Round shape

[Mike D]

Re: Round shape

Ok-

So I am digging the foundation. What type of concrete do we use? Is this just normal stuff at HD, or do I need a high strength type? I was going to use bags and rent a mixer. Not knowing exactly how many bags I will need, and not wanting to run out mid pour, I was going to over buy with the intention of using what I didn't need on the foundation for the hearth slab (will this work?)
-Not to ask the same question twice, but does one use normal concrete for the hearth as well as the foundation?

Thanks,
Mike

[dmun]

Re: Round shape

but does one use normal concrete for the hearth as well as the foundation?

Yes.

I was going to use bags and rent a mixer. Not knowing exactly how many bags I will need, and not wanting to run out mid pour, I was going to over buy with the intention of using what I didn't need on the foundation for the hearth slab (will this work?)

This will work fine. Remember to add your water first when using a concrete mixer.

Here's a little tutorial I did to explain concrete mixer use:

http://www.fornobravo.com/forum/f6/c...asics-790.html

As far as quantity, Sakrete has a calculator:

Product Calculators | Sakrete

[azpizzanut]

Re: Round shape

Hello MikeD,

Go to HomeDepot.com and click on Building Materials. They have a calculator that tells you how many sacks of cement to buy based on the size of the slab X 4 inches. Also, shop for special pricing. When I bought mine they had bags of high strength cement priced same as standard cement.

Cheers,

[Mike D]

Re: Round shape

For the base pea gravel or crushed rock?

Pea gravel is slightly more expensive but you don't need to compact it. Any other differences?

Thanks,
Mike

[Neil2]

Re: Round shape

"For the base pea gravel or crushed rock?"

Use crushed rock. (Sometimes yards have something they call "road mix" or "road base" which is good as well.) What you want is something that is well graded, i.e. that has a mix of different sizes. Pea gravel is all of one size and is generally used for drainage situations not as a structural support.

[Mike D]

Re: Round shape

Pea gravel is called for in the plans, right? Is it a bad idea to use pea gravel?

[dmun]

Re: Round shape

Pea gravel is rounded, crushed rock is angular, and is more likely to stay put. For this application I don't think much more than walking on it is required in the way of compaction.

[Mike D]

Re: Round shape

Ok- so after I calculated how many bags of concrete (about 50), I looked around for a uhaul concrete trailer place (about 1 yard). I found 2 places somewhat close, one was just a big open non rotating trailer, the other turned as you drove. They were about the same price, just different directions.

My question is about the strength of the concrete compared to using bags.
The uhaul places use a concrete rock mix and then add 5 bags of portland cement, the psi around 2500 after 28 days. The bagged mix says it has a 4000 psi. The price of bags is about the same as a yard of mix from the uhaul places.

-Do I need the 4000 psi with all this weight? I am planing on using lots of rebar and wire for reinforcement.

Thanks,
Mike

[azpizzanut]

Re: Round shape

Hi MikeD,

If 4000 psi mix is what you'd prefer then ask the supplier to add more Portland, it's only a matter of $. A consideration is set-up time since some concrete is "fast-setting".

My wife and I poured four oven slabs (top and bottom x 2) with the help of our son to lift and load the bags of cement. It really doesn't take long and it was more fun than I anticipated. Make it a family affair or invite some friends over to help. We bought 60 pound bags of 4000 psi at HD and they were easy to handle. We have a 3-bag mixer.

If you're going to cover most of the slab with brick or tile then you don't need to do much trowel work except for the parts that might be viewed. The entire top slab for one of my ovens is completely covered, nothing needed for it except leveling with a screed. The bottom slab has a 24" landing that was floated smooth and then edged. Looking back, the slabs were easy. The hardest part (on my aching back) was bending over to tie all that rebar. After I learned how to wrap the wire even that part became easy.

A good rule to remember when doing concrete work is: "Pour concrete in the morning and finish it in the afternoon". That's been good advice in my experiences working with concrete. If you get started too late then you end up finishing in the dark.

Best of luck,

[Mike D]

Re: Round shape

Azpizzanut-

Thanks for the reply.
Is there a special way to tie rebar?

[azpizzanut]

Re: Round shape

Hi MikeD,

Here's the method I used. Also, Google for "How to tie rebar".

How To Tie Rebar and Place in Foundation For Concrete Pads | General Remodeling | Howcast.com

Cheers,

[Mike D]

Re: Round shape

I got these 3" dobbies but they look a bit tall. Should I have gotten (or return them) the 2" ones. I started to lay out the rebar and with the 3" dobbies the rebar would not be in the middle of the slab (with 2x6 lumber is really 5 1/2 and the ties on the dobbies lifts the rebar up a bit more).

Any thoughts?

[Neil2]

Re: Round shape

Try to get in the middle to bottom third of the slab.

[Neil2]

Re: Round shape

How To Tie Rebar and Place in Foundation For Concrete Pads | General Remodeling | Howcast.com

Re-bar placement fail.

The rebar should have been continuous, bent 90 degrees 4 times with one side overlapped.

Take anything you see on u-tube with a grain of salt.

[Mike D]

Re: Round shape

So I poured the slab over the weekend. It went fairly easy with the help of a few people. I rented a mixer and a got 55 80# bags of concrete. I have 8 left over, but I will use them to fill the blocks (I did not want to run out). Not as hard as I thought it would be. Hopefully everything will set level, the weather here is overcast and is going to rain off and on this week.
-The first pic of the rebar was taken by my 7 year old before the wire sheet was tied in (I forgot to take a picture right before the pour).
-The Oven will have a grill area next to it with a prep area between them, That's why there is a strange shape.

-Do I need to keep it covered with plastic if it is raining?

Thanks
Mike