I just saw this other post about a deck and it's wood posts and
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
Location Minnesota - rain and snow.
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,
one day guys in moon suits may be removing outdoor wood all over the
some outdoor wood contains cancer causing chemicals. stay tuned for
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"
It'll probably last till the kids outgrow it. I'd plan on tearing it down
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.
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
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.
Tony - Out of curiousity -- are they *still* building them out of
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.
how pressure treated lumber works:
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.
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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