Postcrete and concrete may sound very similar, but they have several key differences.
Postcrete, or post-mix concrete, doesn’t require mixing and sets in five to ten minutes. It’s ideal for small projects like fence posts and rotary washing lines. Concrete requires precise preparation, takes 24 to 48 hours to set, and is best for large construction projects. When purchased in bulk, concrete is cheaper, but may involve additional costs like a concrete mixer.
Continue reading to learn more about these two materials and which may be the better choice for your project.
What Is Postcrete?
Postcrete, which is also called post-mix concrete, is a blend of concrete ingredients that requires no mixing or preparation before use.
It’s ready to use straight from the bag and contains special additives that make it ideal for setting concrete, metal, or wooden posts into the ground.
What Is Concrete?
Concrete is a frequently-used engineering material that’s utilised for a variety of construction applications. It’s a composite material made up of cement, water, and an aggregate.
These three ingredients must be mixed together in the appropriate ratios before the concrete is used for a project.
Postcrete Vs. Concrete: Similarities And Differences
Now that we’ve covered the definitions of Postcrete and concrete, let’s compare and contrast their characteristics.
|Small projects, such as various types of concrete, metal, and wooden posts
|Large projects, like buildings, roads, foundations, bridges, sewers, and driveways
|Sulphates, calcium aluminates, calcium silicates, lime, alkalis, chlorides, chromium compounds, sand, and minerals
|Cement, water, and an aggregate (usually gravel or sand)
|No preparation or mixing necessary
|Must mix water, cement, and aggregate in correct ratios; often requires cement mixer
|Ease of Use
|Easy to use
|5-10 minutes to set; fully hardens in a few hours
|24-48 hours to set; reaches optimal strength 25-28 days after installation
|Strong enough for small projects, but not for larger construction jobs
|Extremely strong and durable
|Around £6.40 per 20kg bag; approximately £691.20 per cubic metre
|£85 to £100 per cubic metre
Postcrete is perfect for fence posts, decking posts, gate posts, and rotary washing lines.
However, there are many projects for which concrete is a better choice.
These are mainly larger projects like commercial and residential buildings, dams, driveways, roads, foundations, fences, and bridges. Concrete is also used for culverts, sewers, and marine construction.
Generally, Postcrete is an excellent choice for small, quick projects, while concrete is better for larger jobs that require long-term strength and durability.
Postcrete is primarily made of sulphates, calcium aluminates, and calcium silicates. It also contains small amounts of lime, alkalis, and chlorides, as well as trace amounts of chromium compounds.
The aggregates for Postcrete include naturally-occurring sand mixed with combinations of various minerals like silica.
Concrete is made from three ingredients: cement, water, and an aggregate like gravel or sand.
Postcrete is 100% ready-to-use and doesn’t require mixing or any other form of preparation. This means you can save a lot of time on your project by using Postcrete!
Plus, because Postcrete comes pre-mixed, you can trust that the ingredients’ ratios are correct and don’t have to worry about potentially harming the product’s strength or durability.
The preparation process for concrete is much more complex and challenging.
It’s important to add the correct ratios of water, cement, and aggregate. Incorrect proportions of these ingredients can have major effects on concrete’s durability, workability, and overall strength.
In addition, you’ll likely need to rent or purchase a mixer if you’re making a large quantity of concrete. Although it’s possible to mix concrete in a bucket or on the floor, it can be difficult and messy.
Ease of Use
Postcrete is far easier to use than concrete, especially for DIYers.
The process for Postcrete essentially consists of pouring it into a post hole, adding water on top, and waiting a few minutes for it to set.
Meanwhile, concrete requires preparation and mixing and takes much longer to set than Postcrete.
One of Postcrete’s greatest advantages over concrete is its short setting time. Postcrete takes only five to ten minutes to set when used in suitable conditions. It fully hardens in just a few hours!
Consider a project like installing fence posts, for example. When using Postcrete, you’ll be able to install multiple fence posts very quickly, maintaining a consistent pace, rather than having to wait long periods of time for each post to fully set.
Concrete takes quite a while to set in comparison to Postcrete. It usually takes 24 to 48 hours to set.
In some situations, concrete takes seven days to fully harden. It reaches its full strength 25 to 28 days after installation.
Postcrete is not as strong as concrete, and it’s more likely to crack and break, especially around the edges.
You may find that if you try to drill near the edge of Postcrete that has fully set, you’ll likely create a crack that will result in a large chunk of the Postcrete breaking off completely.
Drilling into concrete can crack it, especially if you’re working with lighter-weight concrete, but it’s much less likely to crack than Postcrete.
Postcrete costs around £6.40 per 20kg bag, which comes out to about £0.32 per kilogram.
Keep in mind that you will generally need at least one bag of Postcrete per post, but the specific amount needed can vary depending on the size of the holes that need to be filled.
Concrete for domestic projects ranges from £85 to £100 per cubic metre.
In comparison, you would need approximately 108 bags of 20kg Postcrete to cover a cubic metre. This equals about £691.20 per cubic metre, nearly seven times as much as concrete.
Although concrete made in bulk tends to be much cheaper than Postcrete, you must also factor in the cost of a mixer and additional labour if you’re hiring someone to help you with installation.
Postcrete Vs. Concrete: Final Thoughts
In general, Postcrete is ideal for small projects, and concrete is best for large applications that require longevity and maximum strength.
However, Postcrete is easier to use as it doesn’t require mixing and sets in just five to ten minutes. In comparison, concrete needs to be mixed with perfect ingredient ratios and takes up to 48 hours to set.
Concrete is cheaper than Postcrete when purchased in bulk, but you may need to pay extra for labour or to rent or buy a concrete mixer.