Backyard Aquaponics
A place to discuss aquaponics

What's the verdict?

There is a lot of unsubstantiated (mis?)information/stories/speculation/spruiking/panic about treated pine and about the possibilities of chemicals leaching out of the wood. In CCA, the chromium used (allegedly) prevented the arsenic and copper from leaching, but seeing as CCA isn't widely used any more, it may be a moot point?

[quote user="http://www.apvma.gov.au/products/review/completed/arsenic_faq.php"]From its assessment of the information available, the APVMA concluded that it had insufficient information to be satisfied that the continuing use of CCA is safe for timber used in structures with which the general community (and particularly children) are likely to come into frequent and intimate contact.[/quote]

New methods, LOSP, TanE and ACQ are supposedly "safer", but for whom and over what exposure is this measured? I guess if these methods are "safer" than CCA, but CCA doesn't pose that much risk that it must be immediately banned and all existing structures torn down, then what's the point?

Of course, the perfect solution is to use chemical-free, sustainably grown and environmentally harvested hardwood, but the price difference for some home-projects makes these solutions economically not viable (un-viable (gr?)).

I know a lot people "just don't use treated timber" but they have no proof or evidence on any possible effects and base their decision purely on feeling or dislike without merit. I trust some of the results from CSIRO and other such responsible studies, more than some of the negative (it's unsafe) results from some enviro-nazi lobby group consisting of a few people with vested interests or studies with completely the opposite results from the companies who are trying to flog their product stating it's perfectly safe (unless you burn it or eat it!)

If you're not going to use treated timber for your outdoor projects (for whatever reason), what do you use instead? Are the glues and agents used in recycled composite materials any more/less harmful?

Anyway, what's the AP consensus on using treated timber in/around AP systems? Do you use it? Would you use it? (Unemotionally) Why, or why not?


Scott

P.S. If you have collected studies/results/evidence from places (other than the obvious URLs) then please provide links or post that too.

The main reason i don't like pine is that it warps too much. You have to buy the thick pieces. Cost more $ and for the same money you can get some besser blocks and/or steel.

Treated pine even smells toxic... Im not to sure if its safe or not.???
I built a frame to surround my ibc out if treated pine(should also use screws suitable for treated pine).

Above water level I used kalumpa(spelling) hard wood, for lid frame and decking lid.im going to use it to clad the sides aswell. Its only a few dollars more than treated pine decking. Think kalumpa is $5.60 a LM. does add up though. I looked at composite decking but that was mega pricey,and no one could tell me it wouldnt leech.

Sent from Brett's Galaxy using Tapatalk

The treatment that makes treated timber last longer is a chemical or number of chemicals that are poisonous to things that eat wood. Mostly this is fungus and insects. The treatments are so strong and toxic that they are meant to make the wood last for 25+ years. The reason that treated timbers eventually rot is because that the chemical that used to poison the fungi that is responsible for the wood decaying is no longer present in the wood.

So the questions I'd ask are:

1. Do you want to be handling, cutting, touching, breathing (from saw dust), etc. a material that is so toxic that it is meant to kill fungi and insects for over 20 years.

2. When the wood starts to rot and is essentially getting eaten by fungi where did all the poison go?

The thing I would tell you is that treated pine does not last very long. It last a lot longer than untreated pine but I've seen many installations where treated pine is falling to bits after as little as 8 years. I've seen a stack of examples where treated pine was failing after 15 years. I've only seen a few examples where the treated pine was lasting as long as the manufacturer said it would (25+ years).

Personally I would go for safer alternatives. Out west I don't know what is available to you but on the east coast everyone should be able to get cypress pine. Rot resistant, insect resistant and generally a good structural timber.

I'm fortunate that I have access to Californian Redwood which is even better but the only person I know that you can buy that from is me and I don't have that much to sell.

What Stuart says is true,
However in WA if you want to use wood there isnt much choice atm, hence the reason all our houses are getting built from pine treated in various ways.

So the choice is, change to steel/concrete or other materials,

Or use treated pine sensibly and manage the risks.

There are various types of treatment available for diferent uses, make sure you know what the diferences are and use the right stuff in the right place.H6 CCA will last a hell of a lot longer than 25 years, even with full immersion, but I dont recommend it.

DONT use treated pine if its going to be immersed or have contact with water draining into your system obviously. But I have used it under my GB's and for the legs and the frame over the whole thing, theres really no water/moisture going from the timber into the FT, so as far as im concerned its safe.

A cover over the FT made from CCA is debateable, I would guess there are plenty around, there may be rain water etc washing chemicals into the water, but if its not enough to kill the fish, its probably not going to harm you, although the real concern I guess is the long term buildup in your body, and im not qualified to answer that one, im just a Carpenter.

I guess its something to be aware of and everyone make their own judgement.

A concern with using any timber to constuct GBs is that you can get condensation on the outside of the GB particularly if you are using a liner. Plus GH tend to/should have quite high humidity so even timbers that don't have contact with water can be prone to rot which is why you should use rot resistant timbers inside the GH.