Sorry, but one more question related to my deck footing project.
If I intend to use 8″ sonotube footings, will an 8″ auger bit make a bit enough hole? I suspect I might need at 10″ auger bit which will give me the couple extra inches to play with, and then just backfill the space around the tube.
Opinions would be greatly appreciated.
Thanks
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Replies
If 8" was big enough, there would still be no room for adjustment. I'd go at least 10".
An 8" sonotube might not be 8" dia. They make them in about nthree sizes around 8" so the tubes can be shipped inside each other. The tubes will be 7-3/4, 8, and 8-1/4".
Two thoughts: depending on your soil type, you might not need the tubes. Auger the hole, insert the rebar cage, and pout the concrete. If you need the tube to extend above grade, auger an 8" hole, them hand dig the top 6" a little wider as needed for the tube to partially sit in the hole. brace the tube and pour.
"Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
if you are in a frost area a foot at the bottom stops the post from lifting just finished a 800 sq ft multi level deck using trex and 19 concrete posts using a big foot on each post , 10" sono used 3 1/2 yds 3000 psi concrete with air
this deck was designed by a architect and inspected
drilling holes with augers isn't always as easy as it may seem. it depends on the soil and if you hit rocks, but often the hole ends up being skewed quite a bit from where you start. someone mentioned using a larger size auger which is a good idea. be prepared also dig if you get pushed way off center.
You could be fortuntate and have little problems, you really never know until you drill the holes.
With the soil where I live, it is very easy to enlarge a hole with a hand operated post hole digger. In fact, its not that bad just to dig it by hand, but if I do use a power digger, I borrow one that has maybe a 6" bit and then make the hole whatever size I want.
It depends alot on your soil. My only experience is with the soil in my area.
Without knowing your soil type, I'm surprised that an 8" diameter footing would supply enough bearing capacity. How big is the deck, how many posts will there be, and is it attached to the house? What is your guess of the soil type? How deep do these footers need to be?
BTW - you can just add to your previous thread (discussion) rather than starting a new topic.
Edited 10/20/2007 7:23 am ET by Matt