>I'm bolting together some treated 4x6s to serve as the foundation for a shed I am making. Man, is that wood wet! Free water bleeds out just from the pressure of the auger bit (I am using a brace, so this isn't too OT). Is that stuff still green when they treat it? Also, if I bolt it together when it is that wet and then leave it outside to freeze all winter (taking up a LOT of room in the shop) will it expand and crush the wood fibers to an extent to which it would cause any problem?
>As far as I know, treated lumber is either green when treated, or has been kiln dried but is still too wet to be stamped as KD. Hopefully somebody with lumber treating smarts will jump in here, but as I understand it, the treating process has to saturate the wood completely with a water based solution. If it wasn't wet already, it is after treatment. I don't know if treated lumber can be kiln dried after treatment, but I can see that the emissions problems could get complicated to do so.
>I don't think that you'll have any troubles with freezing.
My experience with 4x4 PT posts, however, is that they want to twist like crazy as they dry out. Two years ago I built a fence & garbage bin - the only garbage bin on the block made with fox-wedged mortise and tenon joints :). Many of the fence posts have twisted ~5-10 degrees after they were installed. My bin is now distincly a parallelogram due to this twisting. I also had to adjust both of my gate latches due to the twisting.
I don't know if I had bad luck or if this is common. I hope that you don't experience a similar problem with your foundation. If it is critical, I might let the 4x6's dry out over the winter and build the foundation in the spring.
I also built a base (foundation) for a playhouse out of 2x6 PT lumber two years ago, and didn't have any problem with this material. It was simply screwed/nailed together with 3" screws and framing nails.
I was amazed at how wet the pressure treated lumber was - I chopped the mortises in the garbage bin by hand and there was water (or toxic arsenic slime?) spraying out with each mallet blow.
>I see you got some of the same pretzelwood that I got for a project last year. Carefully chopped mortises, and then watched as they twisted out of alignment with each other as the summer progressed. The 4x4s are the worst!