Are there any products that may be applied to H2 rated timber in a building (floor joists), which may protect the timber to H3? i am looking at lengths of up to 1.5m of floor joists that need to be H3 rated. Is there any way of achieving this, without having to replace the timber?
You will find aerosols and brush-on products on the net described as H3 treatments, but they are 'supplementary products' intended for treating cut ends and notches in timber that has been through a preservative treatment plant. They are not marketed as an alternative to H3 pressure treatment. H3 treatment penetrates into the timber and provides protection against termites and wood rot. H2 treatment protects timber only against termite attack. Since your floor joists will be shielded from the weather they may not need H3 treatment, assuming there is adequate sub-floor ventilation to maintain a dry environment. Note that H3 treatment is one way of dealing with sites that are excessively damp or subject to frequent flooding, according to the ABCB Housing Provisions, but is not required for above-ground floor framing in other circumstances.
Can you do a diagram with metal fascia as your diagram now is with timber fascia?
Metal or timber fascias can be used in BAL-FZ areas, over fire-resistant linings. This is shown in our Regulatory Information Report RIR 23626A which can be downloaded from our website free of charge via this link https://www.woodsolutions.com.au/resources/standards-codes/fire-test-reports. Refer section 9 of the report for details of the fire resistant fascia linings, and section 10 for installation of the fascia itself.
I noticed in the BAL FZ you have 15mm ply. Can you use any type of 15 mm ply on top of the trusses and rafters?
The metal sheet roof system for BAL-FZ (Flame Zone), assessed by Warringtonfire, was based on 15mm pine plywood or 15mm OSB roof lining.
