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Discussion Starter · #1 ·
Need to build a 12 x 12 shed foundation, I guess 4" thick. Comes out to 1.78 cubic yards, or 80 bags @ 80 lbs each.

My question is what kind of concrete do I need? I notice all different kinds when I go looking and the price difference adds up pretty quick. I don't want to blow a bunch of extra money on some variation I don't need.

Also, what about rebar and steel support? I've noticed most people don't use it for sheds. Something about the size of the pad not being big enough to require it.
 

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Tim,
I would never dream of trying to mix that much by hand. You will tire out before it is all poured. I would never, ever purchase concrete mix from from a box store. That crap has been laying on the ground or sitting outside getting all kinds of moisture. And you never know the age of the mix. And you may run shy, which is never a good idea. Order it to be delivered. Order 2 cubic yards if you are that close. There will be some that spills, some that does not come off of the truck, and some that just not look good and you shovel it out. Always better to have a little too much.


I would lay down a good layer of compacted gravel, depending on what you plan to set on the pad as far as weight, I would go as deep as 6 inches if you are parking a vehicle. And then a good 4 inches of concrete. I would not fore go the rebar for any concrete pour. I use it always. I also only use fiberglass rebar. Never any rust with fiberglass. Rust will cause the concrete to crack. Fiberglass is very stable. You can use 4x4 square lathe. I cannot think of the exact name at the moment, but it looks like fence wire. The sub under the concrete is the most important part. Do that well and correct, over kill is always better in this situation.


I poured my workshop of 30x60 feet using 6 inches of concrete fiberglass rebar and 8 inches of gravel and gravel dust. I ordered re-enforced concrete from the mixer, they added horse hair and fiberglass feathers. I had a large dump truck filled with dirt roll over it, and nothing happened other than it got dirty. I had a company come in a polish the floor once I completed the building.

Concrete is one of things that you can never go back and touch up, or repair. You must start all over when there is an issue. Always better to do this right the first time.
 

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For GAWD sake, he's pouring a 12x12 shed, not another hoover dam. If 80 bags is too much to mix, do it in 3 or 4 shots with a cold joint and you won't need any expansion cuts. As old as i am i could mix 20 bags 4 consecutive mornings.:biggrin2:
 

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Discussion Starter · #6 ·
Thanks for the replies fellas. I do have 2 grown sons that owe me their life (a few times over no doubt!).

I was still going to call the concrete company and see how expensive to bring 2 cubic yards of concrete and compare.
 

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You want to order ready mix? Around here they have a minimum order, which is more than 2 yards.
You and your muscle boys can do it in a day and a half.
I would use 50/50 mix, have the supply house dump it near the site, then use a concrete mixer.
For reinforcement steel, buy 3 sheets from the supply house, you don't need rebars. HD has them too.
 

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Discussion Starter · #10 ·
You want to order ready mix? Around here they have a minimum order, which is more than 2 yards.
You and your muscle boys can do it in a day and a half.
I would use 50/50 mix, have the supply house dump it near the site, then use a concrete mixer.
For reinforcement steel, buy 3 sheets from the supply house, you don't need rebars. HD has them too.
Ok...so what is 50/50 mix? Sorry, I don't have much experience in concrete at this point.
 

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Same here but the minimum number of yards means you don't pay a delivery fee, they will bring out less but they add on the delivery fee.

Same here as well. Delivery fee is about $50. Add that to the $120/CY for the concrete, and you're looking at $290. I doubt you can find 80 lb bags of concrete mix for less than $3.63 each in most places.


No access for the concrete truck would be a reason to mix on-site, but if you can get the truck to within 30' of the slab, you won't even need a wheelbarrow.
 

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Tim Koupe,
50/50 is sand and pea gravel mix, just add cement and water and mix for at least 3 minutes to activate the cement.
You can also buy sand and 3/4" gravel separately, and mix them with cement and water to create what you need.
You get them all at a building supply place.
 

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Its nothing to mix 80 bags for post holes etc..

But for a 12' x 12' slab,: :vs_laugh:


Do yourself a big huge favor a get the small truck from the plant. Even then you will find it challenging.
 

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Discussion Starter · #15 ·
Thanks all. I priced 2 cubic yards delivered by a concrete truck and depending on who I use, it's anywhere from $320 to $375. Either way, that's a great price and I'm pulling the trigger on that.

All help appreciated, thanks again.
 
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