rotting desk posts - question about the wood

I just saw this other post about a deck and it's wood posts and wondered....
I built my kids a tree house and sank 6x6 treated posts in the ground to support it (3 feet down, no concrete). How long will these last? The wood is 'green' treated and purchased from Menards - which isn't a 'industrial' lumber yard. (I've been told treated lumber varies in quality)
Location Minnesota - rain and snow.
Thanks
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Some is rated for 20 years ground exposure.
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Impossible to know, have seen some begin falling apart in 5 years, some may last 20 years.
The EPA is looking at listing treatred wood as a hazardous material, like asbestos.
one day guys in moon suits may be removing outdoor wood all over the nation.
some outdoor wood contains cancer causing chemicals. stay tuned for futher devlopments
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It cant be all that poisonous. I thought my treated wood fence would be horse proof. Horses chew up soft wood. I was wrong. The horses chewed right thru several treated boards. They are fine. I cant say the same for the fence. I finally had a local sawmill make me oak planks. What a pain to work with..... But no chewing. Horses dont like hardwood. I dont like working with it.
And just remember, EVERYTHING causes cancer. Particularly SEX. If everyone stopped having sex, cancer would be completely eradicated in about 100 years.
And whatever you do, never burn treated wood, except in a fire.
(OOPS, I screwed up again.... I heated my house with the remains of the horse chewed treated boards for several days this winter). I think my woodburner is lined with asbestos too..... Geeezzzzzzz, I'm getting scared now.....
If you're not afraid yet, just wait till Memorial Day, I predict there will be another terrorism alert (just like every holiday, including the Superbowl). If you keep the citizens living in fear, they will submit to anything.
ALWAYS BE AFRAID - Signed "George W. Bush"
--------------------------
wrote:

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Best to ask some one local. I do not have much rain and no snow where I live.
Some of the green treated lumber was poisonous. Better check to see what they use for the treatment.
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If you eat it. Do your kids eat wood? I "recycled" some wood 5 years ago to build a fort; so I don't know how old it is, but it looks brand new, and nobody gets more snow than Rochester NY!
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when you sell the house, though. People get real silly about treated wood on play structures these days. Kid play fort structures, unless on a public playground, don't get a lot of stress, probably about like a fencepost.
aem sends...
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standard 6X6's from Menards aren't rated for ground contact. How long they last depends on how wet your site is, etc. Longer in dry sand, shorter in wet clay. I'd guess they'll last plenty long for a kid's tree house.
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werwer wrote:

At least until your kid does not want to play in the tree house, LOL. Just make sure water drains away from the post. Up here in Calgary they build basement with treated wood(no concrete pouring). Properly done, as good as concrete.
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Tony Hwang wrote:

Tony - Out of curiousity -- are they *still* building them out of treated lumber?
My parents have a PTF on their house. In the 80's, it was a new and innovative, and CMHC-endorsed. I think they're a wonderful idea, and would consider using one on my own house, even today (I don't lick walls much)... but god knows what the fallout will be if pressure-treated lumber turns into asbestos.
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how pressure treated lumber works: http://home.howstuffworks.com/question278.htm
buffalo ny 1990 fenceposts 4x4 but similar 40" depth but in concrete still fine summer 2005.
old pressure treated playground from the late 70's torn down and removed from a day care still sturdy but worn and still outdoors as pool deck supports here and as a base for a neighbor's toolshed.
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All Menards 6x6's are .60 retention treated, which will basically last forever in the ground. If its a 4x4, which is probably only .4 retention treated, it will last only a fraction of forever. But your biggest problem will be sinking and heaving. Without a footing, this post is going to move up and down, compromising the structure and the tree. The hole should have been at least 42 inches deep with a concrete base of at least 12 inches around. It would not be hard to dig it up and redo the whole thing, but it will probably not just fall over one day; it will just get weaker slowly.
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