Posted: 4/23/2014 6:35:03 AM EDT
I've gotta pour a 2x3' section to extend my front porch, a 14'x1' section under my gate, and a 11x11' pad for a shed. I may also need to build a short wall, no taller than 2.5' and 8-10" deep and maybe 4' long. On hand I've got a couple wheel barrows, a couple shovels, endless lengths of 2x4's and 2x16's, a couple hundred feet of 5/8" rebar and tools to cut it, and that's about it. Is it generally a good idea to rebar-reinforce everything, and how deep is generally accepted when pouring? I wouldn't mind overbuilding if it would save me some trouble in the long run. What concrete types do I use? Is Quickcrete worth the extra $10 per bag? How likely am I to totally mess up pouring it on my first try? 
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| we pour concrete driveways to a minimum depth of 6 inches, patios and walkways 4 inches, over a compacted bed of crushed gravel, reinforced with wire mesh. I've never used rebar for a driveway or patio job, only wire mesh. Follow the mixing instructions on the bag. Too much water will weaken the strength of the finished concrete. |
| Looks like you got enough to take a couple of yards just order it from the concrete plant and stay away from the quick Crete especially since you are pour some big flat areas. If you have never pour big pads before I suggest you hire it out to someone who knows what they are doing or you will regret it. |
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Finishing will have the biggest learning curve. You can learn a lot more by watching a 5 minute YouTube video than I could ever hope to explain here. Get an idea of the tools used, THE TIMING OF WHEN TO USE THEM, and remember....less is more when it comes to finishing. Your finishing time will vary a lot based on environmental factors, concrete mix, admixtures, etc. There is an art to it.
I can't get into any specific comments on rebar without knowing more about your situation, but #4 bar at 12" each way throughout your slabs will get you pretty darn close to an often prescribed welded wire fabric used for driveways and sidewalks.  When setting bar for a slab, ideally you want it about 1/3 up from the bottom, with minimum coverage of 1.5" on all sides (for a 4" slab, the middle is just fine). Home Depot, Lowes, and of course any concrete supply house will sell chairs sized to keep your bar or mesh at the appropriate height.
Using 2x dimensional lumber is just fine for forms. Remember to rip the boards, especially on the top side, to get rid of the radius, otherwise that will be reflected in your concrete. Use form release oil so they come of easily...and make sure your forms are rock soild and nice and tight. If you can't get form release oil, other oils will work in a pinch, but will effect the color of your concrete. While you are ripping boards, rip a nice straight 2x6 to use as your screed board. Go back and rewatch some YouTube videos if you don't know what that is. Before pouring (and forming), make sure to strip out all the topsoil (first couple inches) and use a suitable base material. Around here, well-graded crushed limestone is common (and preferred). In other areas it may be bank run gravel. Lay down a suitable base and compact it. Bag mix is fine, though a pain in the ass. Assuming your shed pad is 6" think (just an assumption, not a recommendation), you have about 2.25 CY of concrete. That's about 100 80lb bags of concrete. You won't ever get a decent product like that if you are working alone....even with a mixer. Stay away from any of the fast setting concrete....you'll need all the time you can get to finish it. I'd do a couple smaller slabs via bag mix first, get some experience finishing it, and then get a truck in there to pour the rest. Keep in mind that 3CY is usually the minimum you can order. You will want a footer for your wall. Is it just a wall or will it be retaining anything? Your formwork here will be critical. You will also need some means of consolidating the concrete. I'd just bite the bullet and rent a concrete vibrator from Home Depot for $30 a day. It will be especially critical for the wall otherwise you'll have honeycombing out the wazoo. You can use a length of rebar to rod the concrete....but vibrating is easier and better....and time isn't on your side when you're pouring concrete. If you are butting up against existing concrete, I would throw in an expansion joint. Without seeing it, I cannot comment further, but it won't hurt. Consider cutting some control joint in your long slender slabs to avoid uncontrolled cracking. This is all just off the top of my head and is in no way a comprehensive list. |
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I think you've gotten good advice.
+1 on the professional job if you aren't able to "practice" and it's a very visible spot where the wife will complain if it's not perfect...
If you order off the truck (which you probably should) then you'll most likely need to meet a minimum, since you're just a one-and-done kind of customer. This will let you do a thicker slab if you want. If any of the areas will see vehicle traffic, make it at least 6" with some reinforcement. 4" is fine for pedestrian traffic. I remember pricing a commercial job where the drafter must have mixed things up and they spec'd some of the sidewalks at 8" w/ rebar and the dumpster pad was only 4" 
Don't forget to tool or cut joints on any long stretches, like that part under your gate. If you cut them, that will be easiest because it will give you one less thing to worry about during the toughest timing of the finishing. On the other hand, you may need to rent a saw for that and you don't have much cutting at all to do. Plan where you want your joints so it looks like it blends in if it's against an existing driveway or whatnot. |
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Thanks for the advice!
I did some calling around, I can buy 1cy of ready-to-pour concrete, already in a mixer and on a trailer, for about $150. I think I am going to go this route; if anything, it'll greatly reduce the ways I can fk up the whole project.  They claim it's enough concrete to do 80sqft @ 4" depth. I'll probably do 4" depth on the patio extension and 6" on the fence and still have some left over.
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Quoted:
Thanks for the advice! I did some calling around, I can buy 1cy of ready-to-pour concrete, already in a mixer and on a trailer, for about $150. I think I am going to go this route; if anything, it'll greatly reduce the ways I can fk up the whole project. They claim it's enough concrete to do 80sqft @ 4" depth. I'll probably do 4" depth on the patio extension and 6" on the fence and still have some left over.
Remember you have to get rid of the "left over." |
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Quoted:
Remember you have to get rid of the "left over." Quoted:
Quoted:
Thanks for the advice! I did some calling around, I can buy 1cy of ready-to-pour concrete, already in a mixer and on a trailer, for about $150. I think I am going to go this route; if anything, it'll greatly reduce the ways I can fk up the whole project. They claim it's enough concrete to do 80sqft @ 4" depth. I'll probably do 4" depth on the patio extension and 6" on the fence and still have some left over.
Remember you have to get rid of the "left over." ...and carefully consider your travel time from the mix plant and how long it will take to distribute it in your forms. I did the haul it yourself in a trailer one time... I was cramped for time and the finish suffered. The hotter it is, the shorter time you have. The little mix plants that do haul-it-yourself are not usually the best with additives to slow/speed/freeze protect. Buy a big sheet of plastic and have it ready for clean out. Dump and wash out onto the plastic. Chop the concrete up with a shovel just as it starts to harden to keep in pieces small enoght to handle after it dries. I your doing a yard, have a at least a couple of people to help PLUS someone to clean out and return the trailer back. |
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Quoted:
Remember you have to get rid of the "left over." Quoted:
Quoted:
Thanks for the advice! I did some calling around, I can buy 1cy of ready-to-pour concrete, already in a mixer and on a trailer, for about $150. I think I am going to go this route; if anything, it'll greatly reduce the ways I can fk up the whole project. They claim it's enough concrete to do 80sqft @ 4" depth. I'll probably do 4" depth on the patio extension and 6" on the fence and still have some left over.
Remember you have to get rid of the "left over." OP your 11x11 shed pad is going to use 1 1/2 yards at 4 inch thick If I were you I would do it all at once and have it delivered on a truck then they will haul away any extra. Call the plant and give them all your measurements and let them figure the total yardage and then add a 1/2 yard to the order. Nothing sucks worst than coming up short and only needing a wheel barrel or two extra. |