Pole Building Post Selection

[blair683]

I am about ready to start building my post frame garage. I plan to order the materials tomorrow or Tuesday and dig holes on Thursday. I plan to make my holes 3.5' deep and put 6" of concrete in the bottom to sit the posts on then encase in concrete after that. The first question I have is in regards to the hole diameter. The biggest auger my local rental shop has is 12". Do you guys think a 12" hole is big enough for 6"x6" posts? My other question is about the post quality. I have gotten quotes for the pole building kit at Menards and my local lumber store. Both kits want me to use 6"x6" on the corners only and 4"x6" posts everywhere else. They also use the cheaper #2 posts. This link here is the post I originally wanted to use. https://www.menards.com/main/buildi...22330150-c-13131.htm?tid=-7687063496855865664 It is obviously a lot more expensive. Menards kit wants me to use these https://www.menards.com/main/buildi...22454018-c-13131.htm?tid=-7687063496855865664 Should I use the ones menards is putting in the kits or should I buy the ones in the first link. My building will be 30' wide by 27' deep. The 4:12 trusses will be on 2 foot centers spanning the 30' width. Twelve foot walls.

 

[buddyboy]

you might want to dig your holes 4 1/2 feet deep with 6 inch pad for the post. that gives you 4 feet in the ground plus 12 in the air for a 16 foot post.

the more in the ground the better for sheer strength, and depending on what part of ohio you may need to go that deep to keep the bottoms below frost.

6x6 for the corner and 4x6 for the walls are fine.

only problem with a 12" hole, it may be too small for your foundation pad under your posts.

find another rental place that has 18" drill

usually the lumber yard will give you drawings with your 'kit' study them and also stop in to other lumber yards and get quotes for their "kit" and while your getting the quotes see if they'll give you drawings so you can compare and see if there are differences.

usually the lumber yard will ask where you will be building it so they can pull up the correct drawings for that counties building requirements.

good luck

 

[blair683]

The one good thing is I don't have any building requirements. I live in a small town that don't care about much of anything. I already received my building permit and I asked if there was any requirements or inspections. They said no and didn't seem to care about anything but my $30 for the permit.

 

[buddyboy]

then it's up to you to guess what the requirements should be.

snow load?
wind
termites
floods
frost

last thing you want to do is buy a 'kit' and find out it won't handle the snow load for your area.

another option is to look at some older (+20 years) pole buildings in your area, and see how they were built.

 

[Randy in Maine]

Another big issue is "straight line winds". Do your homework.

 

[blair683]

The kits at Menards, Carters, and our local lumber yard are designed for our area. Well atleast they are suppose to be. I think I will just do the kit. The post quality has me concerned. I'm guessing they know what they are talking about though. They sell a ton of these pole building kits.

 

[classic boost]

... then encase in concrete after that..

don't encase the post in concrete. it holds water between the post and concrete and promotes rot.

 

[blair683]

don't encase the post in concrete. it holds water between the post and concrete and promotes rot.

Ugh, I have been debating how to set the posts for awhile. It seems people say that they encase them in concrete and they last a life time. Others say they have seen them rot off in concrete. Then people say they have lasted 50 years just backfilled with dirt and others that say they rotted off that way. I was worried about the posts sinking when only backfilled with dirt/ gravel. I'm at a crossroads with what is the right way.

 

[sberry]

You need better plans, the corner posts can be smaller, the ones in the center carrying truss load need to be larger. A center post supports 4x the load a corner does.

 

[classic boost]

Ugh, I have been debating how to set the posts for awhile.

places null warranty if posts are in concrete, so it's definitely not the way to go.

 

[gungatim]

don't encase the post in concrete. it holds water between the post and concrete and promotes rot.

agree. around here you either put dry dement in the hole first (it will set over time and act as a pad) or drop down a pre-cast pad first. backfill with sand/rock.

IF and only IF you ever need to replace a post, it is much easier to do without digging out the old cement covered post, or sistering on a new one can be done as well. have personally witnessed many poles encased in cement completely rotten around the concrete...laminated posts fare even worse.

 

[86turbodsl]

I've dealt with some of your problems. I do not encase in concrete, it does promote rot. I have always used either dirt or pea gravel. Per my local inspector. I usually drill a 12" hole, then shave the sides a bit to expand, pull the shaved material back out with a post hole digger, then pour a concrete punch pad in place. I don't like to precast them, makes it too hard to get down into a hole. I did have a couple of trenches 4' deep made once when an excavator was nearby, and precast punch pads then set the poles and arranged bracing to hold them while i backfilled, but it was a delicate dance to keep things from moving around. I wouldn't do it again.

 

[blair683]

So if I back fill with sand and gravel, should I use real small gravel? I just brace up the post and leave all the braces on until the grade board and header board are on that way the posts can't move?

 

[ToolmanGary]

Just thought I'd mention, If your buying your package from Menards they have their 11% sales usually once a month, they will send you a gift card that you have to spend in their store. In my area Lowes and Home Depot will match the rebate when Menards has it going

 

[buddyboy]

if your soil is hard packed clay then just use that around the posts, make sure to take your time and really pack it in tight, 3 to 4 inches in the hole then tamp down.

the reasoning is to eliminate air around the buried part of the post, most of the time the original soil is best as long as you pack it in tight to get rid of the air. think of it as returning the ground to it's original form except now there is a post.

if your soil is sandy then adding a little crushed stone might help 'tighten' it up a bit, but the goal is to remove all air pockets.

putting gravel around a post in the ground thinking it will keep water away from the post will only work if the surrounding soil is more porous than the gravel. water likes to go down hill and also to the path of least resistance. if you dig a hole and fill it with a lower resistance material than the surrounding area you will create a water well.

concrete around the post, like others have said, is not a good idea either. at first it will appear you made the strongest post known to man, then a year or two down the road as the concrete shrinks and the post shrinks your post will be sitting in a concrete 'bowl'

remember air+water+wood=rot and it just takes time

round stone will never pack that is why it is used in drainage applications, crushed stone will pack.

during your build process (and even down the road) there is nothing wrong with re-tamping your posts every few days to really get it tight.

good luck