Rammed Earth Construction – Process & Strengths
Rammed earth constructions are a tried and true method of architectural work throughout history. The process is used in cultures across the globe and has just as many names. It is an elemental methodology for building, by its very nature borrowing from the land, harnessing strength and shaping purpose to create a dwelling that is a reflection of a singular place on Earth.
Taipa in Portuguese, tapia in Spanish, pisé (de terre) in French, and hāngtǔ in Chinese, rammed earth has been done on every continent on Earth (aside from Antarctica of course). It’s an ancient yet timeless traditional means of building foundations and walls which is experiencing a contemporary rediscovery. Rammed earth construction uses the readily available earth, chalk, lime, or gravel of a location to create the walls and foundations of a dwelling.
How Rammed Earth Constructions are Built
First, a formwork is built to the dimensions of the desired wall. The formwork, a temporary mold for the earth to fill, is simple. Typically walls of plywood or similar are held tight to give the rammed earth its, well, form. The earth is then dug up and filled into the formwork, usually in a thickness of four to ten inches at a time. The earth is compacted (or rammed if you prefer) to half that size, pushing the material together creating a strong, dense structure. This process is repeated until the entirety of the formwork has been filled in and hardened.
The section of the wall is completed and the formwork can be moved for the next portion. In the past the sections of damp earth would be rammed together using long poles, making for incredibly labor-intensive work though now this is typically done through pneumatic tampers. Modern rammed earth structures will be built on top of a conventional footing or concrete slab base. They might not be the ancient techniques of rammed earth, but they will help ensure the structure is sturdy and stays put for a long time to come.
When the formwork is removed, the wall is perfect for additional design work, such as wire brushing to create textures or patterns. After an hour or so, depending, the wall won’t be workable any longer and will stand resolute.
Rammed earth is a sustainable form of architecture, using local materials and resources for construction. Since the materials are readily on hand, just a few feet below our feet, they have low embodied energy (the impact of greenhouse gas emissions on the creation of the material) whereas other materials such as steel or reinforced concrete use an incredible amount of energy to create and build with them.
The formwork used throughout construction is also removable and reusable drastically reducing the amount of needed lumber to complete construction.
One significant benefit of rammed earth is its ability to store heat (or thermal mass). Like concrete or brick, rammed earth absorbs heat during the day and releases it overnight. This natural feature of the material moderates the daily temperature changes, reducing the need for heating and air conditioning. Insulation can also be applied to it in colder climates to further ensure comfort if needed.
Rammed earth walls are simple, strong surfaces that have weight and presence to them. They are warm, their surface a reflection of the surrounding earth itself creating a structure that is a part of the landscape itself. Philosophically, the use of traditional means like rammed earth construction and other vernacular architecture gives the structure a true sense of place. It grants the people who dwell there harmony with the landscape, as their lives are a part of the natural world, not closed off and in spite of it.
Rammed earth is also a tried, true, and modest construction method. While it might be physically demanding, only one person on the job needs to know how it works to be able to see a project from conception to completion and ensure the quality of the walls. Beyond that, everyone else on the job can be semi-skilled and still create a beautiful, strong structure.
Rammed earth constructions are a kind of vernacular architecture that can be realized anywhere on the globe, let alone America. While the structure is sturdy, the way the material is moved from the local earth to a nearby structure ensures that the process can be done in any climate including temperate, wet, semiarid desert, montane, and tropical environs.
Building with rammed earth is just one style and approach to creating homes that are as much a part of the landscape as they are an escape from the dizzying modern-day, where moments can expand into memory. D U S T continues to pursue that goal, to build a tangible place from the dreamscape, and give our clients something truly unique. Have more questions? Reach out and let’s keep the dialogue going.