I think you said you plan on using treated wood for the floor and inside--please look into that and be sure. I've heard that can be dangerous to the occupants.
Thanks, nobes, it's an interesting point. You deserve a beer for raising it; I will drink one for you.
No, I will drink two!
Is Chromated Copper Arsenate ("CCA") treated timber appropriate for use inside a caravan or teardrop? I think it is.
Firstly, why use it? Because the caravan might leak in ten years time. Untreated pine ply starts to rot soon after it is wetted and is composted in three to nine months in some environments. Treated plywood (with waterproof glue, an important point) will last for years, five to twenty years, in the same environments. Less frequent replacement means more environmental friendliness. It hardly costs any more (about 10% on thick sheet of ply). The delay in damage being done gives one longer in which to uncover the problems and rectify it without facing a complete rebuild.
I wouldn't look forward to replacing my floor, for example
Secondly, how safe is CCA? It's not a matter of opinion, it depends solely on whether the copper, chromium and arsenic can get out. This is what the NZ Department of Conservation says:
"A unique feature of CCA is that by a complex series of chemical reactions, the preservative components become fixed in the wood. .....Without any doubt the key issue is that the preservative has had time to completely fix in the wood before it leaves the treatment facility and that it is free of deposits....current research at NZ FRI and elsewhere is in the development of treatment processes which guarantee that these conditions are consistently met”. (NZ Environmental Risk Agency holds a similar opinion)
There are no reported cases of harm to an adult or child in NZ through handling or inhalation of CCA treated timber. It has been in constant use since 1960.
Why no known harm?
Firstly, arsenic is a natural element. It is common in volcanic soils in NZ for example. All bodies are familiar with it, in minute quantities.
Secondly, the arsenic fixes into a compound with the chromium, the cellulose and the lignin in the wood. It leaches only reluctantly.
Thirdly, sealing with paint or varnish takes care of the small possibility of leaching.
A number of governments, under pressure, have made
precautionary rulings against CCA treated timber indoors, or in kids playgrounds, or even generally. And there are reasons, including problems with disposal, burning and the manufacturing process that justify those rulings. But there aren’t vouched cases of harm, other than from people drinking the preservative liquid either accidentally or with the intention of suicide. These rulings are not fact-based, they are opinion based. The Australian Minster, introducing a partial ban, said “I cannot rule out the possibility of harm”. No, he could not. But, then, we cannot rule out the possibility that he is a fifth columnist from the planet Zog
whose strategy is to weaken the earth with confusing and ultimately pointless rulings. I'm pretty sure he isn't, but I cannot rule it out. It doesn’t take genius to see that his position begs the question whether a sensible man would use it in his own affairs if there were advantages to doing so.
In the meantime, it is the far superior material and overcomes one of the fundamental objections to plywood as a building material; rot.
Incidentally, there are probably twenty-five elements and compounds in cars that are toxic to human beings. There are Chromium, Bromine, Chlorine and Antimony in abundance in the cabin of some new cars, and some of them outgas at up to 8000ppm. That new car smell! It's Antimony and Chlorine mixing! Ahhhh. (For comparision, the measured levels for arsenic leaching from CCA are about 3ppm) Fortunately, like the arsenic in CCA, these elements in our cars are generally compounded, bound, or impounded and cannot do us harm and, if they do, the harm is so minor we never, ever notice it.
To sum up, it is my opinion that far more people will be far more harmed falling down caravan steps
than will ever be harmed by CCA timber in caravans, even if we all used it, provided we used it properly and followed the sensible precautions and that. And our vans might last twice as long. I myself think that is significant but I understand that some might not care.
I support everyones right to hold the opposite opinion
or any or no opinion at all. This is just my 2cents worth.
Thanks for reading.