The National Construction Code (NCC) aims to 'compartmentalise' fire, ie. contain it within a dwelling occupancy or 'fire compartment'. A fire compartment is defined as any part of a building separated from the remainder by barriers to fire such as walls and/or floors having an appropriate resistance to the spread of fire with any openings adequately protected (NCC 2019 p. 649). It follows that internal non-loadbearing walls are not caught up by the regulations, and timber is permitted without the need for fire resistant linings.

We have a comprehensive report titled R-values for Timber-framed Building  Elements, which can be downloaded from our website via this link https://www.woodsolutions.com.au/system/files/R-Values-for-timber-framed-building-elements_1.pdf. It gives R-values for suspended timber floors, bare, carpeted and tiled, with and without RFL insulation.

Our understanding is that CCA treated timber has been restricted for some years as a material for picnic tables, following an extensive review by the Australian Pesticides & Veterinary Medicines Authority (APVMA). The restrictions on picnic tables (also garden furniture, exterior seating, children’s play equipment, patio and domestic decking, and handrails) were introduced on a 'precautionary' basis.