China Radiata Pine Plywood Grades Rules and Standards,Now ,the top volume plywood types exporting to the USA is the radiata pine plywood ,so many factories and plywood buyers and importers have different kinds of radiata pine plywood grading rules ,not just the natural characteristics but also the manufacturing defects ,no any uniform softwood pine plywood grading rules .Let’s explain what is softwood plywood and the softwood species included ,then will understand better the softwood plywood .
Softwood Plywood is plywood which has a face and back veneer of softwood as opposed to a hardwood such as Birch, Maple, Oak, etc. Softwood plywood panels are comprised of a core made from either softwood then faced and backed with a veneer of soft wood and therefore are used for structural applications.
TYPES OF SOFTWOOD PLYWOOD (CONIFER OR GYMNOSPERMS)
Cedar, Douglas fir, Pine, Spruce, Redwood, and more. Note, Softwood plywood which has a face and back veneer of top grades of softwood such as Fir (vertical grain), Clear Pine, Cedar or Knotty Pine may also be considered “Hardwood plywood’s” as they are used for decorative purposes.
SOFTWOOD PLYWOOD USES
Softwood Plywood is used mainly in the construction industry for structural purposes. There are many grades, sizes and thicknesses of softwood plywood depending how they are to be used however in the highest of grades they are sometimes used for decorative purposes such as furniture and cabinet making. Most softwood plywood are made with moisture resistant glue (such as phenol resin adhesive#1) and are Exterior Grade panels.
Softwood plywood can be handled with ordinary woodworking tools and basic skills. When hand sawing or cutting on a table saw, support the panels firmly with the best face up. Cut with the best side down when using a portable power saw. Do not force-feed the panel into the tool or the tool into the panel too quickly because this will increase the roughness of the cut and may induce splintering-out on the exit side. Proper backup of the material also can reduce splintering.
|In the United States, standards for most softwood plywood are established by the American Plywood Association in cooperation with the National Institute of Standards and Technology. A Voluntary Product Standard for plywood became effective November 1, 1966, and was revised in 1974 and again in 1983. The mark “PS 1-83” indicates that the panel conforms to the Product Standard published in 1983, which was still in force in 1992. Panels are stamped with a grade mark, unless such a stamp would deface a high quality surface that might be given a natural finish. Such grades are marked on the edges.
Lumber yards usually carry 4 foot by 8 foot and 4 foot by 10 foot panels, but will cut half and quarter sheets. Other sizes are manufactured, almost always in increments of 12 inches, for example, in widths of 36″, 48″ and 60″, and in 9 foot lengths.
The exception to the whole feet rule are panels marked “sized for spacing,” which are slightly shorter than normal panels (e.g., 48 inches by 95½ inches instead of 48 inches by 96 inches) in order to leave space between panels in, for example, sheathing a roof with rafters on 24″ centers. The space is necessary to allow for the panels’ expansion.
Thicknesses of sanded panels range from ¼ inch to 1¼ inch or more, in steps of 1/8 inch. The thickness tolerance is ± 1?64 inch for panels ¾ inch or less and ± 3% of specified thickness for thicker panels.
Nominal thicknesses of unsanded panels range from 5?16 inch to 1¼ inch or more, ± 1?32 inch for panels with a specified thickness of13?16 inch or less, and ± 5% for thicker panels.
Species group number
A number from 1 to 5, with wood from the species of trees in group 1 being the strongest and stiffest (such as beech, Douglas Fir from certain states) and 5 the least stiff and strong (basswood, poplar).
Exposure durability classifications
Panel grade is either
APA trademarked panels
Certain designations are trademarked by the APA, such as “APA Rated Sheathing,” “APA Rated Sturd-I-Floor,” and “APA Rated Siding.” These panels are marked with span ratings, which indicate the maximum center-to-center distance, in inches, between the joists or studs to which the panel is fastened during construction.
In the case of sheathing, the span rating is two numbers separated by a slash:
In both cases the rating assumes that the long dimension of the plywood crosses at least three supports.