Homeowners as well as builders and developers are always looking for new techniques that can help create more eco-friendly, sustainable homes. However, it is one of the oldest existing building techniques that provides one of the most sustainable solutions in the current day.
A building technique called ‘rammed earth’ has been around since ancient times, with plenty of evidence dating back to as long ago as 202 BC – AD 220. It places emphasis on using natural, unaltered materials that are commonly available. These include earth, chalk, lime and gravel.
During the building process, an additive such as cement or asphalt is used in conjunction with the earth to bind the material together. This material is then surrounded by a frame made of wood or steel, before being rammed repeatedly until the frame is filled with the material.
In the past, a long pole would have been used to laboriously ram the material into place, possibly using animal blood as an additive. However, building effective rammed earth structures is much easier today with pneumatic solutions in place for ramming material.
When a wall, floor or foundation has been fully rammed, the resulting material will be so solid that the frame can be removed without affecting the structure. The material should be left to cure for at least an hour while the ‘compressive strength’ increases further.
Why use rammed earth for sustainable building?
A construction process heavily reliant on naturally-occurring materials, rammed earth produces a pleasant and natural look that also does a great job regulating temperatures.
There is not too much limitation on where rammed earth can be used in construction. Currently, there are rammed earth structures on every continent except Antarctica. This goes to show how it can withstand different climates for thousands of years. The only real prerequisite for rammed earth structures is the availability of suitable surface soil.
Since the material is often strengthened with an inorganic additive, it is highly resistant to mold growth or natural decay. This means that these structures can survive for hundreds or thousands of years, meaning that you will not have to use energy to replace them anytime soon!
Rammed earth structures can even prosper in areas of seismic activity, since they can be fortified with rebars.
Returning to the previous point about temperature regulation – rammed earth naturally conducts heat during the day and releases it at night. Homes made with this material might see less need for energy-greedy solutions like air conditioning or fans because the rammed earth structures will do a great job of keeping the home at a comfortable temperature.
Another benefit of rammed earth is the fact that the frameworks can be reused after creating one structure. Once ready, the wooden frame gets removed from the rammed materials and can be used again.
One issue to bear in mind with this construction technique is the transport of cement when used as an additive. If building structures with rammed earth far away from a cement supplier, the transport of cement over long distances can add to the carbon footprint of this activity.
