How to Price Concrete Work for What Actually Goes Wrong

Concrete doesn't give you a do-over. Once that truck dumps and it starts to set, you're committed. That's exactly why learning how to price concrete work correctly matters more than in almost any other trade. A bad number on a paint job costs you a slow week. A bad number on a pour can cost you the whole job in one afternoon.

Let me walk through how I price flatwork so the stuff that always goes wrong is already baked into the number.

Start with cubic yards, and don't shortchange it

Concrete is sold and poured by the cubic yard, so your first job is volume. The formula is length times width times thickness, all in feet, divided by 27 to get cubic yards.

A 20 by 30 foot slab at 4 inches thick: 20 times 30 is 600 square feet, times 0.33 feet (4 inches) is about 200 cubic feet, divided by 27 is roughly 7.4 cubic yards.

Now here's the mistake. You never order exactly 7.4. Subgrade is never perfectly level, and a slightly deep spot drinks concrete fast.

• Add waste, usually 5 to 10 percent. On that slab, order 8 yards, not 7.4.
• Running short means a second short-load fee and a cold joint where the pours meet. That's ugly and weak.
• Thicken your estimate where the plan calls for it. Driveways and anything bearing vehicles often want 5 or 6 inches, not 4. That's more yards.

Price the material at your real delivered cost per yard, including any short-load fees, Saturday fees, and long-wait charges the plant tacks on. Those are real and they're on you.

Prep and forming is where the labor hides

The pour itself is fast. The days before it are where the labor lives, and it's the part guys forget when they figure out how to price concrete work.

Before any concrete shows up you've got:

• Excavation and grading the subgrade to the right depth and slope.
• Base material, hauling in and compacting gravel so the slab doesn't heave or crack.
• Forming, setting and bracing lumber or steel forms dead level and square.
• Rebar or wire mesh, and any vapor barrier under an interior slab.

This is real time and real material. Forming a cut-up patio with curves takes way longer than a straight rectangle. Bad access, where you're wheelbarrowing concrete 80 feet because the truck can't reach, can double your pour labor. Walk the site and price the access honestly. A pump truck might be cheaper than four guys running wheelbarrows all day, and it's a line item, not a surprise.

Finishing labor is skilled and time-boxed

Here's what makes concrete different. Once it's down, the clock is running and you cannot slow it. You've got a set window to screed, float, edge, and finish before it hardens. Miss it and the finish is ruined for good.

That means finishing has to be staffed for the size of the pour. A 7 yard slab needs enough experienced hands to finish it all before it sets, in whatever weather you've got. Underman the crew to save on labor and you'll get a bad finish you can't fix.

Price finishing by the type, because a broom finish is fast and a stamped or exposed-aggregate finish is a different world of labor:

• Broom finish: standard, quickest.
• Smooth trowel: more time, more skill.
• Stamped or colored: significantly more labor, plus release agents, sealers, and stamp mats.
• Exposed aggregate: wash timing is critical and adds hours.

Match the crew size and skill to the finish and the yardage. That's the part that protects both your margin and your reputation.

Weather, waste, and the change orders that eat you

Concrete lives and dies by conditions. Pour in 95 degree heat and it sets too fast, so you need retarder and more hands. Pour in the cold and you're renting blankets or adding accelerator and protecting it from freezing. Build a weather buffer into your schedule and your price, because you can't pour a good slab in the rain and a washed-out pour is a total loss.

Then there's the stuff that turns a clean flatwork job into a money pit:

• Bad subgrade you didn't see until you dug. More base, more compaction.
• Buried surprises, old footings, tree roots, a forgotten sprinkler line.
• Access problems that force a pump or extra labor.
• Owner changes: a bigger patio, a different finish, an add-on step.

Put unit prices in the contract for the likely surprises. Price per extra yard, price per foot of extra excavation, price for the pump if it's needed. When the ground fights you, it's a documented change order, not an argument in the driveway with a truck full of concrete waiting.

Total it like a pro

Stack your number: material with waste and plant fees, excavation and base, forming and reinforcement, the pour labor and access, finishing to the spec, then overhead and profit on top. Cover control joints, curing, and cleanup too.

Concrete rewards the estimator who thinks about the whole day, not just the yardage. Price the prep, staff the finish, buffer the weather, and put the surprises in writing before the truck ever backs up the drive. Do that and the pour that ruins other guys is just another Tuesday for you.