Compaction of the base beneath the concrete is important as well. 6" with wire mesh is a standard in most areas, but it all depends on your soils type. In some areas, it needs to be dug down deeper than 6" in order to bring in a crushed base material that meets the proper compaction requirements before the concrete is poured. This is mostly in areas where it is sand based native soils or areas of extreme wet conditions. If you dont know about your local conditions, you might get a consult from a soils engineer that knows your area and can advise.

You definitely should have steel mesh (or cross tied steel rebars) in (not below) the new driveway slab. Concrete is very strong in compression but not so strong when subjected to decompression (stretching) or shear (sideways) loads. That's where the steel comes into play by strengthening and stabilizing the concrete thereby making it more crack resistant. You don't say where you live, but if it's a cold weather climate a 6" slab is probably a good idea. In a climate without cold winters (i.e. freezing and thawing) 4" is probably adequate although the extra thickness never hurts, just adds some cost.

Typically the mesh should be supported off of compacted soil before the pour midway to 2/3 down from the surface of the concrete. Out here it is common practice to "lift" the mesh up as they pour. I dont subscribe to that method as there is too great a chance of not pulling it up far enough, or pulling it too close to the surface interferring with the finish. The newer fiber re-inforced concrete is often used in patios, porches, sidewalks without the use of wire mesh but it does not finish well and would not recommend it for a drive way/garage. I would personally never pour out a driveway less than 6" in any area.

Thanks for the advice. I'm in Oklahoma, and we get some very cold spells, with ice storms.

The cost is the same for 6", this is what the contractor does around here. He said he never does 3".

These are the meausurements of my driveway:

17' x 36' with 3/8" rebar.

Sidewalk: 4' x 22'.

One expansion in the middle.

The contractor did not add the 6" to the quote, so I need to have him put that since his "verbal" quote was about doing 6" deep. His price is $2,875.

Does this sound okay? This was my first quote, and the only reason I asked him was because he is working in my street on the neighbour's yard.

The old driveway is done in parts, but this guy is saying he will do it with two parts starting at the top of the garage to the bottom near the street. What is best?

That's around $4.10/sq.ft. It's typically over $5.00 sq.ft. out here for drive/sidewalks, flat pours in general.

Always a good idea to start at the house and work towards the street whenever possible.

I am getting another quote tomorrow, and am not as concerned with the price as I am with the company doing a good job. What I find puzzling is why the contractor said he would do it in two parts (length) rather than the six squares I have now. I don't know how to explain this. The old one we have now has grass and weed growing up between the joints, and he is saying that having just two joints would be better.

Sounds like your original driveway had issues with compaction (as mentioned). What is the proposed spacing for the rebar? Also, I would prefer control joints every 7 or 8 feet. IMHO one control joint in 36' is not nearly enough.

I got an interesting contractor today. He said that my driveway is stable, and the only area that I thought was sinking is not really sinking. He said that I can repair it by having all the 1" pieces of wood and weeds removed, then he would blow whatever out of there, clean it properly and install backer rod and use Sikaflex. These are the joints where the pieces of wood filler that was used have come out. The cracks he said were superficial, and unless I had money to blow and wanted a brand new driveway, he felt like it would last another 5 years at least.

Now I don't know what to think. I'm shocked that a contractor wouldn't try to have me go for a new one!

I'm shocked that a contractor wouldn't try to have me go for a new one!

There are still a few honest people left in the world. Of course, in five years who are you going to call? In the intervening time, who will you recommend to your friends?

In northern Illinois, we use a 6-8" base of a grade C8 for a base, compacted (pea gravel is not acceptable). The concrete is a min 5-7" depending on if fiber or 4x4 mesh is used or nothing. Remember 4x4 wire mesh is only good if its hooked into the middle of the concrete.

What the ground excepts it rejects, with that said, the base will make the most difference re: sinking. The strangth of the concrete has a lot of veriables ie ash content, air ratio, etc.