Filling just one cubic yard with concrete and you need upwards of 4,000 pounds of concrete. That’s a lot to order, and it can be very expensive.
The only safe way to mix large amounts of concrete is to use a concrete mixer. However, renting a concrete mixer and buying enough concrete to fill up space can still end up being almost twice as expensive as just ordering ready mix concrete from a local source.
Let me explain: the expensive part of making concrete isn’t the actual mixing, and getting your hands on a mixer should only cost you about a hundred dollars per day. The cost will be in acquiring large amounts of concrete.
The Price Of Concrete
I will be using, as a benchmark for this article, the price to get ready-made concrete delivered to your site.
This price is roughly 113$ per cubic yard if you need 10 cubic yards, and 170$ per cubic yard if you need significantly less than that.
Now the first hurdle we’ll need to cross is purchasing the concrete. We’re going to assume that you need only 1 cubic yard of concrete. First, we’ll need to figure out how much concrete that is.
To fill one cubic foot of concrete, you need 144 pounds of concrete mix. One cubic yard is the same as 27 cubic feet. This means that 1 cubic yard of concrete will need approximately 4,056 pounds of concrete mix.
How much will that cost? Well, as a consumer, you can buy concrete in 80lb bags from your local big box hardware store for 5$ each. If you buy in bulk (which you most likely will) this will decrease to 4$ each.
That comes out to 20$ per pound. That means that we can get the total cost of the concrete by dividing the weight of concrete from the total weight of concrete that we need. If we do this we will come out with a price of about 202$ per yard before tax.
As you can see, this is still thirty dollars more than even the most expensive price for ordering ready-made concrete.
Renting A Concrete Mixer
Surprisingly, this ends up being the easiest part. Now, most concrete mixers can mix up to about two-thirds of their volume at a time. That means that a 3 cubic foot mixer will not be able to mix 3 cubic feet of concrete.
The largest mixers usually available to rent are around 9 cubic meters.
If you do choose to use a small mixer for your project to save money, then you really should have just ordered ready mix concrete in the first place. But if you still want to use a small mixer, you should be prepared to spend a long time on this project.
A mixer that can fit two bags (160lbs) will spend about 5 minutes mixing each batch. For a 1 cubic yard project, that will take 3.125 hours. That’s just mixing. Not pouring, formwork, or anything else.
So you need a larger mixer to mix your two tons of concrete. For just four hours, it will cost you about 70$. You can add that to your total cost. Your pour now costs 272$, and you’ve officially wasted an entire Ben Franklin’s worth on pouring one cubic yard of concrete.
Transporting The Concrete
So you’ve purchased your 4000lbs of concrete and rented a concrete mixer. How do you move it from the hardware store to your home?
If you insist on driving it home in your car, it will take you a good number of trips. It may be easier to have it delivered in a semi-truck, which will of course cost money.
Whatever added fees you get from transportation are not likely to be worthy of neglect. Because of the various prices of things like gas and deliveries, I’ve neglected to calculate that here.
But if you really want to go through with this two-ton concrete mixture project, you should be sure to do them on your own time.
Mixing The Concrete
So you’ve made it all the way here. Either your morbid curiosity has carried you to this point or it was your sheer stubbornness. I cannot stress enough that it is not a good idea for you to mix a large amount of concrete on your own. It’s expensive, time-consuming, and possibly even dangerous.
This is probably the simplest part of the entire process. You have a cement mixer to mix the concrete in, you have multiple tons of concrete, you have your garden hose ready to pour out an entire pond to make this all work. What do you actually have to do?
Well, it will depend on what type of mixer you have, and the kind that is commonly rentable is known as a batch mixer.
Batch mixers mix one batch of concrete at a time. Depending on the amount of concrete you need, they can end up being quite convenient. Generally, if you need less than 6 square feet of concrete, they’ll work just fine.
If you’re mixing a whole square yard of concrete, however, this will not be the case. One square yard of concrete weighs about 4,056lbs dry, and so in order to mix all of the concrete that you need for your concrete you’ll need to mix several batches total.
How To Use A Batch Mixer
Batch mixers are fairly simple to use. Here’s a quick rundown.
- Add in the dry mix
- Add in the appropriate amount of water
- Turn on the mixer
- Wait five minutes.
- Check to make sure if the concrete has the right amount of water. If there’s not enough, add a tiny bit more. If there’s too much, add a little extra powder. Repeat steps 3 and 4. Otherwise, move on.
- Pour the concrete.
- Repeat until finished.
You will also want to wash the machine out if it’s ever going to be turned off for more than a few minutes. It’s probably a rental, and you don’t want to end up responsible for damaging it.
You’re In It For The Long Haul
You’ll most likely be spending a couple of hours on this project. You’ll want to find people to help you so that you don’t end up hurting yourself. Hopefully, you have children or neighbors who can provide some service so that you don’t have to pay them.
If not, you’ll want to look at hiring some contractors to help with the manual labor of pouring, mixing, and pouring again. However, at the point where you’re hiring contractors, you might as well just order ready mix concrete anyways.
Here are some tips for if you go ahead with the project:
- Take turns mixing! If one person is stuck on the mixing duty the whole time, they’ll get exhausted and bored. Keep things moving by making a rotating schedule.
- Mix batches that are as big as your mixer can handle. The bigger the batches you mix, the fewer batches you’ll need.
- Be consistent. The more batches you mix, the more likely there is to be a mistake at this point. To make sure this doesn’t happen, make sure that you’re consistent in measuring the amount of water that goes into each batch of concrete. Not doing so can cause discoloration to occur in the future.
The biggest tip I can think of though is to just not do it. It will almost certainly be both cheaper and easier to order ready mix concrete to be delivered by a concrete mixer truck to your home instead.
Mixing more than just a few cubic feet of concrete on your own is a fool’s errand. Please do not make this mistake!
Despite all of this, I really don’t think that it’s always necessary for you to get a contractor to do your concrete work for you. Contractors will increase the price of your project significantly.
If you only need a few cubic yards poured, you and your friends can probably do all of the floating and forming that you need to do on your own with the right planning and effort.
If you plan to do a project on your own in the near future, here are some things that you should be thinking about:
- How big should your form be? This will determine the amount of concrete you end up using.
- Do you know how to float concrete? If not, you should look up instructions and try a few small projects as practice.
- Has anyone close to you ever worked with concrete before? If not, then, as with the previous suggestions, you should try a few small practice projects.
- Are there any trees near the space you plan to pave? If there are, you might want to figure out if your project may damage them.
- Is your project in an enclosed space? If so, will you need to remove an already existing floor? When do you need to do that to keep on schedule?
There are a lot more questions you’ll need to be asking yourself. But, as long as this project isn’t enormous you should be able to finish it all on your own with minimal help from expensive contractors!
Just don’t try to mix all of your concrete on your own. It will not work out the way you want it to.