The grading rules for recycled decorative products and recycled structural timber are separate documents but were part of the same project and have the same Project Number, PN06.1039. However, they can be differentiated by title, namely Visually Stress Graded Recycled Timber for Structural Purposes, and Visually Graded Recycled Decorative Products.

The 100 x 100 pine treated to H4 level will be protected against wood rot and insect attack. The LVL treated to H2S level will be protected against termite species found south of the Tropic of Capricorn, hence the 'S' designation, but not against wood rot. However, termite attack on the 4th floor, with the timber seated on a concrete slab, is somewhat unlikely. Wood rot is highly unlikely since decay-causing fungi, including so-called "dry rot", require a source of moisture, and the existing slab will presumably be dry if it has been in place for a significant period of time.

Span tables for LVL are published by the producers. At WoodSolutions we haven't published tables of our own. However, it's possible that one of the software design programs available from our website could provide an answer. Various programs can be accessed via this link https://www.woodsolutions.com.au/resources/specifications/span-tables-and-software. Failing that, we suggest you contact an LVL producer or a consulting engineer.

We are not aware of the use of Eucalyptus grandis for CLT, but its general properties can be found on our website via this link https://www.woodsolutions.com.au/wood-species/hardwood/gum-rose. It is known in Australia as "rose gum". Cusp Building Solutions in the State of Tasmania produces CLT from another plantation eucalypt, Eucalyptus nitens, known as "shining gum" so it seems likely that E. grandis would also be suitable with appropriate testing.

The time it takes for wood rot to become established is measured in years rather than months, and it is unlikely that the structural properties of your timber have been affected by exposure to rain in the short term. However, the moisture content of the timber will have to be reduced to 15% or less before internal linings can be installed, and mould growth may appear on the surface in the interim. We would not recommend applying hydrated lime to the damp timber. Hydrated lime has a pH value of around 12, meaning it is highly alkaline.