| Structural I PLYFORM is stronger and stiffer than
PLYFORM Class I, particularly in the cross-panel direction, and is sometimes used for high
pressures where long dimension is parallel to supports. Additional plywood grades designed
for concrete forming include special overlays and proprietary panels. For complete design information, write for APA's Design/Construction
Guide: Concrete Forming, Form V345.
Structural Insulated Panels
The structural insulated panel, or sandwich panel, offers the
stiffness and load handling capability of a stressed-skin panel, plus light weight, high
insulation values for relatively small thickness, and fast panelized construction. Panels
are prefabricated by sandwiching an insulating core material such as polystyrene or
polyurethane foam, or a paper honeycomb, between wood structural panel "skins".
A structural bond is formed between the core and the skins with full structural glues or,
in the case of some foam materials, by direct adhesion of foam to the skins.
With APA panel siding for the outside skin, structural insulated
panel make attractive, energy-conserving walls on both residential and commercial
buildings. A typical structural insulated floor panel might have 19/32-inch top skin and
3/8-inch bottom skin. Check local building requirements relating to thermal barrier
protection of plastic foam. For additional information, write for Design and
Fabrication of Plywood Sandwich Panels, Form U814.
APA Panels Over Metal Framing
Modern fastening methods are rapidly expanding the use of APA panels
over metal framing. Self-drilling, self-trapping fastener commonly are used to attach
panels up to 1-1/8 inch thick to steel flanges. Panels also can be fastened to lighter
members, such as formed steel joist,s with special hardened screw-shank nails.
Construction adhesives are recommended with hardened screw-shank nails. Consult metal
framing manufacturers for recommended adhesives. Since threads usually extend only part
way up the shank of self-drilling, self-tapping screws and screw-shank nails, it is
important to specify a length sufficient to engage the metal framing.
Typical panel-to-metal framing systems are illustrated in Figure 38.
Load-span recommendations are the same as for wood-frame systems. For more information,
write for APA Design/Construction Guide: Wood Structural Panels Over Metal
Framing, Form T625.
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