Q2
Where or who makes or supplies moulded plywood?

Q4
How do I fix plywood bracing to a steel frame?

Q10
Where can I get Material Group Number 1 or 2 panels for walls and cielings?

Q2.
Where or who makes or supplies moulded plywood?

A. The EWPAA is aware of only two companies that does this:

Euro Laminates, 11 Craig Street, Kyogle NSW 2474
ph: +61 2 6632 1311 contact Jack Dorsman, jack.eurolam@arach.net.au

Plymakers Pty Ltd, 1 Lennox Place, Wetherhill Park NSW 2164
ph: +61 2 9604 5999 contact Jim Johnston, plymake@bigpond.net.au

Q3.
What are the requirements for mezzanine floors?

A. Basically mezzanine flooring can be treated exactly the same as commercial and industrial flooring. This guide is found in the "Technical and Engineering" section of the EWPAA Library. Note that if the mezzanine floor is to be used for storage, it is important to realise that uniformly distributed loads are much easier to achieve the requirements for strength than point loads. Also any reduction in support spans increases the capacity of any structural plywood product. So for your best results on a storage application use pallets (to give a uniformly distributed load) and reduce spans to a minimum.

Q4.
How do I fix plywood bracing to a steel frame ?

A. Many issues dealing with plywood bracing installation are dealt with in the "Structural Plywood Wall Bracing Manual" which can be found in the "Technical and Engineering" section of the EWPAA Library. This manual contains a section on fixings.

For steel frames, it is recommended that this manual be followed, using screws as the fixing method. While the manual does not specifically deal with attaching plywood to steel frames, it does indicate that if screws are used, circular washers of equivalent thickness and nett bearing area should be used. This is due to the fact that screws generally have a larger diameter shaft, with a smaller bearing area, which could lead to the possibility of the screw 'pulling through'.

If screws with a larger nett bearing area (ie. the head diameter is sufficiently larger than the shaft diameter) are available, these can be used without washers.

Q5.
How much does plywood grow and expand with moisture content ?

A. Refer to the following table

Values in yellow in the above table are % dimension per percent change in moisture content.

Worked Example
Determine the hygroscopic expansion in mm across the grain of a 1200mm wide, 17mm thick structural plywood panel, when installed at 10% moisture content and used in a fully exposed application in which the plywood could become fully saturated with water. Assume fibre saturation is 28%.

1. As the range is 10% - 28% the correct selection from Table 4.1 is from the ‘average’ column, and is 0.014% per % change of moisture content.
2. Total change in moisture content = 28% - 10%  = 18%

Q6.
How can I fill out the Form 16 Inspection Certificate for termite resistance in Queensland when I am using H2 treated plywood for primary building elements?

A. The Form 16 Inspection certificate is a document that certifies that a particular building element satisfies a particular BCA building requirement. In the case of termite resistance in Queensland, the BCA performance requirement P2.1.1 states :

Section 3.3 and Appendix D of the standard "Termite Management - New Building Work - AS 3660.1" states that timber treated in accordance with AS 1604 to an H2 level is deemed to be termite resistant in an interior, above ground application.

Accordingly, plywood treated in accordance with AS 1604.3 to an H2 level satisfies the BCA performance requirement P2.1.1 for primary building elements used inside above ground.

It is not good practice to manufacture cupboard doors from simple unrestrained plywood sheets.  Plywood should always be used fixed to a rigid frame and should not be used unrestrained.  Plywood sheets left unrestrained will bow and twist with changes in moisture content bought about by such influences as air conditioning, humidity, wet or dry weather or seasonal climatic changes. 

Cupboard doors can be manufactured using thin plywood, usually 4mm or less,  which has been fixed to a timber door frame.  The rigidity of the frame will prevent the plywood bowing and twisting.

Oil based stains are not recommended on plywood where the finished job will be subject to close scrutiny.  Oil based stains tend to penetrate the face veneer of the plywood and strongly highlight the natural figure in the timber, darkening it considerably.  In many applications this may not be desirable.  Oil based stains also tend to swell the grain of the surface veneer, again potentially disfiguring the plywood.

Q9.
Who makes or supplies perforated plywood or MDF ?

A. Austral Plywoods supplies perforated panels - for an example of what is available, click here.

Q10.
Where can I get Material Group Number 1 or 2 panels for walls and cielings?

A. Austral Plywoods supplies panels with a Material Group Number 1 or 2 (BCA Certified) - for an example of what is available, click here.