Precasting my own concrete columns for pole barn?

Tompet · Feb 27, 2014

If you go to the Permacolumn web site there is a video of the fabrication procees of the product. The brackets are attached to 4 or 5 rebar (special type is their claim) which runs through the length of the pour for sheer strength. I priced these out a few years ago and for a 5' column with a laminated 12' 6x6 pre-attached they were $140. each.
If I ever get my small barn project off the ground I would still lean towards using these. I do not know current pricing. IMO, it seems to be a good product.

Egon · Feb 27, 2014

Just curious on the concrete mix you will use and the size of the aggregate?

bucktaker · Feb 27, 2014

Another option is to drill the holes, concrete as a footer, set the PT pole then backfill with crushed limestone. It packs and drains. The better builders here will do this if you request it. This is how I have been setting my fence posts and they are locked in solid.

doxford jim · Feb 28, 2014

When I built my double car port I used the 12" diameter sono tubes as previously described. I used my post hole digger (12" auger plus 24" extension) and drilled down as deep as I could. The sono tubes fitted into the holes nicely and they were all 4'6 between 5'0" deep - local code calls for 4'0" below grade for frost.
I made my concrete columns stick out 16" above grade and put in three pieces 5/8" rebar 6 1/2 ft long into each footing. I filled each sono tube to the predetermined height ( took around 11 bags of concrete in each tube 3,000lb mix)and added a 6"x6" Simpson post base on the top. The poles I used were 6"x6" treated lumber eight feet long. With the other framework and roof trusses, the whole lot came together nicely.
It is now over two years with a temporary roof covering and all looks good.. This coming summer a metal sheet roof covering will be installed.
I know this does not compare to what you are attempting, but might give you something to think about.

doxford jim · Feb 28, 2014

Oooops, I forgot to mention that I used 60lb bags not the 80lb others have used - my old body couldn't take any more than 60 lbs at a time :-(

jel1988 · Feb 28, 2014

Precasting you concrete posts will be a waste of time and effort. Concrete is cheap. The poles in a pole barn would be considered a pile type of foundation. The depth a pile is set is determined by the frost line and the load the pile will support. The friction of the dirt on the surface of the pile is supporting the load. Sonotube is designed so the frost cannot grab the column (normally resting on a footing) and jack it off the footing. If you precast small piles the weight of the building and snow may push it into the ground. I would recommend just augering 12" (min.) holes every 10 to12 ft and filling them with concrete a piece or two of rebar never hurts. Set up a small form at the surface to extend the concete 6" above grade and put a metal connector in the attach your post. If you mix your own concrete measure the water carefully the more water the weaker the concrete. One 94 lb bag (1 cubic foot) plus 4 cu/ft of stone plus 3 cubic feet of sand should be your mix. Out of this amount of material you will get about 6 cubic feet of concrete. If you require more than a couple yards a ready mix truck makes sense.

oosik · Mar 9, 2014

Dig, auger etc a hole where each post will be to the depth required for footings in your area. Fill each hole with cement and extend the hole 12" to 18" above ground with sono tubes. Fill the sono tubes and place whatever type of post connector into the wet cement on top of the sono tube. Let it harden and you are set to go.