The regulations dealing with external wall cladding are set out in the ABCB Housing Provisions which can be accessed via the relevant website. Section 7.5 deals with timber cladding and focuses largely on adequate fixings and sarking, rather than species. Manna gum and messmate are rated Class 3 durability outdoors above ground according to Australian Standard 5604, Timber - Natural durability ratings, ie. they are not highly durable species. However, neither are some other species traditionally used for cladding, such as Baltic pine. AS 5604 suggests the 'probable' life expectancy of a Class 3 species above ground will be up to 15 years, but much depends on maintenance, local climate, avoidance of water traps and similar factors. We assume your timber will be dried before conversion into a cladding profile.
I'm after the CRF and smoke development rates of Baltic (Scots) pine, but it appears not to be included in the timber flooring tests? Just wondering if I've missed it somewhere, or if you could direct me to where I may be able to find such test results please?
We have CRF and Smoke Development values for a number of timber species, but unfortunately not for Baltic pine. Nor do we know of a source of this data. Perhaps the importer could provide details, or arrange for the required tests.
Your best source of information is a Technical Data Sheet titled Timber Decks - Commercial, Industrial & Marine. It's number 7 in a series published by Timber Queensland, and can be downloaded via this link http://www.dtmtimber.com.au/downloads/TQ_TDS/tds_07_Timber-Deck_final.pdf. Table 4 gives decking board spans under different load conditions. Spans vary according to the stress grade of the timber. Kiln-dried merbau is generally free from strength-reducing characteristics such as knots and sloping grain, and would be expected to achieve at least F22 stress grade. No doubt the timber supplier can confirm the stress grade of available material.
