We’ve all been there – you’d like to embark on your construction project with a preferred material in mind.
However, the elephant in the room is that you must learn the pros and cons of using that material. Take rammed earth construction, for example; will its pros outweigh its cons for your construction needs?
Construction projects are often associated with high costs. Consequently, you want to be sure that the material you choose meets your project’s structural and environmental requirements.
Although less popular than other building methods, rammed earth construction may be your ideal choice. You can decide whether it meets your needs by assessing its pros and cons.
In the rest of this article, I’ll discuss the pros and cons of rammed earth construction. From its cost to the best type of insulation to go with it, you’ll get everything you need to make an informed decision about your project.
But first, let’s chat about all things ‘rammed earth construction.’
1. It’s Highly Sustainable
The construction industry contributes 50 percent of global climate change. This is due to the use of conventional building materials like timber and concrete. Besides consuming a lot of energy, these materials contribute immensely to the waste in landfills and deforestation.
Shifting to sustainable building materials like rammed earth is the best way to mitigate the environmental impact of the construction industry.
Rammed earth uses natural materials that are readily available in most regions. This eliminates the need to transport materials using fossil fuels, contributing to global warming.
Moreover, rammed earth construction doesn’t consume energy because it only involves mixing aggregates and ramming them.
From a technical point of view, concrete has 635 kg of embodied carbon per cubic meter. On the other hand, rammed earth has an average of 48 kg of embodied carbon per cubic meter. This proves that rammed earth is suitable for reducing greenhouse gas emissions.
2. It Offers Excellent Heat Retention
The heat retention rate for any wall system is directly proportional to its thermal mass.
A wall with a high thermal mass will absorb and store heat from the sun. Then, when the temperature gets cold, especially in the morning, evening, and night, such a wall releases the stored heat to keep the room warm.
Rammed earth walls boast a higher thermal mass due to their high density of 1,540 kg/m3. The high density is attained by mixing and ramming clay, sand, gravel, and silt.
When a wall is constructed with rammed earth, it absorbs heat during the day and slowly releases it in the evening when temperatures drop. This eliminates the need for artificial heating, helping save energy and money.
3. Highly Fireproof
Rammed earth is highly fireproof thanks to its high density. In addition, denser walls prevent a fire from spreading more quickly.
This makes rammed earth suitable for building homes in regions prone to wildfires or other fire disasters.
4. It’s Highly Versatile
Architects find it easy to style rammed earth houses in different ways.
Rammed earth offers many design possibilities due to its flexibility and diversity in color, texture, and shape.
The high versatility means you can create something beautiful and unique.
5. Highly Durable
Rammed earth construction is your go-to technique if you want a long-lasting structure.
Rammed earth can last more than 1,000 years, making it an ideal selection for people who want to leave something behind for future generations.
The high durability of this material is based on its excellent resistance to fire and pests.
6. Low Maintenance
Unlike other construction materials, rammed earth doesn’t require regular ongoing maintenance.
Once rammed earth walls are in place, they don’t need painting or any other treatment to remain strong and beautiful for years.
The low maintenance requirement makes it an ideal choice for people who don’t have time to maintain their homes.
Once your structure is up, you can enjoy a carefree life for 10 to 20 years.
7. Highly Susceptible to Water Damage
Rammed earth is made from natural materials – sand, clay, silt, and gravel.
Although the materials are highly durable and strong, they are not waterproof and, as a result, become weak if exposed to water for a long time. This can cause structural damage to your rammed earth wall.
Since rammed earth is not waterproof, you must take steps to protect it from water. One way to do that is by building efficient drainage systems.
Alternatively, waterproof the walls using a water-based silicone admixture like plasticure.
8. It’s Costly
Contrary to popular belief, rammed earth construction is costly, even more than its concrete counterpart.
Rammed earth construction can only be cheap if you’re sourcing the materials locally and doing the work yourself. Otherwise, prepare to dig deeper into your pockets.
The process requires substantial labor and skilled professionals to mix, ram, and shape the aggregates into a durable wall.
The fact that soil is everywhere doesn’t mean you can get the best soil for rammed earth construction anywhere. Sometimes, you may have to source the soil from a different site. In this case, you’ll incur transportation costs.
To put the cost issue into perspective, building with concrete costs between $4 and $8 per square foot, depending on factors like labor and concrete thickness.
On the other hand, rammed earth construction costs between $50 and $225 per square foot.
Although rammed earth construction is costly, its long-lasting benefits and sustainability make it worth the price.
9. It’s Time-Consuming
Constructing a rammed earth wall takes time, so don’t expect to finish building your home overnight.
You need to prepare and mix the soil with an appropriate amount of water for better compaction. You must also build shuttering to form the wall and ram the soil in layers.
After putting up the wall, you must wait for it to cure before finishing.
The slow process means you must wait a few weeks or months before the structure is ready for use.
However, the time-consuming nature of this method ensures you get a quality structure with long-lasting benefits.
It’s worth mentioning that rammed earth is prone to cracks during the curing process. However, the cracks are not a big deal since they’re non-structural.
10. Poor Insulation
As already mentioned, rammed earth has a high thermal mass.
High thermal mass is a double-edged sword; on the one hand, it provides excellent heat retention, but on the other hand, it lowers a material’s insulating capacity.
The high thermal mass of rammed earth is the reason for its lower R-value of 0.4 per inch. A lower R-value means that the material has poor insulation.
Therefore, if you need a material that offers good insulation, consider other sustainable materials with higher R-values, like straw bale and cork.
If you must use rammed earth, consider insulating it with rigid foam-based insulation. This is especially important if you live in a place with large temperature fluctuations.
Failure to insulate your rammed earth walls exposes you to high energy costs due to the increased need for heating and cooling.
11. Lack of Building Codes
Natural construction methods like rammed earth are not considered conventional in some countries. Therefore, there are no specific standards and codes for these types of construction in such countries.
The lack of building codes makes getting building permits for rammed earth construction hard. Furthermore, getting insurance for rammed earth construction can be challenging, making it a risky investment.
In other countries, using rammed earth may be permitted under unconventional codes. In this case, you’ll have to hire a specialized engineer to help you meet the standards.
Therefore, if you want to use this method, it’s vital to first research the policies in your area before starting any construction work.
Final Thoughts On The Pros and Cons of Rammed Earth Construction
Rammed earth construction presents a unique set of pros and cons that must be considered before embarking on a building project.
It is highly sustainable, particularly if suitable materials can be obtained locally. It’s also very durable and fireproof.
However, it costs much more to build with than concrete, partly due to the time-consuming building process. There’s also a lack of building codes for rammed earth in some countries.
As with any construction method, weighing the benefits of rammed earth construction against its drawbacks is essential to determine if it fits your needs and goals.
Before using rammed earth for your project, you might wonder if it suits floors. Check out this article discussing whether you can use rammed earth for floors.