I have some questions about adding a Concrete Driveway extension

[JohnMcD348]

So, I'm planning for the future. In the next short years, We'll become a 3+ car family and I was going back and forth about the idea of pouring a expansion off my existing driveway or just laying pavers.

I think I've decided more toward concrete so it'll nearly match the existing area.

I'm thinking an 8ftx16ft area will be adequate to park another vehicle on but I may go 20Ft.

I would have rebar for reinforcement.

Max weight I'd ever put on it would be just over 9000lbs. My Truck is the largest vehicle in the family. Nobody has anything bigger.

So my initial questions:

How thick of a slab do I need to pour? 2inch? 4Inch? Is 6inch overkill?

How much rebar would be enough to adequately strengthen the slab?

Is there a standard length/width of slab that divide the total into? ex: 2-8ftx8ft slabs if 16ft long or 4-8ftx5ft slabs if 20ft?

I'm probably going to be doing this with Quikrete instead of ordering from a cement company.

Thanks

 

[Bondo]

Ayuh,.... If ya go with a 4" slab, I'd use mesh, rather than rebar, 'n thicken the outer edges abit,....
At 8'x 20', that's 'bout 2 full pallets of bag mix,....

 

[SARG]

Mixing that amount by hand is insane and will result in a **** job.

 

[12ozd]

I would use wire mesh inside the slab, and ready mix truck outside the slab.

 

[DekeT]

From the quikcrete site you will need 95 of the 60lb bags. Good luck with that!

 

[volleyball]

Plan on ordering up a truck. Depending on how old the driveway is maybe you want to color the new slab to make it stand out like it was on purpose.
I'd rebar the perimeter which i'd make 6" and mesh on the 4" center.

 

[DMaxRocks]

/\ What this guy said!!!

 

[JohnMcD348]

Cool. Thanks for the info. Please keep it coming. In the back of my mind I seriously thought that doing the bagged mix was a bad idea but my wife seems to think that since she's watched her father and brother do it so many times that it wouldn't be a problem.

I'm going to make sure she reads this thread.......

Also, thanks for the recommendation of using mesh instead or with rebar. I really wasn't thinking that the mesh inlay would be strong enough to support the weight and size of the slab.

Question:

Whether using Mesh and/or Rebar, does it need to be positioned so that it will be "inside" the concrete after it's poured or should it just be on the ground to give it something firmer to harden against other than the leveled sand bottom? Say, if I were to pour a 4" slab, would I want the reinforcement to sit 1", 2" above the ground instead?

 

[Chris705]

"Also, thanks for the recommendation of using mesh instead or with rebar. I really wasn't thinking that the mesh inlay would be strong enough to support the weight and size of the slab."

4" slab on a really good, well compacted 6-8" base would be ok....if you're not sure about how good the base is, make sure all the top soil and organic mater is gone, 6" slab if you are unsure how good the soil is under the 6-8" base. The mesh is only there to hold the slab together in the event of cracking. Add one tooled or sawcut to control cracking at mid span of the 16' or 20' length. use cure & seal or once set up a sprinkler to keep moist for 2-3 days....

mesh should be 1" above sand base in a 4" slab.....1-1/2 to 2" in a 6" slab....is the sand firm? I don't know much about using sand as a base material....sorry.

 

[Scott r c]

Bags would probably be more expensive and its not near as good as the stuff that comes off the truck.

 

[DekeT]

Cool. Thanks for the info. Please keep it coming. In the back of my mind I seriously thought that doing the bagged mix was a bad idea but my wife seems to think that since she's watched her father and brother do it so many times that it wouldn't be a problem.

I'm going to make sure she reads this thread.......

Also, thanks for the recommendation of using mesh instead or with rebar. I really wasn't thinking that the mesh inlay would be strong enough to support the weight and size of the slab.

Question:

Whether using Mesh and/or Rebar, does it need to be positioned so that it will be "inside" the concrete after it's poured or should it just be on the ground to give it something firmer to harden against other than the leveled sand bottom? Say, if I were to pour a 4" slab, would I want the reinforcement to sit 1", 2" above the ground instead?

If my wife suggested to me something was easy I would let her take the job. Just saying.

 

[dannyv6]

8x20 is 160 square feet.
At 4" thick it's only 2 yards of concrete. At 6"thick its 3 yards. Either way your paying for a minimum cartage charge.
If it was mine, I would make it 6" thick, with #4 rebar, one foot on center. Wire mesh is good for tomato cages not a concrete driveway. Also when you order the concrete order a 6 bag outside flatwork mix. That's 4000 psi with 4 to 6% air entrainment. The air helps with freeze/thaw conditions. Tool or saw it 1 control joint at the 10 foot mark. Put a coat or 2 of a quality cure and seal from a concrete supply house on. That will help with road salt that drips off the cars in winter. Salt is the enemy of concrete. Wait a week to drive on it after the pour and enjoy.

 

[dannyv6]

Also, you want your rebar to be at the bottom 1/3 of your pour. 6" pour means the rebar should be at 2" from sub grade. That's where you get your strength from rebar. The bottom 1/3rd.

 

[James-W]

If it were me, I would look into the cost of the pavers versus the cost of the concrete. When done correctly, pavers look VERY nice. Not saying concrete doesn't look good, just saying pavers can look really nice and if the cost is reasonable for them, you may want to re-think the concrete idea.

 

[FullRaceMerc]

Cool. Thanks for the info. Please keep it coming. In the back of my mind I seriously thought that doing the bagged mix was a bad idea but my wife seems to think that since she's watched her father and brother do it so many times that it wouldn't be a problem.

I'm going to make sure she reads this thread.......

Do a small project before you take this one on. Water heater slab, a small step, anything requiring just a little concrete. Buy the bags & enlist her help by mixing it a couple of bags at a time in the wheelbarrow. Then talk about doing that 50 more times for the driveway. That should help clarify the advantages of calling the truck.

 

[JohnMcD348]

I convinced her last night that, if we go with concrete, it'll have to be from a truck. After figuring how many 60lb or 80lb bags and trying to mix that many before the others began to set. She saw the errors of her thinking.

Since I'm in Florida, with the heat we have here, are there any considerations I need to take for curing?

 

[volleyball]

Things like wetting down the base before you pour. Have heavy plastic sheeting to put over the top once it sets up. And keep wetting it down for a week.