His plea was ignored. The change was driven by timber giant Carter Holt Harvey, which wanted to replace chemically treated timber with the cheaper kiln-dried wood it was already exporting to Australia.
Forestry scientists were furious at industry advertising by Carter Holt and its rival Fletcher Forests, which pushed the changeover by claiming that boron treatment gave no more protection against rot than their untreated timber.
Mr Brown said next month's review would also include recommendations over the continued use of copper, chrome and arsenic CCA treatment, which was being reviewed separately by the Environmental Risk Management Authority for health and safety reasons.
Last week Commerce Minister Lianne Dalziel announced the Government's proposals to combat the leaky home crisis by registering all building professionals, protecting home buyers with compulsory insurance and rewriting the Building Code. Structural timber such as these studs must typically have a year durability.
Back to top. Timber with proven natural durability when exposed to the weather Not suitable for use in ground contact conditions. Currently no H1.
Production, storage, delivery and construction and in-use conditions where no risk of fungal attack exists but resistance against borer attack is desirable Internal use only, not exposed to ground atmosphere, always dry H1. Fascias, weatherboards, facings and other painted trim requiring a not less than year durability Exterior joinery and timber reveals for aluminium windows Timber cavity battens.
Suitable for exposure to weather but not in-ground contact. Not less than year durability except enclosed deck framing, which requires a not less than year durability.
Cantilevered enclosed deck joists and associated framing joist trimmers, nogs, dwangs and blocking , decking and outdoor structures, rafters exposed to the weather, exposed subfloor framing, uncoated or stained radiata pine weatherboards and trim, fence rails and palings. CCA Copper quaternary including micronized copper quaternary Copper azole including micronized copper azole.
CCA Copper azole including micronized copper azole Copper quaternary including micronized copper quaternary. A nonprofit organization known as the Environmental Study Group had people take samples of treated wood found all around Washington, and in the end they found that there was roughly one ounce of arsenic per every 12 feet of treated wood.
Although there are health hazards to consider, treated wood does have its advantages. As wood is exposed to the natural elements, it slowly breaks down. Moisture is especially hard on wood. If treated, wood can last much longer than normal, but to make sure your treated lumber lasts as long as possible you need to match its treatment level with the right use. Lumber that is touching the ground, for instance, requires a higher treatment level than lumber that is not [source: Viance].
Treated lumber does have other advantages. Many types of treated wood are resistant to insects, like termites, that cause huge amounts of damage and cost home owners large sums of money. The chemicals used in the treatment process are toxic to insects, so any bug that tries to eat its way through a treated support beam will expire.
On top of repelling bugs, treated lumber can also be fire retardant, taking longer to catch on fire and burning much more slowly when it does [source: WiseGeek ]. In instances where treated lumber doesn't touch the ground and isn't exposed, it is relatively safe.
You can also use certain oil finishes to protect treated wood and reduce the risk of it leaching dangerous chemicals during contact [source: Natural Handyman ]. While treated wood has distinct advantages, you might decide that they aren't worth the added health risk.
Yet, if you need something to last a long time and you know people won't come into much contact with it, treated lumber might be the better choice. In general, though, treated lumber shouldn't be used where untreated lumber will suffice. The next time you're working on a project using wood, consider the advantages and disadvantages of both treated and untreated lumber before making a purchase.
That translates to roughly 25 million trees, every year [source: McCabe, Wolfe]. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar.
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