Plywood Types Explained: Non-Structural, Structural, Bracing, Marine, Formply & More

"Plywood" sounds like one product, but walk into any supplier and you'll find a dozen versions that look almost identical and behave completely differently. Pick the wrong one and you've either overpaid for performance you'll never use, or — far worse — put a non-structural sheet somewhere it has to carry load. This guide breaks down the main types of plywood used in Australian construction, what each standard actually means, and how to choose with confidence.

How plywood is graded in Australia

Before the types, three things separate one sheet from another:

The bond (glue line). This determines how much moisture the sheet can handle. Type A is a permanent phenolic bond used for marine and full-exposure exterior work. Type B is semi-durable. Type C and Type D are interior bonds — Type C suits humid interiors like bathrooms, Type D suits normal interior conditions.

The veneer quality (face and back). Veneers are graded A, S, B, C and D, from a near-flawless finish (A/S) down to a structural back that may contain knot holes or splits (D). That's why you'll see sheets described as "BC" (B face, C back) or "CD" (C face, D back) — the first letter is the side you see.

The stress grade (structural only). Structural sheets carry an F-rating — F8, F11, F14, F17, F22 and up — describing stiffness and strength. The higher the number, the stronger the panel.

The main types of plywood

Structural plywood (AS/NZS 2269)

The workhorse. Structural plywood is the only wood panel with defined, engineered structural properties, made with a Type A bond and an F-stress grade. Use it anywhere the sheet has to brace, span, carry or stiffen — subfloors, walls, roofs and formwork. Our CD F11 Structural Plywood is the standard general-construction choice.

Interior / non-structural plywood (AS/NZS 2270)

For lining, cabinetry, display and general-purpose work where there's no load and no moisture. It uses interior C/D bonds and should never be used in wet or load-bearing applications. Our BC Non-Structural Plywood has a smooth B face for visible surfaces and a C back for concealed areas.

Bracing plywood

Structural ply made specifically for wall bracing, offering high racking resistance to keep a frame square against wind and lateral loads. Our Plywood Bracing F22 is purpose-built for this.

Marine plywood (AS/NZS 2272 / BS 1088)

The highest grade. Marine ply uses only top-quality veneers, durable timber species and a fully waterproof Type A bond, with minimal internal voids. It's built for boats, wet areas and anywhere prolonged water contact is expected. See our Marine Plywood BS1088.

Formply (AS 6669)

Concrete formwork plywood with a phenolic film face that gives a smooth finish and releases cleanly from set concrete, then survives multiple pours. We stock both Formply F17 for structural formwork and a non-structural film-face option for general work.

Tongue & groove plywood

Structural flooring ply with interlocking edges for a tight, even subfloor with no gapping. See Tongue & Groove Plywood F11.

How to choose, in three questions

1. Does the sheet carry load? If it braces, spans, carries or stiffens anything, you need structural (AS/NZS 2269) with the right F-grade.
2. Will it get wet? Permanent water contact = marine (2272). Dry interior = interior (2270).
3. Does the face show? Choose your veneer grade accordingly — a B or better face for visible work, a C/D back where it won't be seen.

Get those three right and you'll specify the correct sheet every time — and avoid the most expensive plywood mistake, which is paying for the wrong standard.

Browse the full range of Plywood at Tramin, with builder discounts and Sydney-wide delivery.