Stupid question - rebar spacing for concrete slab Casa 100 oven

[WineOClock]

Starting my build for a Casa100 oven and had a question I'm hoping someone can answer. The slab will be 73" by 66" (roughly 5" thick) and I've started to layout the rebar and get all my ducks in a row before pouring. I have read the instructions from FB and will be doubling up the rebar on the outer edges, with the rebar 4" apart. My question is what spacing do I set the rebar at for the rest of the slab? every 12"? every 8"? Any help is greatly appreciated!

[Chach]

I personally don't think it matters too much but 8" spacing is the norm for structural slabs.


Ricky

[WineOClock]

Thanks for the reply! Had some setbacks over the last few months, but getting started on this again. Was able to do a bit of reading and I'm not entirely convinced that the base needs rebar throughout. The plans say 2 pieces of rebar on the edges 4" apart, then mesh for the middle. Has anyone done their slab this way? Any drawbacks?

[NCMan]

What kind of a base will the slab be on? Is it good and solid? Generally, for a slab that thick, I'd consider 5/8" rebar (#5), but 1/2" (#4) will do fine. Keep them away from the very edges, maybe 3-4 inches. I'd say maybe in a 12"-16" grid, each way. I'd probably skip the mesh, but it can't hurt. Be sure to tie your rebar together to keep it from shifting and also be sure to lift it up off the base as you go to get it roughly in the center of your slab or a little lower. As for whether you need it or not, that's for you to say. If you have a really good, solid base, you can use less. Me personally, I'd use it.