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DRH1175

Pouring a driveway?

37 posts in this topic

I am pouring a 28x24 driveway 4" thick is this thick enough and do I need rebar or Wire mesh. I am putting in 6" of class5 of base over sand. Also has anyong put down pink foam under the slab How does that work?

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I'd forget the class 5 it heaves and retains moisture cause of the clay in it,Just a sand base and 6x6 mesh maybe a #4 bar by drive apron.

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Use a sand base and compact the sand. 2x4 forms and #4 rebar 2'x2' squares is the way I do it.

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Sand is the worst base you can use for concrete. It doesn't pack at all. All of the jobs I have seen specs for have required class 5 for a base. These are both commercial and residential jobs. I would give a taillight guarantee if my customer wanted a sand base. As for the wire mesh, if you can be sure to pull it up as you pour, it works. Unfortunately, most people put it down, run the wheelbarrow over it, give it a little tug once in ahwile, and it ends up on the bottom. If you are worried about your driveway, add rerod with stairs to hold it up.

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Your right walleyeseeker sand with a binder like a little clay. Not really class 5 though. also I would pin it to the other concrete by drilling it with a hammer drill. I would use rebar instead of wire mesh you will get a stronger slab and won't crack as bad as wire mesh. But it also is how you finish it for surface cracking.

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if the class 5 is down already leave it it will be fine. as far as drilling and pinning to other concrete only the sidewalk. do not drill in to the curb and pin to it. as far as reenforcement order some fibermesh or micro fiber in the load and then add some 1/2 inch rebar at the bottom and the top by the garage and this should be more than enough. if you are parking or driving anything heavy on it bump that part to 5.5 inch with some extra rerod and you will be fine.

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fish2live makes a good point. With a 3.5" slab and fiber cement it makes no sense IMO to even mess with wire or rebar. Anything big enough to crack that, then you should be bumping up to a thicker slab. We are talking dump trucks and such for heavy weight(20K plus lbs).

Sand packs great if you dig out all the top soil and maybe another couple feet of [PoorWordUsage] soil, then put in sand...water it good, pack it good, and it is hard as cement before you pour.

Alot of it does have to do with the finishing also, along with the weather at the time.

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Also, the reason for sand is that it doesn't hold water long, so then it won't freeze and heave in the spring.

I'm no cementhead, but this is what I have seen on our jobs we have done. There are some guys here that do cement. Maybe they will give their opinions also.

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All I know about the sand Vs class 5 is that at the airport (MSP) under the new runway and deicing pad it's class 5. I figure if there was anything you don't want moving and heaving I'd say it's a runway. If it where mine I'd use class 5 packed with a vibrating plate (not a wacker) and use #4 rebar and 5.5 inches of concrete. The price difference isn't enough to really make a difference. Will you ever compalain if your driveway is to strong or to weak?

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If you pour it 5.5 is a wast of money and concrete. 3.5 is just fine I've done a few driveways for quite a few customers. #4 rebar, pined it to apron but not curb 2'x2', placed concrete and cut control joint in. You can pour it thicker if you plan to run a highway on it with heavy tucks.

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I've done concrete work for 10 years and our company has never tore out a driveway yet. We use fill sand to bring the grade up to 3.5". Tamp the fill sand good. We use fibers in the concrete instead of rebar. Do not pour the concrete wet. The wetter the concrete the less stronger it is. This also causes the slab to peel. As previously said 5.5" is way to thick unless you plan to park something heavy on it.

As far as the foam underneath. We have done 1 job with this with a patio in Lutsen, MN. It acts as a another layer for the frost to get around. I am going to use it on my sidewalk this fall. Most people don't get it because of the cost of the foam.

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Biff does that foam really do much? It seems the cold will penetrate any insulation without a means of warmth??

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Four inches is adequate unless you plan on really bringing something really really heavy in on a routine basis. Regarding rebar vs fiber reinforced concrete, spend the few extra dollars and put in the rebar. If you really want it to last, go with the rebar at 2 ft intervals. The problem with fiber crete is the way some ready mix companies add the fiber. Very often it doesnt get adequately mixed to really perform as designed.

And remember, there are two kinds of concrete: That which is cracked and that which is about to crack smirk

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Again, what's "heavy"? Is a 5000 pound pickup parked 12 inches from the edge "heavy"? A 3000 pound single axle trailer parked in the same spot? How about a 8000 pound service truck parked in the same spot? The point I'm trying to make here is what's heavy to you might not be heavy to the next guy and vise-versa. Let's qualify things and put some weight ratings on here so we can talk apples to apples.

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MNFishingGuy, you are right about being more specific regarding weights. I guess I was thinking about a "typical" home application that might need to support things as you mentioned. The real problem in being specific is there are a lot of things that come into play in terms of really being able to specif what a slab can really carry. Probably the two most impoirtant factors are: type/strength of the concrete used and compaction of the soil underneath the slab. Really, without knowing that its hard to give much of an estimate of what the slab could really carry. For your examples though, a 3000 psi concrete with a well compacted soil under the slab could easily carry the loads you have mentioned.

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The question asked is about a 24x28 driveway (not real big). Do you really think he brings home a dump truck and park it on a 28 ft driveway? Probably not. I have had my Rv (over 12,000 lbs) on 3.5" fiber and had no problems. I have had our 16K lb. lift on 3.5" driveways and nothing happens. Like I already stated, if you get over 20,000 lbs daily on it, I would upgrade to 5-6 inches with rebar. Other than that, it's a waste, IMO.

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Roofer, your probably correct. Now for the cost difference of adding an inch, what would you do? It sure does cost alot more to be an inch short than an inch long. A guy never knows what the future is going to hold or what your going to drive.

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I have done concrete for 12 years and we always put class 5 down. We pour on average 100 yards a day, (Highway Heavy). I would go 5 inches of concrete, rebar and fiber mesh. It's going to cost you a little more money, but it will last a long long time. You will not be happy pouring the drive at 3 inches thick.

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The difference to the average person is nothing mnfishinguy. The difference will be how much it costs, and that seems to be number 1 on everyones list right now.

If you are doing commercial stuff, money isn't as big of an issue and alot of times it's overkill on the projects.

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You can go cheap the first time around but you will pay for it later! Do it right or don't do it at all!

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I have done concrete for 12 years and we always put class 5 down. We pour on average 100 yards a day, (Highway Heavy). I would go 5 inches of concrete, rebar and fiber mesh. It's going to cost you a little more money, but it will last a long long time. You will not be happy pouring the drive at 3 inches thick.
Thats goin overboard! And have you noticed how great and longlasting our HWYs are?

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How great our highways are?? What are you talking about?? We are talking about a driveway? Not sure what you mean here?

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Since every idea in the book has been thrown out grin, I will just state what I would do if it where my drive way.

I would not remove any earth from the area to bring in added soils or aggregate, unless the ground is pure reclaim or recycled material (I.E. not virgin soil). If it is pure clay, what is 6" of class5 going to do for ya, except cost you extra money and sink/absorb in the clay.

Dig it out and level out with earth removed in the pour area. If none is to be had from the site, I would bring in regular clean fill, level and use a hose to settle the filled in areas. You can bring a tamper in if you want, but when talking about a couple inches, watering with a garden hose will suffice. Form up with 2"x4" and tie into any and all concrete connected to the slab. I would use rebar and go 2'x2' on center (4'x4' is just fine, but this would be my slab). Do your level markers for the screed if you want. I also like to put rocks and concrete chunks under the rebar mesh to help hold it up off of the ground, but pulling up during the pour works just fine. Pour the concrete, screed, get out the boards and mag, bull float, do your tool cuts unless you plan to saw cut the next day (I like to have my cut points marked on the form boards before the pour. I try to equal the surface are out, but have done 6’x6’,8’x8’,10’x10’,12’x12’ cuts), finish the edges, have a beer or two and then brush finish.

Remember to tap the form boards with a hammer right after that area is filled with concrete to relieve air pockets on the side of the slab to prevent side bursts.

Fiber added into the mix is not a bad idea. The cost has leveled off and if anything, it does give peace of mind. The best thing to do when ordering the concrete is talk to the place you are ordering it from. They will know the correct mix to use in your area and with what you are doing.

Good luck and I am a form believer in pour in the AM and seal in the PM on the same day. The slab is the cleanest at this point and it gets it done!

This is just a very general over view of what I would do. If a customer wants something out of the ordinary, I would do anything for a price. Customer is always right, even when he is wrong wink.

Believe me, some people have their minds set on something, they will not change and pay extra!

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