I don’t have tons of experience with concrete – I need to make a 2’x2′ footing with a 10″ x1′ sonotube pier on top of it. My thought was to run rebar horizontally in the footing and pound 2′ rebar 15″ into the ground where the sonotube would go, locking the concrete in the sonotube with the concrete in the footing.
Any problems with rebar sticking out the bottom of the footing into soil?
Not looking to get flamed, just information from more experienced folks. Thank you.
Mac
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Replies
It's not supposed to be done that way. The rebar will rust. Steel expands approximately 7 times its volume as it rusts and could split the concrete. You should keep the steel at least 2 to 3 inches from the exterior of the concrete. This retards the rusting of the steel.
Since your footing is so small, I'd do it this way. Have all your rebar pre cut. If you are not protecting from uplift the vertical rebar does not need to be bent at the bottom. Fill the footing form 1/3 full then lay the horizontal rebar. Fill it up to the top of the footing form (bottom of sonotube), insert the vertical rebar, then finish placing the concrete to the top.
Thank you very much. Good idea and I'll build it that way. Something in the back of my mind was saying that my thought was off, I just didn't know why. That's why I belong to this forum.Mac
You can get stainless steel rebar, but it's way expensive.
or epoxy coated
but it's way expensive
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The conventional approach is to use small pieces of concrete with steel wire sticking out (here they're called "dobies") to support the bars off the bottom of the hole. Get all the bars in and wired together, then place all the concrete at once.
-- J.S.