Structural Plywood Specification – Residential Flooring

Manufacturing Standards

All PAA T&G plywood panels are manufactured to AS/NZS2269-1994 "Plywood - Structural", and must be stamped with the PAA Product Certification stamp. The PAA has received accreditation from the Joint Accreditation System of Australia and New Zealand (JAS-ANZ) as a product certification body for plywood and laminated veneer lumber. Therefore, the PAA brand certifies that the plywood has been manufactured to AS/NZS2269.

Durability

All structural plywood manufactured to AS/NZS2269 has the permanent Type A 'marine' bond. This bond is achieved using a phenolic adhesive that is distinctively dark in colour. The proven durability of this bond makes structural plywood flooring well suited for floors in wet area rooms. However, standard structural plywood flooring is not recommended for permanently exposed verandahs and decks.

Stress Grades

Standard T&G structural plywood flooring for residential applications is readily available in two stress grades; F11 and F14. Plywood flooring thickness, stress grade and allowable span details for residential floors are provided in Table 1. Plywood flooring panels with higher stress grades; F17, F22, F27 and F34, are available for commercial and industrial flooring applications.

Face and Back Grades

Standard T&G plywood panels are specified as CD grade. The standard face grade is 'C' which is a non-appearance grade with a solid surface. The face is suitable for direct covering with a wide range of floor coverings such as vinyl or cork. The standard grade for the back of the panel is 'D'. The D grade surface can contain open defects such as knots, holes and splits.

T&G structural plywood is also available with a C grade face and a decorative, usually grooved back which gives a planked timber effect. This product is suitable for applications where the panels are to be used as a combined floor and ceiling or as a structural non-trafficable roof.

Dimensions and Tolerances

T&G structural plywood is available in sizes to suit 400, 450, 480 and 600mm joist spacings. Shown below are the common sizes, however, regional factors may influence the availability of some of these:

2250mm x 1200mm

2400mm x 1200mm

2700mm x 1200mm

The above dimensions are the actual panel cover. The first dimension is the length of the panel along the face grain, the second the width across the grain. The tolerance on length and width is 1.5mm.

The standard thicknesses of T&G structural plywood vary between manufacturers. The tolerance on stated thickness is 3%. It is best to check which thicknesses and panel sizes are available through the PAA plywood merchants.

Density

As timber is a natural material and a range of species are used to manufacture plywood, the density can vary between panels. As a guide F11 stress grade plywood averages 550kg/m³ while F27 stress grade plywood averages 850kg/m³.

Tongued and Grooved Edges

T&G structural plywood is tongued and grooved along the length of the panel to eliminate the need for nogging under panel edges. Panel ends are not tongued and grooved and must be supported. The tongued and grooved edge has a design load capacity of 2.7kN point live load at mid span. The T&G edge is suitable therefore for all residential flooring applications.

Branding

All PAA quality controlled T&G structural plywood is branded as follows:-

Manufacturers Name or Brand, The word 'Structural', face grade, back grade and bond, (e.g. CD-A Bond), Stress Grade, (e.g. F11 or F14), the Australian /New Zealand Standard AS/NZS2269 and the PAA/JAS-ANZ product certification brand stamp.

Reference: Plywood Association of Australia brochure: "T&G Structural Plywood for Residential Flooring"

TABLE 1: Plywood flooring thickness, span and stress grade for residential floors.

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