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Rammed Earth is a building technique, dating back nearly 10 000 years, where locally available building resources such as soil, gravel, water and lime is mixed together and then tampered into shape using formwork to form the walls.

This building technique has seen a revival around the world recently as people seek more Sustainable building materials, and Natural building methods. Now Available in South Africa!!

InSynch's Rammed Earth walls conform to local building codes and to NHBRC requirements, making Rammed Earth the only form of natural building that qualifies for bank finance (bonds).

• InSynch's Rammed Earth Services:
• Complete Rammed Earth Construction (as Main Contractor or Sub-Contractor)
• Consulting
• Rammed Earth Engineering (Structural & Soil Mix Specification)
• Guidance & Best-Practice (Class 1, Class 2 and Class 3 Rammed Earth)
• Training
• On-Site Skills Transfer and Facilitation

Also See: Other Natural Construction by InSynch..

See: a Collection of Rammed Earth Projects from around the world and by InSynch:    Click Here!

Contact InSynch Today to enquire about implementing the most popular form of natural building in your project.

Rammed Earth also known as Pisé (French) is a building technique, dating back nearly 10 000 years, where locally available building resources such as soil, gravel, water and lime is mixed together in the correct proportions and then rammed or tampered into shape using formwork to form the walls.

This building technique has seen a revival around the world recently as people seek more sustainable building materials, and natural building methods.

Rammed earth is suitable to all climatic areas and regions and can be used in many styles of architecture from small informal buildings to community/social establishments, to up-market luxury mansions such as the ‘Meteor Vineyards’ by Cutler Anderson Architects, in California, the   ‘Vineyard Residence’ by John Wardle Architects in Australia, the ‘Palmer-Rose House’ by Rick Joy Architects in Arizona, the ‘Nk’Mip Desert Interpretive Centre’ in British Columbia, Canada, and the ‘Low Compound’ by Jones Studio also in Arizona USA.

Rammed Earth walls are relatively simple to construct, fire proof, thermally sound, very strong and durable. 

The History of Rammed Earth

Of the most common natural building techniques used today, rammed earth probably has a past that is most deeply rooted in terms of its history and proven pedigree.

Excavations in China have uncovered rammed earth construction dating from the seventh century BC. The Great Wall of China which began more than 5000 years ago is made from stone and rammed earth. To this day it remains one of the largest construction projects ever undertaking, and as we all know, most of it is still in use today. An unbroken tradition of natural building survives in many parts of the world, particularly in Africa, China and the Middle East. In these areas the scarcity of trees and precipitation and the abundance of soil and available and mostly cheap labour, natural construction and especially rammed earth are well suited. In North Africa, from the time of the pharaohs, to the present Egypt, the people of the desert have constructed their homes and villages from adobe, cob and rammed earth. In the Atlas Mountains, near Marrakech, the local tribesmen still today build rammed earth dwellings exactly as their forefathers have done for a multitude of generations. In Yemen rammed earth and natural buildings, still in use today rise up several stories.

Recently rammed earth was rediscovered by designers, builders and architects in the spirit of an ecological reawakening of recent times, due to the earth’s dwindling natural resources, the rise of oil prices, the increasing threat of global warming and the improving awareness of sustainability amongst the public at large. The rammed earth revolution in Australia was jump started in 1976 by one or two individuals, subsequent to that thousands of buildings have been crafted and hundreds of companies have discovered the benefits and beauty of rammed earth. This modern renaissance of rammed earth has also had resurgence in other parts of the world, such as the USA, New Zealand, France, England, Wales, Spain, Germany, Canada, and now South Africa.

The Basics of Rammed Earth

The rammed earth process begins with the soil selection. Traditionally and if possible today, the soil is gathered from site. The soil should consist of an appropriate mixture of sand, gravel, and clay and if the clay content is low or misunderstood by the structural engineer, cement or lime can be used as a binder (stabiliser). The soil is slightly moistened and compacted into monolithic walls between some sort of formwork that will govern the style and finish of the walls.

Modern rammed earth construction often use a stabiliser to ensure the load bearing and structural integrity complies with the rigorous modern building standards and also to ensure the walls are weather resistant. The most common stabilisers used are cement and lime. In keeping with the traditions of rammed earth the stabiliser content can be seen as negligible.

The most common stabilisers in Australia are: for rammed earth 6% cement; for adobes 3% bitumen; for pressed earth bricks 8% cement; for poured earth 12% cement.

The tampering process is important in the finish and structural integrity of the rammed earth wall, and can be either hand rammed with specialist rammed earth hand-tamperers or pneumatic rammers may be employed that offer a high and consistent vibrational activity and a higher output. To date, the pneumatic rammer has been difficult to source in SA and would be expensive to run and manage on site. With SA’s abundance of available labour, hand tampering makes sense as a valuable skill can be easily transferred, offering employment and skills development.

In modern variations of the method, rammed earth walls are constructed on top of conventional footings and foundation walls at a width suitable for rammed earth, usually around 300mm thick.

Sophisticated formwork and formwork building skills need to be employed when windows, doors and other building detail needs to be incorporated into the walls. Often, the join lines between formwork panels and clamp holes are left visible and to a varying degree, the complementary tolerances for rammed earth construction and the imperfections of finished rammed earth.. add to the beauty, uniqueness, texture and naturalness of the overall look and feel of rammed earth as a finished product.  Nothing else in the world of modern construction can quite compete.

Fit For Purpose

Increasingly we are seeing more and more architects and designers using rammed earth as a modern material that is durable, adaptable, environmental, beautiful and structural. An emergence of rammed earth is happening in South Africa for these same reasons.

The compression strength of rammed earth can be up to 4.3 MPa (620 psi). This is less than that of a similar thickness of concrete, but more than strong enough for use in multi-storey domestic buildings. Compressive strengths of 10MPa and more can be achieved by adding additional binder (cement or lime) as per engineer specification. However, research and international building codes for rammed deem a compressive strength of between 1,5 N/mm2 to 3.0 N/mm2 for walls of height 3.0m to 6.0m at a minimum age of 7 days to satisfy.

Rammed earth has been used around the world in a wide range of climatic conditions, from wet northern Europe to dry regions in Africa. Soil is a widely available, low cost and a sustainable resource, and utilizing it in construction has minimal environmental impact. This makes rammed earth construction highly affordable and viable for low-income builders as well as high-end projects. Unskilled labour can do most of the necessary work, and today more than 30 percent of the world's population uses earth as a building material.

Rammed earth can effectively control humidity where walls containing clay are exposed to an internal space. Humidity is held between 40% and 60% which is the ideal humidity range for asthma sufferers and the storage of susceptible items, such as books.

Rammed earth can contribute to the overall energy-efficiency of the building. The thickness, density and thermal conductivity of rammed earth makes it a suitable material for passive solar heating. Warming energy takes about 10 hours to work its way through a 300mm thick wall.

The material mass and clay content of rammed earth allows the building to "breathe" more than concrete structures, avoiding condensation issues without significant heat loss.

Rammed earth is suitable for complete home or commercial building construction used in conjunction with most conventional building products, such as flooring, roofing and finishing materials and certainly very well suited for decorative, feature type walls which can be admired as an integrated work of art, setting any building or stand-alone structure apart.   From homes, to religious, cultural, governmental structures, Rammed Earth has emerged as the most popular natural building technique in contemporary architecture culture.

Benefits and Challenges of Rammed Earth

One of the great benefits of rammed earth is the excellent thermal mass provided. A rammed earth wall heats up slowly during the day from the sun’s rays and radiates this heat back out during the night. Earth walls also provide good sound insulation as an added benefit. The downside to the thermal qualities of an earth wall is that they make for poor insulation and so in colder climates extra insulation is often required or a hybrid of conventional and/or natural building techniques can be used to fulfill the thermal properties that rammed earth lacks.

Earth walls have a low environmental impact and require much less embodied energy to create than most conventional building products such as concrete. The walls are very workable, and it is possible to hammer in a nail or screw into them. Any minor damage to the wall can be patched by using the same mixture of earth to give an almost undetectable fix.

Rammed Earth walls are:

1. ·Sustainable (Natural, low carbon footprint and can be easily reconstituted back into the environment after demolishing).
2. ·Load Bearing.
3. ·Conventional in shape.
4. ·Non-Toxic
5. ·Excellent Thermal Mass
6. ·Fire Proof
7. ·Attractive
8. ·Do not need plastering or painting.
9. ·Unique & individual finish (no two rammed earth walls will ever look the same).
10. ·Can be cost effective.
11. ·Breath & Can Control Humidity
12. ·Highly Decorative
13. ·Natural

Environmental Aspects & Sustainability

As rammed earth structures use locally available materials, they typically have low embodied energy and generate very little waste. The soils used are typically subsoil’s with a clay content of between 5% and 25%.

Often, the soil removed in the building process in order to prepare the building foundation can be used, further reducing cost and energy used for transportation.