If the pole is hardwood the creosote has most likely only penetrated the outer band of sapwood. Theoretically the sapwood could be sawn off, leaving a square of clean timber that could be re-sawn into smaller sizes if desired. However, in practice there are a few unknowns. The main issue is that although penetration will be largely confined to the sapwood, creosote will have penetrated more deeply via any cracks that were pre-existing in the wood at the time of treatment. Also if the pole is softwood, penetration is likely to be deeper.

Your timber trusses can be visually stress graded in situ as long as access is available and all surfaces are visible. Australian Standard 2858 contains grading rules for softwoods, and Australian Standard 2082 for hardwoods. We don't have a contact in the Newcastle area but we suggest you contact Timber Training at Creswick.

Since timber has strongly directional characteristics there are six Poisson's ratios.

Reverse cycle air conditioning does have a drying effect on timber - in fact drying timber in dehumidification kilns relies on this principle. Your additional details via email indicate that the house in question is at Wodonga in northern Victoria and will be well insulated, with air conditioning only operated intermittently. CSIRO advises that in Melbourne in an air conditioned environment timber moisture content will range from 7-10% with an average of 9%, although in an uncontrolled indoor environment it will range from 10-13%.

We understand you have already accessed the CSR Red Book for details of System 2340. If the Red Book doesn't provide the information you need, or you require a fire test report, CSR's DesignLINK Technical Support Team may be able to help, phone 1800 621 117.