The basic cost of a 40' x 60' concrete slab that's 6" thick is between $8 and $12 per square foot.
That give you a range of $19,200.00 to $28,800 depending on the cost of materials and labor in your area.
If everything else is the same and all you're doing is comparing the cost of a 6" slab VS a 4" slab, the cost would drop about $2400.00.
This is because you're using about 16 cubic yards LESS on a 4" slab compared to a 6" slab. You'll save on the cost of using less concrete.
I'm basing my figure on using a price of $150 per cubic yard of concrete.
For a 6 inch thick concrete slab:
The cost of 3000 psi concrete per yard generally cost $150.00 per cubic yard. (pricing will vary in your area, check with your local ready-mix supplier) $3.00 per sq ft
Light gauge wire mesh generally cost about $18.00 for a 5' x 10' sheet. $.36 per sq ft
Fibermesh in the concrete will add from $5 - $8 dollars per cubic yard of concrete $.13 per sq ft
#4 or 1/2" rebar costs about $12 per 20 foot long piece (21 pieces) $.10 per sq ft
50 anchor bolts 6" length costs $75 $.03 per sq ft
1.25 rolls of 20' x 100' 6 mil poly vapor barrier $150.00 $.07 per sq ft
Total cost of materials: $3.71 per sq ft
The cost of labor to form, pour, finish, and saw cut the slab makes up the rest or approximately $5.00 - $9.00 per sq ft
Note: I'm showing you these costs based on my pricing in my area. What I pay for materials and what I pay my labor will be different than what other contractors charge to you the customer.
Use my 40'x60' concrete slab cost as a general guide to inform yourself and expect to get higher or lower pricing where you live.
My concrete slab pricing above doesn't include the following things:
My concrete slab prices above will give you a rough estimate as to what your actual slab cost will be.
Depending on who you get estimates from, your local contractor could have much higher labor costs, materials costs, and profit margins than I do.
I would recommend getting 3 estimates if you can. One of the best ways to find concrete slab contractors in your area is to contact your local concrete ready-mix supplier.
These are the companies that deliver concrete to contractors like me. They know who the better concrete slab installers are in your area.
Google "ready mix concrete near me" and a list of concrete companies will show up.
Call 1 or 2 of them and ask for the best concrete slab guys they deliver concrete to.
Ask each contact what their 40x60 concrete slab cost is and make sure you compare prices using the same specifications to get accurate estimates.
In the video below I'm installing a 40' x 50' concrete slab for a customer. I would pour a 40 x 60 slab the same way.
This slab has 12" thick edges which added to the cost like I mentioned above.
Be careful using slab cost information from some of the "HOME" sites on the web.
I checked out their "concrete slab costs" for a 40x60 slab and the pricing was all over the place. I would say they're not very accurate and don't really articulate what the actual cost would be.
I'm not sure where they're getting their costs or pricing from but it's not from an actual concrete contractor like me.
Having said that, use my slab costs as a guide only. I live in Maine and the costs of living is different here than in NY, CA, FL or other states.
My goal is just to provide you with some information as a base line of costs for a particular size concrete slab.
FOR MORE INFORMATION ON CONCRETE SLAB COSTS:
How much does a 30' x 30' concrete slab cost?
How to calculate the cost of a concrete slab.
How much does it cost to pour a 50' x 34' concrete floor for a basement?