Concrete Questions

[LD1]

Dargo- Did you use anything under the concrete for a base like limestone. If not I agree that the concrete needs to be thicker than normal if pouring over dirt.

Everyone is entitled to there own opinion, and I respect everyones, so I am not trying to start a war.

For what you are doing, IMO I think that 4 inches with wire and fiber will be pleanty if you use a good 4 inch limestone base. I think rebar will be more hassle than you want and i don't think you need it.

Just as an example, the factory where I work has 7-8 inch concrete w/rebar and it routienly has 25,000 lift trucks drive over it, 35,000 lbs whn loaded. And these trucks have a shorter and narrower wheelbase than a car so the load isn't being spread out. Concrete has stood up just fine for the 15-20 years it has been down.

I will be pouring my garage in the summer-fall where I will park my truck, and it will be 4" cocrete over 4" limestone with wire and fiber.

And like others have mentioned, its hard work. Be ready to sweat. And the more helper you get the better it will be.

[ampsucker]

i'll add my .02.

i'll never put down another slab without some type of footers. at least where we live, it is guaranteed to move if you don't get below the frost line. i have come to think of a concrete slab as a giant piece of very heavy styrofoam floating in a sea of very thick water (dirt). when the spring rains come, if the load isn't exactly even (like a heavy tractor parked on one end and nothing on the other or a heavy brick chimney if it's a house, etc.) that baby is going to sink into the muddy, loose, frost heaved dirt. granted it's not that big of a deal on a slab for a pole barn, but you get the idea. why not do it right the first time?

second thing i've noticed about slabs and pole barn. at some point, you always fantasize about closing them in. maybe you get tired of snow blowing in all over you equipment. maybe you need a place to cover you plants. maybe you hate all the leaves that blow into it and get stuck around your implements in the fall. maybe the packrats start eating your wiring. whatever. maybe you want to tie into later with a breezeway and you don't want the thing sinking and warping on you. plan for it now. if you skimp on the slab, it might not support what you want to do later.

expansion joints anyone? i like to see one every 10-12 feet or so. more if thinner.

drain pipe and gutters. know where your rain water is going to go? ever want to powerwash your equipment in the shade? a little planning and 100 bux in pvc pipe now and these won't be problems for you later. nothing erodes under a concrete slab faster than a good running downspout with nowhere else to go.

amp

[Dargo]

Originally Posted by LD1

Dargo- Did you use anything under the concrete for a base like limestone. If not I agree that the concrete needs to be thicker than normal if pouring over dirt.

Here's a picture today in the rain. As you can see we're using #11's and compacting them. Some of the pumper trucks and concrete trucks coming down my driveway are approaching 90,000 pounds. Literally dozens and dozens have been up and down with no problems. And, I do have forklifts running in both of my barns. They do put down quite a bit of weight in a small area. However, one real plus of the added strength was demonstrated in the last few weeks when we had several earthquakes. The good base and strong well engineered slabs survived well.

To be honest, I did get talked into using the fiber reinforced concrete around my pool area. No offense, but I wish I hadn't. I'm not impressed with it at all. I have more cracking with it than any other concrete I've had poured anywhere. Like I mentioned earlier, this will make nearly 800 yards at my place. Since it's sooo darn expensive to do (at least in my book), I'd rather take my lumps up front with the cost than having to tear it out like I did the first section that was only 4" thick. There again, I plan to live here all my life and I'm doing this for the long run as well.

I also included a picture of the pumper truck which made it far easier to reach all the way inside the barn.

[Dargo]

Originally Posted by ampsucker

drain pipe and gutters. know where your rain water is going to go? ever want to powerwash your equipment in the shade? a little planning and 100 bux in pvc pipe now and these won't be problems for you later. nothing erodes under a concrete slab faster than a good running downspout with nowhere else to go.

amp

I've always found that it's easier to put drain pipes in before I pour concrete as well. All of my barns have floor drains built in as well has having 2' deep footers around the exterior edge with 2" Styrofoam insulation as a form on the outside edge underground. I've never had a problem with frost heave. And, yes, some people think it's only important to have downspout drains if you have a basement. I'm surprised to see how many barns are around my area with no gutters at all and have lines drilled into the ground from where the water has eaten into the ground. Again, to me, it's cheaper in the long run to just bite the bullet and do it right to start.

[PA hayseed]

I really don't know much about concrete like these other posters, but,

I would definetly check into the concrete being dyed or the white concrete. The other type is grey. My main reason for saying this is unless you are planing on sealing/staining/epoxy your floor there, the dye/stain added to the concrete will reflect the light and make the inside brighter.

having had floors in garages both ways, I found I prefer the whiter variety for light reflection. It doesn't really cost much.

I also second the drains, wouldn't have a slab anywhere without them, just remember to put a cleanout in too. And don't forget to stub your power or water lines if your installing that below grade too.

[N80]

Originally Posted by jonbravado

I am about to start my project like this in a couple of months - i am using telephone poles for the posts, metal roof, and will be using gravel or 'slag' for the floor - i was pricing kits and concrete and decide to make my tractor shed on the cheap, but it will be plenty big and plenty dry when i'm done.

These good folks have convinced me to do the same thing!

My original thought was that I'd frame the area up, pour the concrete, screed it out as best I could and let it dry. If it was lumpy, unlevel, etc, it wouldn't make that much difference. But, it seems a bit more complicated than I naively thought and I don't want to make a $900 mess.

So I think I'm going to order a truck load of crusher run instead. Maybe throw some rubber stall mats down if I need to.

Thanks guys.

[Wesdor]

I'll add my comments to hire it done.

I build a 36 x 64 shed last spring and hired the cement work. We put in 6" of crushed limestone rock which was rolled and then 6" of concrete with fiber in it.

They brought a crew in the morning and by evening it was curing. We sprayed water on it for several days and then put concrete sealer on it before putting it to use. Turned out very nice and I'm happy I had someone else do it.

[EddieWalker]

With your requirements, gravel and mats will work as well as anything. I think that's a great idea.

Eddie

[sandman2234]

I worked in a prestress yard in my younger days, then moved into Q.C. when I figured out an a/c office was better than being out in the sun all the time. Plus we could still work when it rained.
My take on the rebar/wire/glass reinforced concrete is simple. The people selling the concrete make extra money by adding the fiberglas reinforcement, so they are pro glas. I have tested it cylinders with and without, and it doesn't make as much difference as they seem to claim. The square mess does end up on the bottom, even with chairs, because the laborers are walking on it during the pour. That isn't good, and hard to do anything about it. Rebar, about a #4 spaced evenly across the entire slab will work wonders but even that won't do anything if you exceed the limits of the concrete. If I were pouring it, and it wasn't much more, I would add all three, as they all have their good points. However, since money doesn't grow on trees, I would do the rebar, and put in way more of it than you ever think your going to need. The mesh is required here, so I would have to use it, and would put rebar in on my own.
My Pastor just tore up his bathroom tile, because it was cracked.(Ceramic)
The reason became clear after the removal of the tile. The slab had cracked and he told me they did the glas reinforcement, no other reinforcement with it. Builder wouldn't stand behind it, so I suggested finding a good epoxy to fix the crack with before putting the tile back in.
If you decide to get back on this project, good luck with it!
David from jax

[Slackdaddy]

Been in concrete for 20 odd years,
The rolled wire is useless, it is to wavey, some is on the rock, some is poking through the top.
I use 5' x 10' wire mats, the heavy gauge (2 or 4, I forget) it is very thick and has "rebar texture" to it, it is like mats of "mini rebar".
I use 2" rebar chairs to hold it off the bottom.
Never "pour" a slab, Place the concrete, on about a 3 slump and use a vibrator. I allways shake My head when I see a crew wetting it up and pouring it, Your 3000 PSI crete is now about 1500, and the surface WILL pop and spall in a few years.
And allways keep a fresh slab wet for 14 days.

Slack