Round shape

[Mike D]

Re: Round shape

Ok-

So I put down the Hardibacker board. I mortared it down because I didn't want it moving when I poured the slab (I hope that is ok). It cuts like drywall, pretty easy, not that expensive (seems like cutting plywood would be the same).

-Here are so pictures of the rebar. It's not all tied together yet, I wanted to see I have any issues that I don't know about (mostly because I have no idea what I am doing). I tried to give the front a little more rebar (as what other said if I was going to forgo the angle iron). I will tie it all together and then lower it to the right height.

-I am going to use 2x8s for the frame in order to close in the sides of the bond beam block, as well as the bottom (and inside) of the front opening.

-I plan on adding support under the board so I don't get any sag or blowout.

How does it look? Do I need more? Did I way over do it?

Thanks
Mike

[azpizzanut]

Re: Round shape

Hi Mike D,

Your work looks good so far. I think you have the right amount of re-bar. Get some spacers to put under the re-bar to assure it is in the middle of the poured slab. I made spacers from small pieces of broken cinder block but a masonry supply store should have correct type spacers available. Your hard work will pay dividends soon because it will provide a solid support for the oven. There is still a lot of work to do but it seems you are doing fine so far.

I fired my oven twice in two days and cooked pizzas and a beef roast with veggies. Everyone raved about the wonderful flavors of the food. You will be doing the same thing soon.

Cheers,

[Muscats]

Re: Round shape

Make sure you dont leave those pieces of timber in their (the oones holding up the Reo in the pictures - they will weaken the slab.

[Mike D]

Re: Round shape

Thanks azpizzanut and Muscats-

Yes I will remove the wood pieces, they are mostly there to elevate it to help me tie it all together easier. I find the concrete dobbies a little bit too tall if I want everything in the middle.
-I was thinking of using small pieces of split firebricks to get the right level and then pour part of the cores of the blocks to set everything. Does that make sense?

-Mike

[Muscats]

Re: Round shape

yes, you can pour the cores first or pour then as you do the slab either way works. pouring them as you do the slab will prob add some strength as it ties the slab into the blocks but it is more work while you are doing the slab if you do it at the same time. the chairs for the reo come in different heights so you should be bale to find some the right height but you can use anytyhing that you would normally put into your concrete. re positioning the reo in the middle i have read that for a slab up of the ground like the hearth slab it is actually better to have the reo in the bottom half on the slab as the stresses are trying the stretch the slab in that area.

[Neil2]

Re: Round shape

"No, are the ovens still there, yes.."

The ones that were buried in volcanic ash for 2000 years are still there.


Mike

Your rebar design and placement is excellent. Most builders do not anchor the ends properly (or at all !) and thus never realize the full benefit of the reinforcing. For anyone placing rebar in a suspended slab on blocks, I suggest you look at the way Mike has done it for a guide.

For placement vertically, go for the middle of the slab. If it was evenly loaded you would want it in the bottom as Muscats suggests. However, the shape and loading of an oven is too complicated for my computer program to predict what part will be in tension and what part in compression - putting it in the middle will do the job.

[Dino_Pizza]

Re: Round shape

Mike,
your rebar and bond beam look really good. Pieces of firebrick will be fine to hold up the rebar. Any chunk of broken concrete block will work, you might have a block left over from the base to break up and use.

Here is an example of what I did before I poured: I put up my 2x8 framing (yours may be wider depending on if your slab is over 4" or if you are pouring more and doing the vermicrete insulation) and I drilled 4 small holes in the 4 boards making up the perimeter form to put wire thru it and twisted a bolt or some piece of strong metal to pull the opposite boards in to each other to counteract the force of the cement pushing out: After cement dried, I just cut it/unwound the bolt and left the wire in the slab.



I saw someone use just this for his pour but I put lots more bracing around it. It was over-kill but not knowing what I'm doing made me do that.

Just a suggestion and pic of what worked for me. Good luck on the pour.
-Dino

[Mike D]

Re: Round shape

Thanks Dino and Neil-

I don't think you need to go that far Neil, I am just following every ones threads. But thanks

Here is a Pic of the rebar in the grill. I was thinking about putting an extra bar in the front, do you think I need it?
-Like I said in past posts, the only thing on the suspended area will be fire brick with no mortar. The brick enclosure will be under the blocks.

Thanks for the tips for the wood form. I will post pics before I pour.

Mike

[Neil2]

Re: Round shape

"I put lots more bracing around it. It was over-kill but not knowing"

I have often heard "I should have braced that more" on construction sites but I have never, ever heard "I put too much bracing on". A form failure during a concrete pour is not much fun.

[Mike D]

Re: Round shape

OK-

-So I finally finished framing the top slab. I used lots of screws and shims and I think I got it level.

-I was thinking of pouring a small amount of concrete to set the rebar in place (not very much and maybe every other core and just about a foot). That way I could remove the brick spacers to have a nice continuous slab (as well as setting the rebar so it wouldn't move during the big pour). Does this make sense?

Mike

[brickie in oz]

Re: Round shape

-I was thinking of pouring a small amount of concrete to set the rebar in place (not very much and maybe every other core and just about a foot). That way I could remove the brick spacers to have a nice continuous slab (as well as setting the rebar so it wouldn't move during the big pour). Does this make sense?

You should pour the slab in one go otherwise you run the risk of the slab delaminating.

[Mike D]

Re: Round shape

What do you mean delaminating? I was only going to pour in the block holes about a foot, not on the top part.

Mike

[azpizzanut]

Re: Round shape

Hello Mike D,

You are doing a really nice job of it.

I used smaller pieces of brick to hold up the rebar in my slab and didn't pour concrete in the blocks to tighten it in place as you suggest. It seemed like extra work and I was confident the brick and rebar wouldn't move. The weight of the concrete and aggregate will hold everything in place if you are careful when placing it in the form. Whatever you decide, please do get the rebar centered in the slab and not too close to the top or bottom. If you are pouring a 4" slab then the rebar should ideally be placed at 2" (the middle of the slab).

Cheers,

[brickie in oz]

Re: Round shape

What do you mean delaminating? I was only going to pour in the block holes about a foot, not on the top part.

Mike

Owwh, only core filling at this stage, then itll be fine.

[Mike D]

Re: Round shape

I am going to pour this weekend. What is the floating sequence?

First 2x4 across the top.

Then a metal float? Or a wooden one? How much time between floating?

Anyone have any advice?

Thanks
Mike