Rammed earth construction is a technique used for building foundations, floors, and walls while only using natural raw materials. This ancient approach offers a sustainable building method that features chalk, lime, gravel, or compressed soil. Edifices formed from rammed earth are found on every continent except Antarctica. It works well in a range of environments, including tropical, desert, and wetland biomes.
Making rammed earth requires the compaction of a damp mixture of soil that has suitable proportions of gravel, clay, and stabilizer. You can put it into any formwork to create the desired structure.
After a wall is completed, it will be sufficiently strong enough to stand on its own. Its compressive strength continues to grow as the structure dries. Cement-stabilized rammed earth must cure for a minimum of 28 days.
Modern rammed earth structures sit on top of a constructed footing or a reinforced concrete slab.
If you are looking for a sustainable way to build a home without a significant expense, then the advantages and disadvantages of round earth are worth taking under consideration.
List of the Advantages of Rammed Earth
1. It provides excellent insulating options for off-grid living.
If you want to start homesteading and live off of the grid, then rammed earth buildings are an excellent choice for energy retention. You gain the benefits of an environmentally friendly construction material while receiving high levels of insulative qualities simultaneously. The thick walls that builders create using soil and clay can retain heat during the day, and then slowly release it at night.
This advantage will also retain heat inside the structure during colder months to prevent extreme interior temperature changes.
2. Anyone can create a rammed earth structure.
It doesn’t take much experience to create a rammed earth structure or building. As long as you know how to create forms and have the correct recipe for soil composition, then you have the tools needed to create a structure of almost any size. Although some materials on local properties may not be suitable for this constructive effort, shipping in the gravel or clay needed to finish a wall is not very expensive.
You can obtain the materials to create a rammed earth building almost anywhere.
3. Buildings made from rammed earth have more durability.
We know for a fact that the structures made from rammed earth can withstand the tests of time. These buildings have already proven to be sturdy for more than a century, and archaeological evidence suggests that some structures could last for more than 1,000 years. When you compare the cost of construction with other modern materials, this environmentally-friendly choice almost always comes out ahead.
4. If you do the work yourself, the cost of rammed earth can be almost nothing.
If you are willing to put in the work to create the rammed earth structures that you want, then the cost of this building material is negligible. It does require a significant amount of sweat equity to create the final outcome, but a DIY expert could quickly put together a home for less than $40 per square foot – and perhaps significantly less. Much of this advantage is based on the idea that the materials for the work can be obtained on local properties.
5. It has a high fire-resistance rating.
Rammed earth structures receive a four-hour fire resistance rating from the CSIRO when contractors use today’s best practices and methods. That means you have more time to get out of the building if an emergency arises. You may also find that the structure of a house built with these materials may have a lower reconstruction expense if something unexpected happens to it. You can still treat the exterior as you would with any other building material, which means you have lower costs without sacrificing the flexibility you might need.
6. Rammed earth offers a high level of moisture resistance.
If you live in a geographic region that sees a significant amount of precipitation every year, then this building option can provide a superior level of moisture resistance. Although you need to prevent continued exposure to water at the bottom and top of each wall as you would with clay brick, most soil compositions using the rammed earth technique don’t require additional waterproofing.
7. The nature of rammed earth is that it is non-toxic.
Because you are only using natural materials when building a structure with rammed earth, you don’t need to worry about any toxic substances being part of the manufacturing process. You even have the option to create natural forms so that you can avoid any potential chemical exposure from concrete or wood surfaces. This benefit is one of the primary reasons why families are now considering this environmentally friendly solution over some of the other building methods that are available today.
8. The material is useful for soundproofing.
Rammed earth walls are naturally soundproofed because of their density. That makes this material well-suited for areas that encounter a lot of noise pollution. If you build multiple interior walls using this product, then the outside world may not have a chance to reach your ears. When you combine this trade with double pane windows and other soundproofing technologies, it is possible to create a quiet indoor environment that is unlike any other.
9. It provides a high level of versatility.
Many architects find it easy to style homes made with rammed earth because of the natural color and texture variations found in the building materials. That means you can create something stunningly beautiful while also supporting the environment and reducing your carbon footprint.
10. Rammed earth offers a high level of pest protection.
If you have problems with termites on your property, then this building material can provide you with a significant amount of protection. There are no cavities in the walls where pests can reside or find a way to your interior structures. Repainting, plastering, and wallpaper are not necessary because reinforcements are rarely needed for this material. Once it cures, it is virtually impenetrable to most pests.
You must still take care when working around your entryways and windows to ensure intruders are not able to get through those transition points.
List of the Disadvantages of Rammed Earth
1. The cost of rammed earth can get significantly high.
The cost benefits of rammed earth are possible only when you are sourcing local materials and doing all of the work by yourself. Once you start hiring laborers and contractors to obtain supplies, the expense of using this environmentally friendly material can quickly rise. The price per vertical square foot in some areas of the United States can be as high as $300. If the job you need to complete is complex, then this cost could potentially double.
There are undoubtedly ongoing benefits that can reduce the long-term expense of using this product, but that savings may take several years to make an appearance. You can expect the final cost to be up to 15% more than it would be for a conventional home.
2. It doesn’t provide long-term insulative benefits.
The materials that rammed earth processes use typically contain a high thermal mass. That means it is not a particularly good insulator. When there is a significant difference between the inside and outside temperatures, or the daytime and evening temperatures, then the slow release that this option creates can provide tremendous savings to your utility expenses. If it is poorly installed, then this product can radiate heat all night long during the summer and absorb what you produce at night in winter.
Even though it has excellent thermal mass and a low embodied energy, the insulative qualities are not high when you use this technique. Prolonged exposure to significant temperature differences can create an uncomfortable indoor living environment.
3. If you build from your property, then you’ll create holes in the ground.
The cast profile of a rammed earth structure can be particularly appealing for families or businesses that want to establish an off the grid presence. When you take the materials for this structure from land that you own, then it will become necessary to figure out what to do with the large holes that you create. The amount of soil, gravel, and clay that are necessary to create the correct ratio of compaction can severely pockmark the surface of the land.
4. You may need to pay for added insulation.
If you live in a colder climate and want to use rammed earth as your primary building material, then it is highly likely that you will need to add insulation to your building structure. One of the common ways to manage this disadvantage is to use foam that can be covered with concrete. When you solve this problem, then you often negate the benefit of reducing your potential exposure to toxic elements.
There is also the added cost of purchasing and installing the insulation to consider. That’s why you typically see structures made with rammed earth in warmer climates.
5. It is challenging to correct issues after a wall gets built.
Once a wall gets built using rammed earth as the building material, the final structure cannot be easily corrected if a mistake gets made. Unlike brick or stone, you cannot make changes as the wall becomes vertical because you are packing everything into a form. If there are air bubbles or problems with the quality of the materials, the issue may not get noticed until the curing process begins.
Although you can correct surface issues by smearing more of the soil composition along the surface of the wall, hidden faults may go unnoticed until it is too late to correct.
6. Rammed earth gets limited to low-rise buildings and square shapes.
Rammed earth usually requires a single-story construction method because of the strength profile of this product. As a wall becomes more vertical, it must have additional supports placed at the base of the wall to maintain stability. Because this building option doesn’t use modern tools or materials beyond the use of the original form, you can only achieve two stories for most structures using today’s best practices.
Most countries have building codes that contractors must follow when creating structures for residential or commercial purposes. Rammed earth buildings don’t always fall into these regulations, which means the quality of the craftsmanship may be questionable. This issue also dictates a square structure for most projects since round forms aren’t always available.
7. It may take more work to gain approval from insurers or bankers.
Rammed earth is considered to be an alternative building method in the United States. That means it may take more work to win the final approval for a completed project. Bankers and insurers might not know how to provide you with the correct level of coverage or lending assistance to turn your ideas into a reality.
The Southwest U.S. uses this method more frequently than any other region, so rammed earth is beginning to appear in some building codes. If you do not live in Arizona, New Mexico, or Colorado, then you may find it should be a challenge to obtain a construction loan, mortgage, or homeowners’ insurance.
8. It takes a long time to cure a rammed earth wall.
Rammed earth might look like it is finished once it comes out of the form, but most projects require about a month of curing before the structure is usable. That means your construction project will lose some valuable time while the walls start hardening. There are definite environmental advantages that are worth considering if you want a sustainable outcome, although it can be a significant time investment to achieve them. That’s why the length of the building project must come into consideration when using rammed earth as your primary material.
Rammed earth can effectively regulate humidity levels if clay-containing walls left unclad receive exposure to the internal space. Most properties see moisture levels in a range between 40% to 60%, which is the ideal level for people with asthma or other breathing issues. You can avoid problems with condensation because of this benefit, but it comes at the expense of a significant loss of heat.
If you want to use an environmentally friendly building material, then this option is one of the best ones that’s available in today’s market. It may cost more if you aren’t doing the work yourself, but the advantages can make that investment seem like it is worth the expense.
These rammed earth advantages and disadvantages may vary based on your geographic location and the quality of building materials used. It is an easy way to support sustainable living while enjoying the comforts of modern life.
Brandon Miller has a B.A. from the University of Texas at Austin. He is a seasoned writer who has written over one hundred articles, which have been read by over 500,000 people. If you have any comments or concerns about this blog post, then please contact the Green Garage team here.