We'd like to use timber cladding for a type C single-storey building containing class 5 and 9a portions separated by a fire wall. We noticed that the BCA vol 1 F3D5 excludes timber cladding for classes 2 to 9. Are you aware of any timber cladding that can achieve compliance, either by test report, performance solution or some other pathway?
There is no problem complying with BCA fire requirements since single-storey Type C buildings do not need any specific FRL if 3.0m or more from a fire source feature (Table S5C24a). Clause F3D5 in Volume 1 is aimed at waterproofing and, as you say, does not include timber cladding as a Deemed to Satisfy solution. Currently, a Performance Solution would be required. In our opinion, reference to ABCB Housing Provisions, Part 7.5 Timber and composite wall cladding would provide support for a Performance Solution. The wind is the same, the rain is the same, weatherproofing the same, condensation the same in the same location/climate zone. Logically the same requirements should apply to buildings referenced in BCA Volume 1.
We are building a new house colonial style with surrounding Verandah. The timber deck boards will run parallel with the external wall with a spacer board cut in a 45 degrees angle at the change of direction, there will be butt joints at the corners into the spacer board. The sub frame for the deck is intended to be 90x45 H3 pine My concerns are that the decking boards will expand and contract, and we will be requested to replace the boards. If instructed to install the tongue and groove flooring, I wish to be able to provide a document that supports NOT installing T & G externally.
_____________________________________________________________________________________________________________________________________
Extract From Specification below H.27 VERANDAH DECKING Allow to lay %100x25 Merbau tongue and groove flooring parallel to the length of verandas. Top nail boards with stainless steel nails over %150x50 treated pine floor joists @ 450 cts laid on edge over set down concrete slab, or adjustable steel piers. Lay snake belly flashing over each joist prior to fixing flooring. Overhang final board with bullnosed edge and trim ends of joists with %100x25 hardwood board. Mitre boards in verandah corners and finish mitres against an %75 x 25 trimmer. Sand to 80 grit and apply 2 coats Cutek Extreme CD50 Clear.
Tongue and groove flooring was often installed on verandah floors in earlier times but is not generally recommended today. Timber decking is installed with spaces between the boards to allow for swelling and shrinking in responses to changes in moisture content. Flooring is kiln-dried to a moisture content suitable for interior use, and is likely to swell if exposed to rain or high humidity outdoors. Tongue and groove boards might give satisfactory service if there is a significant roof overhang to exclude rain, the boards are coated all round prior to installation with a moisture excluding finish, and they are spaced apart 1.5 to 2.0mm to allow for swelling. It's also preferable if the verandah is not facing the prevailing weather. If the verandah floor is installed over a concrete slab set down, as per specification, the concrete should be dry before the flooring is installed. We are not familiar with "snake belly flashing" but perhaps that is to prevent moisture rising from the concrete. We suggest you draw these factors to the attention of the architect, since satisfactory performance is not guaranteed even with the precautions outlined above.
Has anyone had any experience with using a product called Firecoat to retrofit an existing residence to bring it up to the BAL 29 requirements and/or had a building surveyor approve the use of the product to coat hardwood species that aren't listed as BAL 29 compliant to meet the standard?. The product has passed BAL40 rating testing however it seems very difficult to get acceptance of it as part of a cost effective solution to bring old buildings up to the requirements.
WoodSolutions has not conducted testing of the Firecoat product and has no experience of its use. However, if you can obtain a certificate from a recognised testing laboratory, there shouldn't be any problem in achieving building approval. The Firecoat website states that Firecoat is "accredited with a BAL-40 rating by independent body, The National Association of Testing Authorities (NATA), Australia's leading accreditation body." This statement isn't quite correct. NATA provides accreditation of organisations that can perform testing, NATA doesn't actually do the tests. No doubt this is just careless wording and presumably Firecoat can provide a certificate of performance for your building surveyor. If the product achieves BAL-40 then it also achieves any lower rating such as BAL-29. As you are probably aware, fire resistance is only required for elements that are exposed to a potential fire, not for internal timber. BAL-29 areas require "bushfire-resisting timber" for exposed elements. If the hardwood in question happens to be one of the seven timbers in Appendix F of AS 3959 that are rated bushfire-resisting without treatment, then a fire retardant such as Firecoat is not required. Otherwise, any timber can be made bushfire-resisting by the application of a fire retardant coating that complies with AS 3959, Appendix F.
