| Since I raise bromeliads, which are very sensitive to copper and other metals used in pressure treating lumber, I have become very leery of PT wood. As a result, when the shade structure was built over my pond I used western cedar, a rot-resistant wood. (Not rot-proof by any means!) The uprights, since placed in the ground in concrete, would be in regular contact with moist soil and irrigation spray, so those had heavy coats of water sealant applied. This will retard, but not prevent, eventual rot setting in. The wood "roof" pieces crossing the pond had no form of treatment. I did not want anything over the pond that might leach any adverse substance. I believe I am overly cautious, and perhaps a bit foolish since I've consciously had a structure built that will need to be replaced when rot occurs. That may not be for 7+ years, or it may begin to rot in just a few years. In Florida wood does not last as long as it does in more temperate climes. But I'd rather replace it in the future than have a chemical poisoning issue along the way. Like I said, I'm probably overly cautious. But, I'll do the same when the time comes to replace it. |