Whether the floor is a single layer or double layer, the subfloor panels must bear a Rated Sturd-I-Floor or Rated Sheathing Span Rating of at least 24 for floor joist spacing up to 20 inches o.c. and 32 for joists spaced 24 inches o.c. The thicker panels provide greater floor stiffness and a more solid, high-quality feeling.

Code Plus construction also calls for the APA Glued Floor System. The combination of strong construction adhesives and nails increases floor stiffness and helps eliminate squeaks, bounce and nail-poping.

One of the following construction options may be used:

• For double wall construction, sheath walls with APA Rated Sheathing. It provides an excellent nail base for exterior siding and ties the frame together for increased strength.
• For single wall construction, apply APA Rated Siding panels with a Span Rating of 24 o.c. direct to studs spaced 16 inches o.c.
• Apply APA Rated Siding panels which are at least 19/32 inch thick with no groves or shallow groves which are no deeper than the face veneer direct to studs spaced 24 inches o.c.

One of the following construction systems is used:

• Apply APA Rated Sheathing with a minimum Span Rating of 32/16 to roof framing spaced 24 inches o.c.
• Apply APA Rated Sheathing with a minimum Span Rating of 24/16 to roof framing spaced 16 inches o.c.

Builders and remodelers must also provide adequate ventilation and fasten roof sheathing with 8d nails or other code-approved fasteners.