Concrete Questions

[N80]

I'm starting my 3 bay tractor shed/barn this weekend. This is bare bones sort of thing with a metal shed roof, open sides, dirt floor and I'm trying to do it on the cheap. But, it looks like I might have a little extra cash in the budget and it sure would be nice to have concrete floors.

I know nothing about concrete. And my first problem is figuring out how much I need and how much it will cost and I don't even know how to estimate. If I can figure that out, and if I can afford it, then I'll figure out how.

The floor area will be 34' x 20'. It will need to support my tractor and implements but I have no idea how thick it needs to be. Based on that, can anyone tell me how much I'll need?

How many cement trucks full is that?
How much does a truck full cost?

If I decide to mix and pour my own, how many bags, gravel and or sand do I need?

If all this looks too expensive I might just do the center bay which is where I'll park my tractor. It will be 12' x 20'.

If anyone can help me out with this it would be very much appreciated. As for the how, I'll ask those questions later but I will have access to help/supervision from someone who has done this before.

Thanks.

[MrJimi]

Thickness of concrete will have lots to do with how much and you don't want to do bags.
here is a calculator for you
http://www.concrete.com/calculatorsmaterials.htm
trucks and a good crew is the way to go

[N80]

I found a concrete volume calculator for a local concrete contractor. I did a calculation figuring 4 inches thick and it comes out to 8.4 cubic yards. But the 4" part is a pure guess. I have no idea how thick it really needs to be.

Anyone know how much an average truck carries?

[MrJimi]

Most can carry 10 but some may spill out and 9 is a good number
and make a place for the leftover, if you have any and make sure it is real level.
4" is normal and I went 6" of 3,500 PSI in my building

[crabjoe]

That's a lot of concrete to be messing with bags. Just have them deliver the concrete. Around here it was around $100/yd delivered last year.

Also, don't forget to make sure your soil is well compacted before pouring. Make sure to get rebar laid down too.

Oh... Thinkness wise ... I really don't know but around here, most garage floors are 4-6 inches thick. A friend of mine concreted this pole barn floor and he had them pour 6 inches. He's using it as a garage with a few lifts and what not... But where the lifts are mounted, I can't remember for sure, but he poured footers around 24inches thick for the lifts to mount to.

[N80]

Rebar? Yikes. Hadn't thought of that. Things are pretty stable here so I don't know if I really need it or not.

As for compaction, there are a few inches of topsoil, but below that its dense clay for 2 feet then below that its this hard crumbly stuff that is very compact. I could probably rent one of those thumpers to compact the topsoil.

If I pour it 4" thick that's 8.4 cubic yards and would require just one truck load and set me back about $900 if its $100/yd. But that doesn't include rebar and stuff like that if I need it. So its starting to add up.

In any case, I've got an email to the sales guy at a local concrete place. I'll see what he says. If I can keep it below $1000 I may do it. Otherwise I may just do the center bay...or maybe just leave the dirt.

Thanks for the help guys. I bounce a lot of ideas around on this site and always get good advice.

[mikim]

HIRE IT OUT! that's too big a pour for you to do .. especially since you've never done it before. You need the rebar to hold the concrete together -and I'd highly suggest 10 mil plastic vapor barrier under it as well. It has to be formed up, leveled and squared, plastic down, rebar & wire, skreed off then finished..... too much for one man fer sure - it takes a crew ... preferably a crew that 1. has the tools needed and 2. knows what they're doing. Even doing a small 10 x 10 pad is a BIG job for someone that has never done flat work before. The amount of $$ you'll spend on labor is half of what it's worth. A quick and dirty estimate for concrete is 81 sq ft 4" thick = 1 yd. Lately around here concrete work has been going for about $10 sq ft complete.

[MrJimi]

And you will need a vapor barrier, form boards and the 6"X6"X10 gauge wire to hold it all together. You will have some spending to do, but! do it correct once and not twice half way
and you will have to decide on a floor finish, I went with a smooth finish on mine and it's easy to sweep out
Are you putting footers around the perimeter to support your walls? something else to consider.
Take a drive to your local building department and ask them, they are your friends to help you make it safe and strong

[N80]

No walls to support, so no footers. As far as hiring out the work, that would put me over the top on budget.

I will have help. My B-I-L. He finished the floor of his Butler building and it is three times the size of this shed.

I actually have a bunch of surplus 10mil vapor barrier in rolls in the crawl space of my cabin, so that's one less expense.

Form boards, no problem. I can get all that laid out.

But, rebar and guage wire..... don't know nothin' 'bout no rebar.....so if that is a necessity I'll either have to hire it out or skip it. I'll talk to my B-I-L. He always pushes me to do this stuff myself (with his help which he is very generous with.) He pushed me to do the plumbing and electircal in my cabin, which I did, and I'm glad. But the one (and only) thing I did hire out on that was the foundation work.

So we'll see.

[MrJimi]

I've done paint and body work all my life and I look at concrete like 9 yards of body filler that WILL harden fast, be careful, it don't grind smooth easy
do your self a favor and hire some professionals to do it and watch them