How thick should the concrete be?

[#90-GTSC]

I'm going to build a new race shop at the end of the existing concrete drive. The apron between the shop and the existing drive will probably be 10 to 12 feet. Between the shop and the lot line (25 feet) I'm going to pour a pad to park the enclosed trailer (now 24') and the tow vehicle.

The existing two vehicle is a half ton Suburban. The plan is to replace it with a 379 Peterbilt with a 28 to 30 foot box, bumper pull, and tandem or single axles. All depends on what the down on his luck seller has to sell. Or maybe a Prevost (especially if I can steal one!)

How thick should I pour the pad and approach from the existing drive? 4"? 5"? or 6"? I don't want to necessarily over build, I'm a little on the cheap side, but I will pay to do things right and not cut the wrong corners.

What have you guys done? What works? And what hasn't worked too well.

[Bob86ZZ4]

Dick, can you get a concrete guy to come over and give you a free estimate? That way you can pick his brains about what thickness and such? I know less than nothing about concrete. I have a friend that is a concrete engineer. His company builds parking ramps and lots so he knows all about concrete. I'll run your question by him if I get a chance. But, I would think there would be a contractor in your area that would bid on the job.

[mmmc101]

Dick, I would pour it 5 inches if you plan on a 379 Pete. The truck will have 10-12K on the steering axle and that is on a small footprint. I also would use 1/2 inch rebar on 2ft centers with 3500 psi concrete. I have built 6 commercial steel buildings in the last two years and have not had any problems with the driveways or floors. Most were for commercial trucks or large motorhomes. My cost for material (3500 psi concrete, steel,sand) runs about $2.50 per square foot for a 5 inch floor/driveway. Anything above that is labor.

[Bob E]

I just finished pouring the floor for my Conversion parking canope. We excavated 12" of dirt & clay, layed a crushed rock base (a couple of inches) then put in 4" of sand. We then layed in 1/2" re-bar on a 24" grid and poured 6" to 7" of 4000 test concrete with fiber added. I've let it cure for 4 weeks & will move the conversion back in tomorrow. I did some of the forms & re-bar work myself so saved a little on labor. The #4000 concrete was $95/cu yard (poured 27 yards), a load of sand was $100, I already had the rock. The labor to do the excavtion, pour & finish the concrete etc, was $1600.
When you do any concrete work, spend what it takes to lay down a good base and don't cheap-out on the re-bar. (do not even think about using that wire mesh crap, it's worthless).

[andyg]

mmmc is probably about right @ 5". It depends a lot on the type of soil that will be under it. Your concrete will not be much better than the base it is poured on. Use 3500-4000# with fiver for the "easiest" job.