Cement Cost

I would do a 4" slab and if you can swing it throw in some mesh unless you plan on busting it out down the road. Water down the ground really good before you pour.

 

You would be OK unreinforced as long as you had a good, compacted base. Most shops and garages are unreinforced.

If I decided that I was going to reinforce my own I would prolly go with a mat of #3 bar (3/8" dia)

You will need someone to help you lay out cut joints or control joints. Concrete slabs WILL crack....in this way you tell it where to crack.

Mesh is OK if it's in panels. If it's in rolls it is a total PITA.

 

No, do 6" with reinforcement. Sidewalks are poured 4" thick and they always crack when maintenance vehicles and mowers drive over them. We pour driveways and floors at least 6" thick. Any heavy trucks anticipated we do 8" thick, but for what you need ( from what I understand from the above) 6" should be the best option. You pay for the concrete by the yard, plus a delivery charge. The delivery charge stays the same, no matter the quantity, so if you go from 4" to 6" thick (50% more concrete) the price will not be 50% higher.

Prices should be (depending on how far you are from the concrete supplier) about $100 to $200 delivery charge plus $70 to $80 per CY for the concrete.

Remember to keep the floor wet for a day or two to help it cure good (cover with visquine after it is set up)

 

Whoa!
Who's buying the concrete here ? hehehe

We routinely run 360 ton hydro cranes on reinforced 5" slabs.
The heaviest trucks on the highway sit on 7" reinforced slabs when they are loading/unloading.
747's roll on 12" -16" thick runways.

OP, your subgrade should be good compacted crushed rock.
You will have to decide on what kind of weight your slab will see.
Any doubts about 4", then a reinforced 5" is a proven commodity, not a guess.

 

Blah blah blah

Thickness requirement is also determined by reinforcement and concrete MPA

 

3500 PSI concrete is typical here for structural slabs on grade.
Sometimes 4000 PSI if the engineer is a n00b.

 

All I'm getting at is thickness isn't all there is to it .

 

Reality check here

The OP sounds like he has never been anywhere near a concrete pour , and is going to form , place and finish his own slab .

Perhaps hiring a finisher is in order and you and your buddies can be the muscle .

 

I personally don't think reinforcement is necessary for what your doing. What material are you using for your subgrade? Rent a jumping jack, place 4" lifts and make sure it's compacted properly. I would go with a 5-6" slab with a 4000 psi mix. It will be a little more difficult to work with due to the fact that it has a higher PC to H2O ratio. Overkill?...maybe, but at ~$8 more per yard, I feel it's worth it. Make sure to wet the subgrade with a hose prior to placing your concrete. You don't need to soak it, just enough so the subgrade doesn't suck the water content out of your mix. My $.02

 

^^^^^^^
Good advice

 

A friend's cousin poured a 1/4 mile long driveway with himself (unskilled) and a gang of day laborers.
It never saw a tool...they just rodded it off and walked away. It was a multi-thousand dollar, concrete, washboard road. I almost bit the end of my tongue off driving on the thing !

Yeah, the OP needs some finishers if he wants a nice slab.
I mentioned it back in #15.

 

Yea i will be the muscle and financer haha. Have skilled people that will be telling me what to do/helping out

 

Still just in the concept stage trying to figure stuff out

 

I'm just a pump operator. I don't usually have to get dirty right away.

 

Yes, this is my feeling as well.

It's extreme "point loading" that will cause problems and I don't think this slab will ever see that.
Sometimes our cranes will crack the slab at the downrigger pad locations, for example.

Yes, the subgrade prep (and the finish quality) will make or break a slab.
Spend the time and dig out that dirt and replace with compacted, structural fill. We use minimum 6" of 1" minus rock on subrades and often much more.

Everything is "VEed" (value engineered) these days and the more experienced engineers have found that 3500 PSI concrete yields very good performance.
Many 3500 PSI mix design test histories will reveal that they are breaking over 4000 PSI after 28 days.
The OP can ask for these break history printouts at the Ready-Mix company.

Always good advice.

Crack control (control joints) is very important as I have already outlined a couple of posts back.
OP, have someone show you how to do diamond block-outs around and columns or posts out in the slab. Any "unprotected" outside (or inside) corner will project a crack out into the slab.

Also curing is of extreme importance.

Holding moisture in the slab for as long as possible during the curing process is paramount. The critical time frame is the first 7 days.
If drying outpaces curing you will have cracking.

Three ways to do it.....

1. Spray cure
This is a chemical film that is sprayed on the slab as soon as you can walk on it (in tennis shoes, the day of the pour).
I like the non-water base stuff, but it is hard to find.
Make sure that what you use is going to be compatible with whatever sealer you intend to use later.
Go to your local Big Boy Concrete Accessories Store for advice and product. Not Home Depot for this!

2. Cover it
6 mil visqueen
Concrete blankets if there is freeze danger
We avoid this method because sometimes you get scratching and/or random discoloration of the surface of the slab. Often weather forces this, though.

3. Wet cure
In severe hot weather we will cover with GeoTextile fabric and sprinkler-soak for 7 days.
The GeoTextile fabric acts like a giant sponge. It's the evolution of burlap and straw covered slabs.
Straw directly on a slab will cause some nasty stains !

 

If this is a barn floor, then WTF.

Now if this is going to be your pride and joy shop floor you want a Hard Trowel Finish.
This is where you have experienced finishers swingin' steel (steel finishing trowels, hand or power) until that slab is black.
Then 10 years from now when you are sweeping with a fine horsehair push broom, that slab will bring a smile to your face.

If you skimp or fuk up the finish because you didn't have enough experienced people, you will HATE that slab every time you sweep it.
Book it.

OP, everything you need to know is in this thread.

 

I'm going to jump into this discussion if that's okay.

I'm looking to get a concrete patio/parking pad poured this summer. It need to tie into the slab of the house because I will be finishing the structure over approx. 75 sq. ft. of it.

The slab is going to be approx. 25'x25'. I'm guessing 4" thick since it will serve regular duty as a patio with occasional parking.

When I am getting quotes, what ballpark should I be looking in for base, pour and finishing?

 

OP ,I did commercial pours for 4 years in the laborers union & although the smallest one we ever did was still about 240yds (10 guys shoveling like hell w/power skreet & me pulling up the mesh, fucked job) I dont see any harm dropping in a little mesh, but if you have to pump it , it gets pricey..

 

As I already stated, if you use mesh, always try to get in in flat panels.
Rolled mesh is one of the most fukked products ever, for concrete reinforcement because it tries to pop up above the slab.
You fight it during the entire pour......I've been there.

Yes to mesh in flat panels.
A big NO to mesh in rolls.

 

x2