Whether you’re a DIYer or a professional builder, it’s important to have a detailed budget outlined before you dive into the work. There’s no worse feeling than beginning a project and then having to let it sit unfinished due to a lack of funds.
Concrete prices tend to have people scratching their heads. How much concrete is needed for a particular purpose? What kind of concrete should you get? Do you need to have the concrete delivered in a ready mix truck, or can you buy it by the bag and mix it by hand? Will you need to color or stamp the concrete?
All of these considerations can drive up the cost of concrete, or at least the cost of your overall project. To help you come up with an estimation for your concrete needs, we’ve put together this guide to teach you how to calculate concrete requirements and determine the concrete cost per yard.
But first, we must start with a caveat: the concrete prices mentioned in this guide might be different to what is available in your area. They serve as a guideline for your initial estimates, but in order to really nail down an accurate budget, you’ll need to consult your local supplier. The cost of concrete varies by location according to the rules of supply and demand.
With that in mind, let’s talk about the first thing you need to know: what type of concrete does your project require?
Concrete Prices Depend on the Type of Concrete
The most basic concrete mixtures are composed of Portland cement, aggregate (rough materials such as gravel or sand) and water. But depending on the purpose of the concrete, different materials can be added to the mixture to give it various properties, such as slowing or increasing the drying time, affecting the viscosity to make it easier to move around, or simply making it resistant to water damage.
Determining the right concrete mixture for a specific purpose is an art (or rather, a science) known as mix design. The extra ingredients added to the basic components of cement, aggregate and water are known as admixtures.
If you are installing a patio, driveway or concrete slab, chances are you don’t need to worry about admixtures. Admixtures are typically needed for special circumstances.
But one thing to keep in mind is whether or not you plan to stamp the concrete, as this often requires a slower drying time and thus needs an admixture to affect the concrete’s water retention. The weather when pouring concrete can also make a difference in drying time.
Also decide whether you will be able to pour the concrete directly where it is needed, or whether you will need to move it around once it has been poured. Concrete quickly becomes tough to move the more you move it, but in some cases it is impossible to avoid transferring the concrete. An admixture that improves the workability of the concrete can be extremely helpful.
A good rule of thumb is to talk about your needs with your local ready-mix supplier, such as Tex Con Ready Mix, to determine whether any admixtures are necessary for your concrete installation. You will also be able to get a cost estimate at the same time.
How to Calculate Concrete Cost
When you talk to your local ready mix supplier about the type of concrete you need, they’ll likely give you the concrete cost per yard or per cubic yard. But how many cubic yards will your project require?
A cubic yard is calculated by multiplying the length, width and depth of your concrete in feet, then dividing by 27. To help you accurately calculate concrete cost, you can use Tex Con Ready Mix’s concrete cost calculator. You may need to make some sketches and do some additional math in order to estimate how many cubic yards are in an irregularly shaped driveway or patio.
This brings up another important point: how thick should your concrete be? A general rule of thumb is 4 inches for an average patio or driveway. If you foresee any reason why your concrete slab may need to hold up to heavy loads, like a dump truck or other heavy machinery, increase the thickness to 5 or 6 inches. For technical purposes, it’s best to consult with an engineer to be certain the concrete is strong enough.
Now that you know how thick your concrete will be, you can complete the equation to determine the number of cubic yards. Finally, add about 5% to the total yardage in order to have a small amount of extra concrete on hand in the event of spillage.
Now, for the price. According to the National Ready Mixed Concrete Association, concrete prices in the U.S. in 2014 averaged out to $98.23 per cubic yard.
What Else Do You Need to Pour Concrete?
Now that we’ve talked about the cost of concrete itself, you should have a decent idea of how much you’ll spend on raw materials. But if we stop there and don’t consider the other costs associated with pouring concrete, your final bill will look very different.
Thanks to its versatility and viscosity, pouring concrete is not the most challenging aspect of installation. Preparing the site to receive and support the concrete is a task for a patient and precise person. Cutting corners at this stage will result in subpar concrete, but that is another topic altogether. In short, there are labor and material costs that must be taken into account to get a true picture of how much concrete costs.
Here are some other services or products that you may need to purchase, depending on your goals:
Cost of a Concrete Slab
Let’s take all of this information and make a sample budget to determine the cost of a concrete slab, which we plan to install ourselves in order to save on labor costs. Our slab will be 36 feet by 48 feet and will serve as the base for a barn. We might have to bring a tractor into our barn at some point, so we plan to make our concrete slab 6 inches thick.
First, we need to convert everything to feet (ft). 6 inches = 0.5 feet. Now we can multiply 0.5 ft X 36 ft X 48 ft = 864 cubic feet. To convert that to cubic yards, we need to divide our total by the number of cubic feet in a cubic yard, which is 27. That gives us 864 / 27 = 32 cubic yards.
We’re going to anticipate that some of the concrete might spill outside of our concrete forms, so we’ll add 5% of 32 to our calculated cubic yards, giving us a grand total of 33.6 cubic yards of concrete to make the foundation for our barn.
Our local ready-mix concrete supplier sells standard ready mix (no special admixtures are needed for our concrete slab) at the national average of $98.23 per cubic yard, which means it will cost $3,300.53 for the concrete.
Now, for other requirements:
Fortunately, our local ready mix supply company offers free delivery, and our concrete slab does not need to be decorative. In the end, our concrete project costs about an additional $1200 above and beyond the cost of the concrete itself.
Using your own specifications, draw up a detailed list of requirements and get estimates on everything in order to see how much your project will cost. Because the price of concrete, gravel, lumber and even rebar vary by region, there’s no way to give a detailed cost estimate that will fit every reader. But we hope this guide has opened your eyes to some of the hidden costs of installing concrete, and will help you make a useful budget for your next project.