[geno1]

i am building a post and beam deck with 8x8 and 8x10 beams i am using 12" sonar tubes with 3 pieces of rebar in each i dug the holes 4 feet deep but made them wider than they needed to be just so i would have room to align the tubes correctly just wondering by making them wider than they need to be was that a mistake or should i be o.k the holes are approx 18 inchs wide. thanks for help

 

[RickyBobby]

Get the tube centered where you need it, back fill with dirt and you are all set. Trying to dump crete in the tube without any outside support could cause an awful mess.

 

[Ron6519]

I would fill the area around the tubes in 6" drafts and compact them, thoroughly.
Ron

 

[dpach]

Actually, since you have the holes 18" across, I'd first put a wider footing/base in the bottom 12 inches to help with any frost heaving. Most people don't do that since it requires such a large diameter hole to be dug, but you've already done that.

Once you have the larger footing in the bottom (make it our of plywood), place your sonotube on top (of course, cut a round hole in the top of the footing to match your sonotube up to), then back fill the hole. That way when you pour the concrete, it will go through the sonotube, into the wider footing through the hole you cut in the top of the base footing and give you a very stable footing/pile. Or use a BigFoot pile footing that you can buy from various lumberstores/home centers.

These allow the base of the footing to be wider than the vertical portion for a much more stable footing that frost won't bother.