Can you estimate the cost of a concrete pad?

[Tractor Seabee]

I am trying to plan for adding a concrete pad to my driveway for extra parking and my sons basketball goal.. Is there a way I can estimate the cost myself so I am prepared when I do call for estimates?

Also is there prep work that I can do myself to save some money like digging, framing etc? Are there people that will just come in pour and spread?

Thanks
Wade

Wade,

There are some good things said here but some take with a grain of salt. I have been a member of the American Concrete Institute (they do research and set all the standards for concrete construction) and a concrete inspector. What I will tell you is the subject of many good ole boy rants as nonsense, but it is based on lots of research and testing. The following is only based on an outside driveway application.

All concrete does not crack. There are many variables that can cause it to crack but most can be controlled.

Question: what type of soil do you have? Answers: If it is sandy/rocky you will not need any gravel under it. Be sure to strip off all top soil first, then grade relatively smooth the thickness you want the slab. If you are building on something other than sandy/rocky soil strip out another 3-4" for the gravel subgrade you have to put under the slab. Use 3/4" minus crushed gravel, rake it out even and tamp it down with a plate compactor or a hand tamper (up to you which).

Build your form from 2 X 4s using double head nails. Splice all joints with short pieces. Line it up with existing and square it up on the end. drive a stake every 4 feet. Metal stakes; drive below the top of form, wood stakes; you can cut flush after setting height. Start at ajoining slabs and set form flush with the top and nail with one nail at each location. At each other corner nail to the stake at the grade you want to make it. If you are a little high thats OK and scrape down if you need to lower it some. Set a string line at the top to make sure you nail to each stake and keep the top in lone. After it is all nailed and graded put the second nail in each stake.

Check the grade of the subgrade to make sure it is at least 3.5" or more every where and then water down good with a sprinkler.

Find that guy that will place the concrete, screed it, float it and broom it. If you want a gravel finish he will take care of that also. You do not want to tackle this unless you are a pro and have the proper equipment.

Forget about wire mesh, rebar, and mesh hooks. Think about the physics involved, try to stand on that wire mesh and hook it and pull up on it. I defy you to budge it. So, that is a waste of money. Wire mesh is of no value if it is not in the right place in concrete. Buy heavily fibered concrete mix and you will be fine.

Work with your finisher and order the concrete, 4000# fibered 3/4' aggregate or pea gravel if that is the finish you want. Depending on local conditions he will know if any other additives are needed. When the concrete gets there stand back and let him do it. Warning! discuss this before hand; do not add water, get the mix right for the conditions.

He will consolidate, screed and bull float. Discuss this before hand also, he will cut in the control joints as soon as he can get on it. His cutting trowel needs to be at least 1.5 " deep. Match spacing of existing and if more than 14' any direction cut it in half.

Now! its is all up to you, depending on weather, keep it wet and shaded from the sun for several days.

Lots of luck, and no cracks. If your finisher wont agree to the above procedures, find a new one.

Ron

 

[clovergamecock]

WOW!!!! Thanks for the detailed write up Ron!! This is extremly helpful. I definately was not planning on pouring and smoothing it myself. I was just thinking about doing the digging and framing myself and then step aside and let the pro do his job.

I live in SC. The soil around my house and in the spot of the planned pad isn't sandy or rocky. It use to be a cow pasture. The first few inches are fairly lose but then the soil get really hard. So I am assuming that from your write up I would need to dig down 8" roughly???

I take it from your screen name you are NAVY. Thanks for the info and advice shipmate!

OS2 :thumbsup:

 

[flusher]

I am trying to plan for adding a concrete pad to my driveway for extra parking and my sons basketball goal.. Is there a way I can estimate the cost myself so I am prepared when I do call for estimates?

Also is there prep work that I can do myself to save some money like digging, framing etc? Are there people that will just come in pour and spread?

Thanks
Wade

Determine the type of concrete you need (3000 psi, 4000 psi, etc). Measure the volume of concrete in cubic yards and multiply by the local price (usually ~$100/cy). Determine the amount and size of rebar you'll need and get a price estimate by a visit to Home Depot or Lowes and reading the price tags.
Determine the amount of crushed rock you'll need and call around for prices.
Add in the cost of plastic vapor barrier. Then figure the cost of lumber for framing.

When I built the footings for my new carport (20x36 ft), I did the spade work and the framing. Ordered ready mix concrete (6 cubic yards) and my neighbor and I did the pour.

Good luck.

 

[Fixemall]

Ron has it right, all concrete does not crack. Base and drainage is key! My pad outside my garage is 24'x30 and has been down for three years without a hint of cracking, I should also mention the area was raised over six feet to meet grade and regularly has four cars and loaded trailers on it. I used broken pavement topped with slag, topped with millings and crushed it all in with a large excavator, topped it with limestone and waited a winter then poured it using one of those semi trailer concrete trucks.

 

[namesray]

i just did a 20.5' x 20.5' pad on friday for 20x20 enclosed carport shed. me and a friend build the forms using 2x6 boards (5" thick pad) and used steel spikes (3 ft long) to anchor and help brace the forms. price of the concrete was $115/yard plus fuel charge and fiber charge and calcium charge (to help cure faster here in the cold north). price of just the concrete pad (7 yards) was $945.65. plus the 2x6 boards to frame it in, plus the drain i put in, plus the plastic we put down under the concrete. plus what i paid my friend to help (he has done concrete before). close to a $1500 dollar investment. and that doesn't count the 4"+ washed 2b gravel underneath for under drainage. had just enough left over to do an apron for entrance and small step pad for man door. went smooth, but i don't look forward to doing concrete ever again. hard on my back screeting and finish work. kinda all simple if you think about it and get all the steps right, but a lot can go wrong if you forget something. concrete will not "wait" for you to "get it right". once it sets up its there. it can be done by the do it yourselfer if you get everything done and lined up properly. i wouldn't attempt it with out help from a friend or a couple of them. being your first time, and a pad as big as a basketball area, i would think about having a crew come do it. or atleast have someone with experience be there to help you. i helped do concrete jobs way in the past before, but if it weren't for my friend this time, there would have been small things i would have forgot or not had quite right that would have been disastorious on pour day. good luck and let us know how you make out.

 

[Gary Fowler]

One thing I havent seen mentioned which is a good idea if the slab will see some heavy traffic is increasing the thickness to about 6" minimum on the perimeter for at least 12" distance. This will provide additional strength to avoid cracking off of corners which is a common enough issue with driveway slabs.

 

[Diamondpilot]

In my area its about $.65 per sq ft to pour and finish it. If you have them do it from start to finish all inclusive its about $6 per sq ft.

4000 psi concrete is about $100 per yard.

I had a 40x15 slab done 3 years ago and I dug it out myself using a neighbors Case Back Hoe and Ford F700 dump truck. It was 10 yards of concrete @ $1000. Fuel for the equipment and 6 cases of beer as a good will gesture @ $150. Wood for the forms and wire mesh plus 12 tons of gravel @ $350.

All in all it was $1500 for materials and $400 to have it poured and finished.

If I had not done the two full days of prep work it would have been about $3500. Yes, I saved some money but it was 2 hard days of work.

Chris

 

[Tractor Seabee]

WOW!!!! Thanks for the detailed write up Ron!! This is extremly helpful. I definately was not planning on pouring and smoothing it myself. I was just thinking about doing the digging and framing myself and then step aside and let the pro do his job.

I live in SC. The soil around my house and in the spot of the planned pad isn't sandy or rocky. It use to be a cow pasture. The first few inches are fairly lose but then the soil get really hard. So I am assuming that from your write up I would need to dig down 8" roughly???

I take it from your screen name you are NAVY. Thanks for the info and advice shipmate!

OS2 :thumbsup:

OS2, (are you still ACDU?)

Didn't mention in the post; I am also a retired Seabee so have seen a lot of concrete work. Retired as a CWO4, former UTC. I have worked in and around construction, military facilities (PW) and contracting for 60+ years.

Un-controlled Cracks and failures occur when the procedures are shortcut or control joints and/or curing is done sloppily. Plenty of the old time finishers will poo poo my rant, also they are the ones who will tell you all concrete cracks, guess why!

As mentioned by another poster; if your loading is going to be more than cars or light trucks consider a 5-6" slab with thickened edges. Your existing is probably only 4" though. Keep dimensions between control joints no more than 12-14' both directions, smaller is better. That is where you want it to crack as it shrinks. Yes concrete will crack, you just want to control where. Keep that sun off it. As the days get longer consider the pour late afternoon and finish before sundown, or under lights. There are procedures for hot weather concreting but in your case too expensive to consider. Cloudy misty day is the best under 70 F temp.

Good luck shipmate

 

[Redneck in training]

Last year price in Iowa was $3.50/sqft excluding 16 ton of crushed limestone that I had to buy and had it delivered. I also had to buy moisture and thermal insulation. The concrete is 4" 4000 psi, reinforced with re-bars 16" on center placed on chairs. The contractor installed and compacted the limestone, installed moisture (black plastic) and thermal insulation (pink stuff), re-bars had delivered the concrete, rented a pumper etc.