Hempcrete vs. Concrete: Which to Choose?

Hempcrete vs. Concrete: Which to Choose?

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If you are planning on building any sort of structure, and you need it to be solid, there are some options you have at your disposal. Concrete is a very commonly used material, although hempcrete is also rising in popularity.

With that being said, there are some huge differences between concrete and hempcrete that you need to know about. Let’s figure out what both concrete and hempcrete are, what makes them similar and different, and which one you should use for certain building applications.

Hempcrete and Concrete: The Basics

Before we talk about the similarities and differences between hempcrete and concrete, let’s first figure out what they both are.

What Is Hempcrete?

First, we have hempcrete, which is becoming an extremely popular building material. Although it has not really replaced concrete as a building material, due to a variety of reasons, it is quickly becoming more popular. One of the reasons for this is that hempcrete is very eco-friendly.

Hempcrete is a composite building material made out of a bio fiber, which in this case is hemp hurd or hemp shiv, as well as a binder, which is lime. When the lime is mixed with water it creates a chemical reaction that causes the hemp particles to bind together.

When the binder has set and cured, and the water has dried out of the mixture, the result is hempcrete. Keep in mind that with this substance, the binder is not designed to fill all of the voids in between the hemp particles. Rather, it’s designed to coat the hemp particles so that they can stick together.

Therefore, there is a lot of void space in hempcrete. Hempcrete is often used as wall, roof, and slab insulation. This material is also often used to make prefabricated panels or even structural blocks for exterior walls.

What Is Concrete?

We then have concrete, which is a composite building material that is composed of both coarse and fine aggregates that are bonded together using fluid cement, usually Portland cement. Concrete usually also contains a great deal of sand.

When water is mixed with the concrete mixture, the Portland cement will react chemically with the water and will start to harden and cure. The result is an extremely hard and dense building material. The binder in cement does actually bind all of the materials together, and it does in fact fill all of the voids, which is why it is so dense.

Concrete is an extremely popular building material, especially because of its structural integrity. It can be used to make driveways, walls, foundations, and even for large-scale building applications, such as making skyscrapers and tall buildings.

Similarities of Hempcrete and Concrete

Now that we know what both hempcrete and concrete are, let’s figure out what makes them similar.

1. They Both React with Water

One basic similarity is that both hempcrete and concrete have binders in them that react with water, and will then harden and cure. The binders used in both of these building materials are different, but the fact remains the same. Water causes a chemical reaction which then causes them to harden into a very hard and strong material.

2. The Application Process is Similar

The application process of both of these materials is also quite similar. Both need to be mixed together and then poured into a mold or frame, and allowed to dry and harden.

3. Fireproof

Another similarity shared by both hempcrete and concrete is that they are fireproof. Hempcrete can withstand direct fire for over two hours before it ignites. So, although it may not be 100% fireproof over the span of several hours, it is challenging to ignite. Concrete is also highly resistant to fire, as it can be exposed to direct flame for up to four hours before igniting.

4. They’re Both Waterproof

The other similarity that both concrete and hempcrete share is that they are waterproof. Now, in terms of waterproof longevity, one may not last as long as the other.

However, both are totally waterproof, especially for the first few years after building. They are therefore often used for exterior projects, as they will not allow water to penetrate.

Differences Between Hempcrete and Concrete

Now that we know what makes concrete and hempcrete similar, let’s figure out what makes them different.

1. Strength

One of the major differences here is that concrete is much stronger than hempcrete. Commercial concrete has a compressive strength of 3000 PSI or higher. On the other hand, hempcrete has a compressive strength of just over 500 PSI.

This means that hempcrete is less than one-fifth as strong as concrete. Because of this, hempcrete is not ideal for large-scale building applications that need to be structural, such as for large buildings.

2. Longevity

Although this is really yet to be seen, as it takes time to determine, it’s safe to assume that hempcrete will last much longer than concrete. Concrete is set to last for about 100 years when properly applied and cared for. Hempcrete, on the other hand, based on all current research, should last for several hundred years.

3. Thermal Insulation

Hempcrete is also a much better insulator than concrete. Due to all of the voids inside hempcrete, and due to the structure of the materials, it creates a much better air barrier. Hempcrete is therefore a much more popular insulator than concrete.

4. Eco-Friendliness, Sustainability, and Toxicity

The simple fact of the matter is that concrete is not really sustainable, eco-friendly, or non-toxic. It’s actually a rather dangerous building material. Hempcrete on the other hand is completely eco-friendly, sustainable, and non-toxic.

5. Fireproofing

While both are fireproof, concrete is about twice as fireproof as hempcrete.

6. Composition

Of course, these two things are made with completely different materials. Hempcrete is made out of hemp and lime, whereas concrete is made out of aggregate, sand, and cement.

7. Voids and Weight

Concrete is much heavier and denser than hempcrete and doesn’t have nearly as many voids as hempcrete.

Can Hempcrete Replace Concrete?

Due to the fact that hempcrete has less than one-fifth of the strength of concrete, it cannot replace it. You cannot use hempcrete for large-scale building applications that have to be structural and weight-bearing.

Hempcrete vs. Concrete: Which of the Two Should You Use?

If you want to build anything structural in nature, whether a wall, a foundation, a driveway, or even a skyscraper, then it is concrete that you need. However, if you are insulating your home or building exterior panels, then hempcrete can be a great alternative.

Summary

You should now know all of the differences between hempcrete and concrete to make an informed decision between the two.

How Does Concrete Compare with Other Materials?

Below, you can find articles that compare concrete with: