manufacturer of floor trapping.

(b) APA RATED STURD-I-FLOOR may be substituted when the Span Rating is equal to or greater that tabulated maximum span.

(c) Span may be 24 inches if 3/4-inch wood strip flooring is installed at right angles to joists.

(d) 6d common nail permitted if panel is 1/2 inch or thinner.

(e) Span may be 24 inches if a minimum 1-1/2 inches of lightweight concrete is applied over panels.

(f) Other code-approved fasteners may be used.

(g) Check with supplier for availability.

(h) Fasteners shall be located a minimum 3/8 inch from panel edges.