What are the Disadvantages of Compressed Earth Blocks?

Compressed earth blocks (CEBs) have several disadvantages, including susceptibility to moisture, a relatively brittle nature, and a lower resistance to fire than alternatives like concrete. Nevertheless, many businesses will still use compressed stabilized earth blocks for their residential or commercial projects — our team at Lontto is here to better inform you.

While earth bricks can be a great option, you should understand the limitations that these natural materials have. We'll be taking an in-depth look at the disadvantages of compressed blocks, when to use them, and the types of advantages you can expect from including CEB blocks over traditional cement.

Compressed Earth Blocks Disadvantages Explained

We’ve outlined the key disadvantages of CEBs in the table below:

We'll be taking an in-depth look at the disadvantages that earth pressed blocks have, using academic research and insights from construction companies. If you're debating between choosing concrete blocks and compression earth blocks, you'll want to take a look at these disadvantages before you make your final decision.

Material and Production Challenges

Compressed earth blocks (CEBs) often face several material and production challenges that limit how much you can manufacture and the quality of the earth building they're used for. Here are some of the most notable challenges you may encounter when using compressed earth bricks as a construction material:

• Soil Composition and Quality: When sourcing local materials for earth block construction, finding soil that has the right composition is incredibly important. Ideally, the soil should be made from around 80% sand, 10% silt, and 10% clay. This can vary from one construction site to another, making it difficult to standardize earth block production.
• Stabilization Requirements: When making CEBs, you'll often find that their durability and strength need to be improved using stabilizers. Cement or lime is added at a ratio of 10:90, which increases the costs of your production process and increases the carbon emission of your project.
• Machinery Costs: Most bricks and blocks require specialized machinery that can be seen as a barrier to entry for many companies. Machinery to make CEBs often requires higher costs and investment from businesses. However, this can be averted by being smart with your compressed earth block machine.
• Curing Time: Once compressed earth blocks are made, they need at least 28 days of curing to achieve the compressive strength they need to be used in construction projects.

The variable materials and production are some of the foremost properties of compressed stabilized earth blocks that make them a disadvantageous option for your project. These variables will affect your project from acquiring the materials to the curing time required to make earth blocks ready for the construction industry.

Structural Limitations

While compressed earth blocks are often used because of their sustainability compared to concrete bricks, there are certain structural limitations for CEBs that limit the type of structure you can build. According to a PubMed Central study from 2021, the compressive strength of CEBs is between 2.0 and 5.0 MPa — far lower than other concrete masonry units or fire bricks.

As a result, buildings made from compressed earth blocks can often exhibit low tensile strength, low flexural strength, and are limited in height. However, this can be partially negated by incorporating fibers as reinforcement during construction, with a fiber content above 0.6% leading to deflection-hardening behavior.

Durability Concerns

There are also several durability concerns regarding materials like compressed earth blocks, namely their susceptibility to moisture and exposure to high thermal conditions after curing. Construction projects in regions with drastic wet and dry seasons will find that the durability of CEBs or compressed stabilized earth blocks (CSEB) will be severely affected.

To combat this, compressed earth blocks can be reinforced with lime or concrete to withstand weather conditions and high temperatures. This was supported in a 2022 study by the Built Environment, which found that CEBs stabilized with lime showed an increase in compressive strength by up to 49% after exposure to 12 wetting-drying cycles.

Labor Issues

Labor is another disadvantage that can disincentivize your company from using CEBs for your next project. The production of CEBs is extremely labor-intensive, often requiring at least a dozen workers to dig, mix, press, and cure to facilitate the production of earth blocks for a project. This can also lead to almost half of your costs going towards labor, which could match the transportation costs you save.

The staff you hire should also be skilled enough that you don't have to make as many blocks, which will cost you more in the long run.

Environmental Impact

There's no doubt that you save significantly on your carbon footprint when using compressed earth blocks over concrete bricks, but this won’t be completely environmentally neutral. To gain the strength to be used to construct a natural building, the compressed blocks need to be mixed with anywhere between 4 and 10% Portland cement and constructed with mortar to keep it in place (unless you are using bricks that interlock).

Soil erosion is a particular environmental impact you also need to consider when using earth blocks in sustainable construction projects. The use of earth blocks requires the extraction of soil from local land, which can disrupt the local wildlife and ecology of the region.

Societal Perception

In many places, compressed earth blocks are often only associated with low-cost housing, which may lead you to difficulties when suggesting CEBs for upmarket or high-end residential and commercial buildings when compared to traditional clay bricks. In places like Burkina Faso, compressed blocks are seen akin to adobe blocks — a low-cost mud brick.

Potentially because of this perception, you will have difficulties not only finding projects that are open to using CEBs, but also hiring individuals who know how to work with the blocks.

Are Compressed Earth Blocks Worth Using?

Yes, compressed earth blocks are worth using in the construction of a green building or other sustainability project. While several disadvantages prohibit your potential to build with CEBs, they certainly have their place for both low- and high-budget construction work.

CEBs: Advantages vs. Disadvantages

What are the Advantages of Compressed Earth Blocks?

Here is a more in-depth look at the advantages of compressed earth blocks:

• Environmental Benefits: CEBs are made from natural materials and require significantly less energy to produce compared to traditional bricks and concrete blocks. CEBs only generate 22 kg of CO2 per ton, compared to 200 kg for conventional bricks.
• Energy Efficiency: Buildings constructed with CEBs have excellent thermal mass, which helps maintain stable indoor temperatures and reduces the need for artificial heating and cooling. They are susceptible to high temperatures; however, this can be negated with the right ratio cement or lime.
• Affordability: The primary material for CEBs is often locally available soil, reducing transportation costs and making them a cost-effective option in many regions for rammed earth walls or pavers.

When looking to choose compressed earth blocks for your next projects, it's always important to note both the advantages and disadvantages.

One less decision you have to make around using natural building materials for your next project is which block-making machine you need. Lontto offers you the leading technology in CEB block-making, all at a reasonable price. Get machine pricing for your project today with the click of a button.

Disadvantages of Compressed Earth Blocks FAQs

Are compressed earth blocks waterproof?

No, compressed earth blocks or CEBs are not inherently waterproof. Their water resistance largely depends on the use of stabilizers such as Portland cement or lime, which are mixed with the soil to enhance the blocks' ability to withstand moisture.

How thick are compressed earth blocks?

Compressed earth blocks are usually 3.5 inches (90 mm) thick. However, they can range in thickness depending on the standardized size your block-making machine creates. These can be anywhere from 3 to 4 inches (75 to 100 mm) thick.

What is the difference between rammed earth blocks and earth blocks?

The main difference between rammed earth blocks and earth blocks is how they are constructed. Earth blocks, or CEBs, are made individually while rammed earth blocks are compacted into formwork for their construction.

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