What thickness of plywood is used for wall bracing in Australia?
4 mm and 7 mm F22 hardwood plywood cover the majority of AU residential bracing schedules. 4 mm is the volume default for single-storey and lighter loaded walls at 600 mm stud centres; 7 mm appears where the racking demand is higher, stud spacings push to 450 mm centres, or the build is two-storey. 9 mm and 12 mm are used on heavier walls and cyclonic-zone applications.
What is F22 plywood?
F22 is an Australian / New Zealand stress grade under AS/NZS 2269. The number is the characteristic bending strength in MPa, so an F22 panel is rated to 22 MPa nominal. F22 hardwood plywood is the workhorse AU bracing grade because it gives substantial racking capacity at thin sections (4 mm or 7 mm), tolerates site humidity during construction, and is supplied through every major timber merchant.
Does plywood bracing need to be EWPAA stamped?
For audit and certification purposes, yes. The EWPAA stamp on the panel face or edge proves the F-grade, the bond type (Type A phenolic or Type B melamine), the AS/NZS 2269 reference, and the manufacturer code. Where a panel is sold as 'structural' without the EWPAA stamp, the certifier may refuse to credit it against the bracing schedule on the engineer's drawings.
What is the standard nailing pattern for plywood bracing?
AS 1684 standard fixing is 150 mm centres along the panel perimeter and 300 mm centres along intermediate studs and noggings. Edge distance is a minimum 10 mm from the panel edge to the centre of the fixing. Fastener is typically a Type 17 wood screw or a 2.8 x 30 mm flat-head clout. Sloppy perimeter spacing is the most common reason a bracing audit fails — the perimeter pattern is what locks the diaphragm to the studs.
Can plywood bracing be used in cyclonic wind zones?
Yes, but the panel grade and the hold-down detail both step up. C1 through C4 zones (Northern QLD, NT cyclonic coast) require F27 or heavier panels, often 7 mm or 9 mm thick, with continuous tie-down from rafter to footing. The bracing capacity per metre is set by a separate engineer's bracing schedule, not by the generic AS 1684.4 simplified tables, because the cyclonic wind classifications fall outside the non-cyclonic simplified scope.
