Rebar in footing

[DannyO]

I'll start by saying I've never poured concrete, but I'm going to get some help from an expert to "finish" the slab.

1. Is it necessary to connect the rebar from the main slab to the footing? In other words, bend a piece of rebar into a L-shape to connect the main slab to the footing.

2. In the footing, is a single piece of rebar sufficient, or do I need to add some cross pieces?


Specifications:
20ftx10ft
4 inch slab
Footing: 8 inchs deep, width is the size of a shovel.
Adding 4 mil plastic liner to the bottom
monolithic

[Rich]

You won't need any horizontal rebar in the footing - especially with that width. But you should have rebar connecting the slab to the footing and your 1 piece of rebar in the footing should be continuous (overlapped 12 times the width of the bar minimum and wrapping continuous through the corners.

[bkrahmer]

If you are pouring monolithic, there's no way for the slab to move separately from the footing. Since it's not very big anyway, I personally wouldn't worry about putting any vertical rebar in. What are you building, a shed? Again, since it's not that big, I would think one piece of rebar in the footing would be okay. I've not heard of running rebar 'across' the footing. For my house, the footings were 9x18, so I did two lengths of rebar down the footing. There's a trick to turning the corner the correct way, but since you're project looks so small, I won't try to ineptly describe it today.

[DannyO]

Thanks for the input Rich and bkrahmer.

bkrahmer - Yes, it's a shed for a few dirt bikes, a walk-behind commercial mower, and other outdoor equipment.

[bkrahmer]

Rich, I'm curious: why do you think he needs rebar to tie the slab and footers together if the slab is monolithic? I don't see why it would be necessary.

[Rich]

Concrete isn't worth a darn in any direction except compression. With a monolithic slab the appendage known as the footer is pretty easy to crack away from the slab with any settling or movement. Right at the intersection of the slab and footing is the weakest point.

[bkrahmer]

That's a very good point. Thanks. I'll keep that in mind if I ever do a monolithic slab.