Looking for advice or comment on using PT 6×6’s for pole barn structure. I know everyone uses them for these buildings, something just doesn’t seem right in using wood below grade to support an expensive building.
What PT rating would you look for on posts? Any other suggestions would be appreciated. thanks
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Replies
the required treatment retention is .60.... as opposed to ground contact which is .40 as opposed to regular pt which is .25
we always use 4x6 instead of 6x6..
and if you don't want to bury your poles, you can always go convetional and go concrete foundation or commercial steel
Mike gives good advice.
Just out of coriosity what, state/providence/etc do you live in? Different areas have different types of PT lumber...
Most of the commercial pole builders (aka Morton) are using 2X6's glued and stainless nailed together to form poles 5 1/2 X 4 1/2. The bottom, below grade sections are treated to .60, and there is a transition a few feet up from treated to non-treated 2X6s, kind of like finger jointed.
http://www.mortonbuildings.com/ValueInTheDetails/Materials/Timber.shtm
I've got a 15 year-old 24X30 shop using treated 6X6's. Drilled holes, poured rebar keyed footers, erected and braced the poles with the ridge and headers, formed the beams and slab, tied the #3 & #5 rebar which was keyed into the 6X6's, and poured the slab. The 6X6's make it convienent to use 2X6 framing. 10' walls, and covered in steel. No problems so far. It's built on a post-oak gravel pad.
I'd go with laminated posts instead of 6X6s.
You can preassemble the "base" unit that's only 10 - 12' long and set that as you would a 6X6 post. That way it's a lot easier (lighter) to set and plumb.
Then you can add more lumber to the corners and plumb them up to the height you need. Then run string lines off the corners and take the rest of the posts up to full height.
To make room for the truss, you just cut one of the boards to the correct height for the truss to set on. No more notching 2X6s while you're 14' in the air.
Sure makes it easier to NOT have chains and come-alongs to pull the posts around so they're halfway plumb.
Do a search for Rural Builder magazine.
There are products available that are ten times better than any offered here.
Ask Mike, we had an argument about it sometime back.
Email me if you can't find it.
Eric
It's Never Too Late To Become What You Might Have Been
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Take a look at this site http://www.permacolumn.com .
That's what I was talkin about......way to go!!It's Never Too Late To Become What You Might Have Been
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Thanks. Those permacolumns seem like the way to go. Seems like someone always comes up with a better way to do it.
That's funny I'm the same way just doesn't seem right to put up a $30,000-60,000 building with poles made of wood in the ground. I'm in eastern WA. and it's dry here so it is done all the time, the pole building will most likely out live me. Still I'm looking into a red metal frame building, cost is not that much more.
Jeff
Just finished upgrading my 1992 polebarn by adding a concrete floor. I had used laminated 2x6 posts of .40 CCA (ground contact).in the original construction.
As per the picture in the permacolumn link, I found several of my posts looking like those pictures when I excavated 6" of graval in prep for the pour.
I managed to support/jack/cut out bad, and retrofit with steel and concrete to a similar repaired condition as that link. Then poured the slab! I formed out 6"around the remaining posts to allow for future retrofits as others will fail!
Some things to think about.....
*Most of the local appraisers use a 20 year longevity faactor for evaluating pole barn type structures. I live in a mixed humid environment---40+ inches of rain/year. Pole barns tend to rot at the poles and sink into the ground!
*The new ACQ & Copper Azole treatments use a conservative approach to reduce costs. 5/4 stock is the least treated. 2x receive an equivilent .25 (above ground only). and 4 & 6x's receive .40 (ground contact)
*These are standard...any different than that would be specified by the builder/manufacturer to meet specific conditions, and must be special ordered.
*So today I could not go to my local mom& pop yard or to the local big box and buy ACQ 2x6's that could be used for laminated post construction.
FWIW............Iron Helix