How to Mix Concrete for a Fence Project

How to Mix Concrete for a Fence Project

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Most fence companies who install their fence posts in concrete and who work on larger projects use ready mix supplied by concrete companies. If they do mix concrete on site, they might use premixed sand, stone, and cement to save time.

However, if you’re planning to install your own fence as a DIY project, you might not have access to those types of ready-mixed concrete. That means you probably need to know how to mix concrete for a fence project. Here’s how you can get your fence concrete right.

What Is Concrete?

Before we get into the specifics of how to mix concrete for a fence project, it’s a good idea to clarify what concrete is.

Concrete is a mixture of sand (fine aggregate), stone (coarse aggregate), and cement, which is a powder that has a chemical reaction when mixed with water. It’s that chemical reaction that causes concrete to harden, and it’s why the amount of water you put in your concrete is so important. Too little, and the reaction won’t happen properly. Too much, and your concrete will be too weak.

Concrete has been around for a very long time. In fact, the ancient Romans built things like the Coliseum with early concrete – and since that’s still standing, that’s a great testament to the durability of concrete through the ages.

Probably the best way to describe concrete is that it is a liquid stone that hardens over time. It keeps hardening for a very long time too. In fact, if you test the compressive strength of concrete at seven days, 28 days, and beyond, it will become stronger as time goes by.

What Mix Ratio Do You Need for Concrete?

As you now know, concrete for your fence is made up of sand, stone, cement, and water. But because concrete is a very complex chemical compound, it’s very important that you get the mix proportions right.

Most cement bags will have “recipes” or mix proportions on them, but for a standard fence project, you are probably safe with a mix of one part cement, two parts sand, and four parts stone.

When adding water to this mix, be careful to add as little as possible to get a workable mix. You want the concrete to be properly mixed and able to flow into your footings but not so water-logged that it becomes weak.

Commercial concrete suppliers measure how much concrete “slumps” as part of their quality assurance processes. A slump test measures how much concrete will spread out and “slump” when it is released from a vessel when wet. Usually, the less slump your concrete has, the stronger it will be.

It’s usually a good idea to add water slowly, mix your concrete a little, and then decide if you need more water to get to the right consistency. But whatever you do, your concrete should be more like peanut butter than soup!

Some concrete mix recommendations will give you quantities in bags and cubic meters or cubic feet, but parts is a lot simpler for most people. What that means is that if you use one bucket of cement, you should use two of the same bucket of sand, four of the same bucket of stone, and so on.

Measuring your concrete “ingredients” like that makes it easy to mix the right amount of concrete for your project and to avoid waste.

How to Mix Concrete

Now that you have some idea of what concrete is, what goes into it, and what proportions of the different ingredients in concrete you need, the next big thing you need to know is how to mix concrete.

The first thing you need to know is that you need to be extra careful when working with concrete.

Breathing cement dust in can be very dangerous, and concrete is a very strong base or alkaline substance, and it can give you burns just like you would get from acid.

So before you start working with concrete, make sure you have appropriate face masks, safety glasses, gloves, and other protective gear. Make sure you also have clean water available in case you need to wash concrete off your skin while you work.

There are several ways to mix concrete; the one you choose will probably depend on how much you need to mix. Some of the options are:

  • Hire a concrete mixer if you want to mix larger quantities of concrete – these work like a large food processor, quickly and thoroughly mixing the concrete to an even consistency
  • Use wheelbarrows and spades to mix smaller quantities of concrete – the wheelbarrow makes it very easy to move and place the concrete
  • Use a sheet of plywood to protect your lawn or paving, and mix the concrete on the plywood. This is a very low-tech way of mixing concrete, but you can move the plywood along your fence line as you work, so you can mix small batches as you go along

Try to mix only as much concrete as you are going to use at one time, and be sure to store any leftover cement in a dry place that is protected from the weather and on a pallet or otherwise elevated off the ground. If cement gets wet, it will harden and become useless.

Tips for Working with Concrete

Now that you know a little more about how to mix concrete for your fence project, it’s worth discussing a few extra tips that can help to make your project a little more successful:

  • Don’t mix concrete until you’re ready to pour it – concrete starts to set as soon as the water is added, and if you leave it standing around on your fence project, it will probably harden before you can use it
  • Choose a smaller size of stone for your concrete mix – this makes it easier to pour your concrete into your holes and for it to flow around posts and other fence elements
  • Try to avoid getting any air trapped in your concrete – these are called “voids,” and they will weaken your concrete
  • You can use a concrete vibrator to get rid of air in your footings if you are concerned about voids
  • Concrete needs to have a constant, slow supply of moisture during the hardening process to make sure it reaches the desired strength – so even after the initial setting is done, water your concrete a little to keep it moist
  • Concrete does not like extreme weather – too hot, and it will dry out too quickly, and too cold and the water will freeze before it can set properly

We hope these concrete tips will make your fence project a little easier and ensure that you get a sturdy and durable finished product.

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