The complete estimator cost guide for concrete
You’re about to begin a new project, and concrete plays a major role in it.
Yet, before you begin pouring and mixing, you’ll need to measure out your materials.
While this should be a simple step, there are special elements of concrete composition that make it a little more challenging to measure.
Are you wondering, “How much concrete do I need?”
If so, you’ve come to the right place. We’re dedicated to helping our customers navigate the tricky and technical details of concrete so they can get to work quicker.
Today, we’re sharing a quick guide to help you measure your concrete the right way, every time.
Ready to get started? Let’s dive in! These are basic volume measurements.
Materials to Gather
Before you begin this tutorial, it helps to have all of your materials in place and ready to go.
The materials that go into creating a batch of concrete include:
- CementAggregate (washed and crushed rock)SandWaterBucket
Most contractors stick to a simple four-two-one ratio when mixing their concrete. This means they’ll pour in four parts aggregate, two parts sand, one part cement.
While these variables are relatively predictable, water proportions can fluctuate some. A few of the factors that help determine how much water your batch needs include:
- The outdoor air temperature, humidity level, the amount of direct sunlight, the concrete mix ratio
As you add more water, remember that you’re weakening the concrete’s cured tensile strength. This means it’s more susceptible to breaking under tension.
Projecting Concrete Measurements and Costs
There are a few steps to follow to help you determine the amount of concrete you’ll need to mix for your projects.
Step 1: Determine Concrete Thickness
Before you get too far into the process, how thick do you want your concrete to be?
Different applications will require different measurements, so consider how you plan to use the surface after the concrete hardens.
Let’s review a few common concrete slabs scenarios to keep in mind.
Standard Concrete Sidewalks
Pour these around four inches thick. If the sidewalk crosses a driveway, make it eight inches thick. The same measurements apply if service vehicles will use the sidewalk.
Residential Driveways
As long as they’re only intended for average vehicles, pour these at least six inches thick.
Commercial Driveway Aprons
Pour these at least eight inches thick. Ideally, try to make them around 10 inches, as this will allow trash trucks and other utility vehicles to use the surface without damaging it.
Dumpster Pads and Concrete Loading Docks
Pour these at least 10 inches thick, increasing it to 12 inches where you anticipate heavy loads.
Concrete Footing and Foundations
Measures beam volume then slab area
Step 2: Measure Your Surface Area
Once you know how thick you need your concrete to be, you can go ahead and measure the area you’ll need to cover.
Take the length and width measurements and write them down.
Step 3: Calculate the Square Footage
With your measurements in hand, multiply the length by the width. This will provide you with your total square footage.
For example:
10 feet x 10 feet = 100 square feet
Step 4: Convert Your Thickness Metric
Remember Step 1 above? By now, you should know how many inches thick you’ll need your concrete to be. Use an online calculator such as this one to convert that number into feet, instead.
Here are a few examples:
- Four inches=0.33 feet
- Six inches = 0.5 feet
- Eight inches = 0.66 feet
- 10 inches = 0.83 feet
- 12 inches = 1 foot
Step 5: Calculate Cubic Feet (total volume of concrete)
Now that you’ve converted your desired thickness from inches to feet, take this measurement and multiply it by your total square footage determined in Step 3 above.
Using the example above, your calculation might look like this:
100 x 0.5 = 50 cubic feet
Step 6: Convert Cubic Feet to Yards
There are 27 Cubic feet in a yard. You can get 10 yards in a ready-mixed concrete truck
With your total cubic feet measurement in hand, you’ll need to convert this measurement to cubic yards.
To do so, multiply the measurement by .037.
Once you know the total yards of concrete you need, you can use this number to gauge how many raw ingredients or pre-mixed bags you’ll need to complete the project.
Continuing the example, your calculation becomes
50 x .037 = 1.85 cubic yards of concrete required.
Step 7: Measure How Many Bags of concrete You Need (estimate the amounts)
If you’re using pre-mixed bags, you’ll notice that each bag has a distinct yield. The most common types are 40 pounds, 60 pounds, and 80 pounds.
Here are the average yields for each size:
- 40-pound bag: .011 cubic yards
- 60-pound bag: .017 cubic yards
- 80-pound bag: .022 cubic yards
Knowing this, you can take the total number of cubic yards you need for your project (Step 6 above) and divide it by the average yield size to see how many bags you need for your project.
In our example, we calculated that we’d need 1.85 cubic yards of concrete.
Remember any time you order less than a full truck there are short load fees
If you buy a 40-pound bag, it will take around 167 bags to fulfill our needs.
If we buy a 60-pound bag, it will take 111 bags.
For an 80-pound bags, we will only need around 84 bags.
If you are a concrete contractor and hire a ready-mix truck then be aware that you should account for about 10% waste rate. Once you figure out your yardage remember there are 10 yards in a truck and add the waste factor.
Concrete pumper
Do you need a pumper or are you going to wheelbarrow the concrete? Most ready-mix drivers may give you 2 minutes per yard to unload the truck. Depending on your wheelbarrow size it could take 9-14 wheelbarrow loads per yard.
So you better have 4-5 guys with wheelbarrows. If you can shoot it off the truck great. Keep in mind the weight of an existing concrete truck will break most concrete surfaces it will drive on.
I good driver will not drive through the dirt as the probability of getting stuck is high, especially after rains.
So it’s a good idea to hire a pump truck too($1000 and up) to pour large foundations or someone with an inline pump ($600-875) for smaller projects)
There’s either the expense of using a pump or the labor of offloading by hand. My recommendation is to get a pump, Do you want to waste time while the clock is ticking and you are justing going to wear out your team right before you need them most. It’s risky doing it any other way.
Calculator estimates
Rather than buying some concrete calculator and worrying about the setting’s concrete functions, just use our online tool.
“How Much Concrete Do I Need?” Now You Know!
Undertaking a concrete project can be a challenge. You shouldn’t have to spin your wheels and dwindle your resources by asking, “How much concrete do I need?”
Though the process can be laborious, taking the time to figure out your exact needs beforehand can save you from costly and time-consuming errors down the road.
Consider your required thickness, measure your square footage, and perform the necessary calculations to get the metrics right the first time.
Does all of this sound like a chore? It is. And very risky the more you have to pour.
Why not hire a professional contractor to take care of the legwork for you? This way, you can make sure the finished product is top quality.
When you’re ready to take this next step, we’d love to help. We have a vast network of contractors ready to tackle your next concrete project, from countertops to stamped sidewalks. Contact us today to get in touch with an expert you can trust!