UGANDA, Kampala | Real Muloodi News | The use of rammed earth technology is not a new concept. Rammed earth is an ancient construction technique that dates back thousands of years. For example, the Great Wall Of China which is 2,700 years’ old was built with rammed earth. However, today this ancient rammed earth technique is being applied to beautiful modern architecture.
What is Rammed Earth?
Rammed earth is a technique for constructing foundations, floors, and walls using natural raw materials such as earth, chalk, lime, or gravel.
The soils are compacted and made into building blocks, where the soil is rammed into a box-shaped mold. Alternatively, rammed earth can also form whole walls in place, layer by layer.
In building up whole walls, two wooden planks separated by a spacer bolt are used for form, into which the earth is rammed in layers, until the desired height is reached.
For the ramming, Ironheaded rammers, roller-mounted forms, pneumatic rammers, and hydraulic, mass-production block presses have been used.
The soil used must be high in sand and low in clay, 70 percent and 30 percent being the usual proportions. Sometimes cement is also added as a stabiliser, as well as about 10 percent water in modern practice.
It is said to be the most durable of the earth-building forms, with rammed earth houses lasting over 1000+ years.
Suitable Climates for Rammed Earth
Typically, this technique works best in high humidity climates and with relatively moderate temperatures, like that of Uganda. In colder climates, rammed earth walls need additional insulators.
In locations with very high rainfall, they may need additional protection against rain, such as extended overhanging eaves to shelter the earth walls, and lifted on solid raised footings at least 225 mm above ground level.
Benefits of Rammed Earth
Well designed and built rammed earth homes are warm, dry and energy efficient. Rammed earth walls ‘breathe’ so they counteract humidity, and naturally maintain a stable internal temperature throughout the seasons.
Rammed earth homes are sustainable and environmentally friendly and non-toxic. Only a small amount of energy is needed to manufacture and construct the walls. Any left over earth from the building process can be safely spread on site.
Rammed earth homes are low maintenance. There is no need to finish rammed earth walls with plaster or paint, inside or out. In fact the bare walls are a beautiful feature that many people choose to leave exposed.
The solid nature of rammed earth walls means they offer excellent sound insulation. The solid walls also reduces pest problems, with no cavities or gaps for insects and vermin to enter. And because earth doesn’t burn, rammed earth homes are also very fire resistant.
Natural, Unique Beauty
Each rammed earth wall has a unique look with inherent beauty and character, which can be customised. A rammed earth home can be contemporary or rustic, and compliments the landscape wherever you build. Rammed earth also looks great with various other building materials, particularly natural timber and stone.
How Much Does Rammed Earth Cost?
The cost of rammed earth depends on a number of factors. Large quantities of windows and doors, lots of small sections of wall, and height wall height can all increase costs.
According to Andy Byrnes, president of the Construction Zone, a USA design-build firm in Phoenix, prices start at $75 (USh 267,500) per square foot and can rise well beyond that, depending on the height and complexity of the wall.
Rammed Earth in Uganda
Entebbe Children’s Surgical Hospital, situated along the shores of Lake Victoria in Entebbe, is marked by its rammed earth walls together with its monumental glass facades. In fact, it is one of the largest modern rammed earth projects in the world.
The new hospital was designed pro bono by Renzo Piano, one of the world’s leading architects. Italian fabrication firm, Zintek, also played a major role in the construction of the renzo piano-designed hospital.
The rammed earth wall is one of the ancient construction methods, and it is worth investing in today. Being an environmentally friendly, strong, and even aesthetic material, rammed earth has a lot of potential for the future.
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