Concrete
A concrete slab is one of the few home projects where the finished product looks identical no matter who poured it, and stays that way for about five years. The differences between a good slab and a cheap one are almost entirely below the surface, which is why this is such a difficult thing to buy well.
We are not going to publish a national price per square foot here. Concrete is delivered by truck from a local plant, placed by local labour, and priced against local disposal and permit costs, so a single national figure would be wrong nearly everywhere it was read. What follows is the structure of the bid - the things that actually move the number - and then a pointer to real metro-level pricing.
Two secondary factors move real money on residential jobs and rarely appear in an advertised price: access and finish. A truck that can reach the pour is a different job from one that needs pumping or wheelbarrows across a garden, and a broom finish is a different job from a stamped, coloured or polished one.
When one bid is dramatically under the others, it is worth finding out which of these it is, because the honest answers and the worrying answers look the same on a one-line quote:
Only the last two are visible to you after the fact, and only for a while. This is why the specification matters more on concrete than on almost any other trade.
Concrete shrinks as it cures, and shrinking concrete cracks. That is not a defect, it is material behaviour. The purpose of control joints is to decide in advance where those cracks happen, so they occur in a straight tooled line instead of wandering across the middle of a patio. A contractor who promises you a slab that will never crack is either not being straight with you or does not know the material. The right promise is that the cracking will be controlled, and that hairline cracks in the joints are the system working.
If you want to verify a claim without reading a sales page, the industry's own technical bodies publish freely. The American Concrete Institute writes the consensus standards that specifications reference, the National Ready Mixed Concrete Association represents the plants that batch and deliver the mix, and the Portland Cement Association publishes background material on the cement itself. None of them will quote your job, but between them you can check whether a term on your bid is a real specification or a marketing word.
Ask every bidder the same five things, in writing, before anyone visits:
A crew that answers all five without hesitating is quoting the job. A crew that will only give you a headline square-foot rate is quoting the visit.
For actual figures rather than a national average, look at a metro breakdown and read the line items. The concrete crew we recommend in California publishes a 2026 price guide for concrete work in Los Angeles that itemises the same variables listed above. Los Angeles rates will not be your rates if you are elsewhere, but the structure of the estimate is the same everywhere - only the local labour, disposal and permit costs change - so it is still the most useful thing to read before your first bid arrives.
Usually because they are not quoting the same slab. Square footage is only one of four numbers that set the price - the others are thickness, what goes underneath it, and what reinforcement is in it. A four-inch slab on compacted base with mesh and a six-inch slab on engineered fill with rebar are different products that occupy the same footprint. Until all bidders state those three things, you are comparing a number to a different number rather than a bid to a bid.
No - it is the better buy for the load you actually intend to put on it. Thickness is specified against use: foot traffic and patio furniture ask far less of a slab than a parked vehicle, and a vehicle asks far less than an RV, a boat trailer or a workshop lift. Paying for six inches under a garden patio is wasted money, and paying for four inches under anything heavy is money you will spend twice.
Less than most homeowners expect. The delivered material is a real line item, but excavation, grading, compaction, forming, reinforcement, placement labour, finishing and disposal of whatever was there before frequently add up to more than the mix. This is exactly why a bid that is low by a large margin is more often a thin sub-base or skipped prep than a discount on concrete.
It depends on load and slab geometry, and it is a question for whoever is stamping the job rather than a rule of thumb from a website. What is worth knowing as a buyer is that reinforcement is not optional decoration and it is a common place to quietly save money on a bid - so ask for the reinforcement type and spacing in writing, and confirm it is being held up off the ground rather than laid on the dirt, where it does nothing.
Weather changes the method more than the price. Very hot, very cold and very windy conditions all need specific handling - timing, curing protection, sometimes admixtures - and a crew that has a plan for the forecast is telling you something useful about how they work. A crew that treats a heat wave as a normal Tuesday is not.