What is Rammed Earth Construction?

Rammed earth construction is a structural building method of compressing a sandy mixture into a hard sandstone-like material. Rammed earth walls resemble adobe construction. Both use soil mixed with waterproofing additives. Adobe, however, requires dry weather so that the bricks can harden (cure) enough to build walls.

In rainy parts of the world, builders developed "rammed earth" construction, which is more like building a sand castle with forms. A mixture of soil and cement is compacted into forms, and later, when the forms are removed, the solid earth walls remain. The compression of the earth material is more like building compressed earth blocks or CEBs, a process of squeezing out the air in a precise mixture of clay, sand, and lime.

Definition of Rammed Earth

"A material usually consisting of clay, sand, or other aggregate (such as sea shells) and water, which has been compressed and dried; used in building construction."— Dictionary of Architecture and Construction, Cyril M. Harris, ed., McGraw- Hill, 1975, p. 395

Other Names for Rammed Earth

This building process is an ancient method that has been practiced throughout the world for centuries. Rammed earth and forms of earth construction similar to rammed earth are also known as pisé, jacal, barjareque, and hāng tǔ.

Modern Rammed Earth Method

Rammed earth buildings are environmentally-friendly and water, fire, and termite resistant. It is naturally sound- and mold-resistant. Some modern-day designers also say that the thick earthen walls create a sense of solidity and security.

Canadian builder Meror Krayenhoff has modified the ancient practices of rammed earth, creating what he calls Stabilized Insulated Rammed Earth or SIREwall^®. "We use a little bit of cement—5-10 percent cement—and we use some steel reinforcing to make it strong against earthquakes. We put the soil in on either side of the foam [insulation] and compact it."

The price of a rammed earth wall is generally a bit more than poured concrete, but cost is dependent on location. Since a majority of the price tag is labor, the market price for installation fluctuates depending on where in the world you're building.

Learn More

• David Suzuki's The Nature of Things, Build Green episode, CBC TV, June 2007
• About the Sirewall System
• Steve Davis website, see photos of rammed earth buildings
• The Rammed Earth House by David Easton, 2007
• Earth Architecture by Ronald Rael, Princeton Architectural Press, 2010

Source

• Rammed Earth with David Suzuki, The Nature of Things, YouTube accessed July 21, 2014