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Choosing the correct plywood

Choosing the correct plywood

Choosing the correct plywood

Plywood, is a timber panel that is made up of cross laminating veneers or (plies) that are then bonded together. The alternating stacking of the veneers help with the stability of the product as it reduces the likelihood of the wood splitting when it is nailed at the edges. The number of plies per board is always an odd number, with three being the lowest number.

Ask the right questions

The typical plywood groups are: Marine, Exterior, Interior, Structural, Non Structural and Formply. To help you decide the right one for the job, there are four questions to ask before selecting the correct plywood for the application:

  • What’s the application?
  • Is there a structural requirement?
  • Is it being used outside or need to be treated against hazards?
  • Is the type of face going to be appearance or non-appearance?

By assessing the answers to these questions, your choices for plywood products will be narrowed down to a few select options, which will ensure the safe and long-lasting application of the product for any type of build. In other words fit for the job at hand. 

F Grade

The strength of structural plywood is measured via the F grade of the product. The higher the number, the more stress it can resist. To achieve the F rating, the plywood undergoes a series of tests and the result is the branded plywood. For instance, the CD ply stocked at NHS is F8 rated structurally.

Is there a Hazard Class?

The Hazard class outlines the treatment of the plywood. The H class of the product will help determine if it can be used in internal or external applications. Special considerations will have to be made for external installations as it will need to be protected against pests and the elements.

Face Grades

Choosing the ideal plywood means you need to get the grading right, to ensure that the look and feel is fit for purpose.

Veneer Quality A

This is a high quality appearance grade veneer substrate suitable for clear finishing

Veneer Quality S

Defines an appearance grade veneer that permits natural characteristics such as knots as a decorative feature subject to agreement

Veneer Quality B

This appearance grade is suitable for high grade quality paint finishing

Veneer Quality C

Defined as a non-appearance grade with a solid surface. All open defects such as holes or splits are filled.

Veneer Quality D

This is a non-appearance grade with permitted open imperfections. Knots and knot holes up to 75mm wide are permitted

 

There are plywood sheets available that have different veneers on each side, a common example is CD plywood. This product has a Veneer Quality C on one side and Veneer Quality D on the other. Specifying a ply with an appearance face and a non-appearance face on the reverse, allows the product to be used in different parts of the build as required. 

Glue Bonds

There are four types of glue bonds used for plywood manufacture, in decreasing order of durability:

  • Type A: Will not weaken under wet conditions, heat, or cold
  • Type B*: Suitable for exterior applications including concrete formwork
  • Types C and D*: Not recommended for structural applications

*B, C, and D glues are white/clear in colour, which eliminates glue bleed through

Exterior ‘waterproof glued’ plywood

There are different varieties manufactured to the Australian Standards:

Marine: manufactured to AS/NZS2272, is the “Rolls Royce” of plywoods with A grade veneer faces both sides

Exterior plywood: manufactured to AS/NZS2271, wither Type A or Type B Bond. Exterior plywood is a non-structural plywood where a high-quality aesthetic finish is required. A Grade for clear finishing and B Grade for painting

Select from our range of plywood products

We supply a wide variety of plywood products available in-store or by special order. Below are some of the available options, you can visit our website for more information or visit our branches.

Product Plybrace F22 Plybrace F8 CD Ply Formply F17 Plyfloor *
Thickness 4mm 7mm 7mm, 9mm, 12mm, 15mm, 17mm & 19mm 17mm 17mm
Sheet sizes 2440x1200, 2745x1200 2440x1200, 2745x1200 2400x1200 2400x1200 2400x1200
Face grade DD DD CD N/A CD
Glue grade A A A A A
F rating F22 F8 F8 F17 F11
Hazard level untreated untreated untreated untreated H3
Applications walls and roofs/ pallets walls and roofs/ pallets construction/ displays/ hoardings concrete formwork subfloors/ stages

 * Available at Cardiff only