How to make concrete
By Tom Drake | 29th November 2024 | 4 min read
Whether you’re building a shed base, a garden path or a front step, learning how to make concrete is a useful DIY skill. In this guide, we show you how to make concrete using a cement mixer and by hand.
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Do I need a cement mixer to make concrete?
If you need to make a small amount of concrete, you can mix it by hand. If you’re going to be mixing a lot of concrete, or you think you’ll be doing a lot of concrete jobs, it can be worth buying or hiring a cement mixer.
Concrete mix ratios
Concrete can be made with cement, sand and aggregates, or cement and ballast, which is a mixture of sand and aggregates. The ratio of sand and aggregates to cement will affect the strength of your concrete mix.
A popular concrete mix ratio is 1:2:3, with 1 part cement, 2 parts sand and 3 parts aggregates (or 1 part cement and 4 parts ballast). For help choosing the right concrete mix ratio for your job, take a look at our concrete mix ratio guide.
How to make concrete with a cement mixer
Here, we outline how to make concrete using a cement mixer. Remember to read and follow the safety precautions for your mixer and wear gloves, safety glasses and a dust mask. Wet cement can cause burns, so always wash your hands after handling concrete and wear protective clothing.
1. Start the mixer
Once you’ve got your materials ready, place your cement mixer on level ground and point the drum up to a 45-degree angle. You can then switch the mixer on.
3. Add half the materials
Add half the cement, sand and aggregates that you’re going to mix up into the drum. Let these materials mix together dry for 2 minutes.
4. Add water
After two minutes, start slowly adding water to the mixture until you achieve the right consistency.
When mixing concrete, you want to create a mixture that isn’t too dry or too sloppy, similar to thick porridge. We have more information below on achieving the right consistency.
5. Add the rest of the materials
Once you’re happy with the consistency of the mixture, add the other half of your materials. Allow them to mix with the existing mixture, then slowly add water until your concrete has the consistency of thick porridge. If you're struggling to get your concrete the right consistency, take a look at the section on adjusting your concrete mix.
Once your concrete is ready, keep the cement mixer running for a few more minutes before pouring.
How to mix concrete by hand
Although it can be harder to achieve a good mix, you can mix concrete by hand if you don’t have a cement mixer available, or you’re only mixing small volumes. When mixing concrete, remember to wear safety glasses, gloves and an appropriate dust mask.
1. Mix sand and aggregates
Once you’ve measured out your sand and aggregates to the correct ratio, place them on a hard surface such as a mixing board or a piece of plywood.
Next, use a shovel to mix the sand and aggregates. Continually fold the pile over, making sure you scoop from the bottom and sides of the pile to ensure the materials are mixed completely.
Keep mixing until the pile of materials is a consistent colour, with no pockets that haven’t been mixed.
2. Add cement
Once you’ve completely mixed the sand and aggregates, add cement to the mix.
With the cement added, take your shovel and mix the materials again. Fold the pile over continuously until all the materials are mixed and the pile has a consistent, even colour.
3. Add water
With the materials mixed, it’s time to add the water. Bring the materials together in a neat pile and create a crater in the middle. You can then add the water to the middle of this crater. Add a small amount of water first, you can add more later if required.
4. Mix in water
With the water added, use a shovel to move the mixture over the top of the crater and mix the water and materials together. Remember to scoop materials up from the sides and bottom of the pile to ensure the water and materials have completely mixed.
As you mix the concrete, add more water when necessary to achieve the desired consistency. The concrete should have the consistency of thick porridge, not too dry and not too sloppy. Once your mixture has achieved the correct consistency and there are no patches of dry material, your concrete is ready to use.
Achieving the right concrete consistency
When you’re mixing concrete, adding the correct volume of water is key to achieving a good mix. A good concrete mix will have the consistency of thick porridge.
You can test the consistency of your mix by picking it up with a gloved hand and squeezing it. The mixture should keep its shape but also release easily from your hand. If it oozes a lot of water, the mixture is too wet and if the mixture crumbles, it’s too dry.
How does the concrete move around the cement mixer?
If you’re using a cement mixer, keep an eye on how your mix is moving around the drum. This can be a good indicator of whether you’ve used the right amount of water.
Your mix should ‘tumble’ around the mixer without sticking to the sides. If your concrete sticks to the side of the drum and only falls when it reaches the very top, it’s too dry. If your mix doesn’t reach the side of the mixer before tumbling back down, it’s too wet.
Adjusting your concrete mix
Even if you measure your materials out exactly, it can still be tricky to get the correct ratio of materials and water. However, you can adjust your concrete as you go to ensure you get the consistency correct.
Concrete is too dry
If your concrete mix is too dry, add small amounts of water until the materials mix with the water.
Concrete is too wet
If your mixture is too wet, add small amounts of cement, aggregates and sand in the same ratios as before until the mixture thickens.