Congress about “Construction in Earth and Clay”

By Kurt Rhyner  

 The German association about construction with earth and clay, “Dachverband-Lehm e.V.”, organized an international congress to celebrate its tenth anniversary. We decided to participate in order to become acquainted with the points of view of German practitioners and make contact with other people interested in the theme.

AdobesPresentations by people from various European countries provided a relatively positive overview. It appears that health aspects are the principle arguments among people today who decide to build with earth. The overriding preoccupations are electrosmog (the radiation waves emitted from cellular antennas), as well as the materials that contain harmful elements.

The discussion concerning the potential damage made by electro-smog more and more centers around the level of radiation permitted and the techniques to protect people, as it is generally accepted that such antennas do emit radiations that are harmful to the health of people. It has been demonstrated that clay walls absorb these radiations best. Other materials in the market allow them to pass or reflect them, while, to a great extent, earth absorbs them.

Many materials emit poisons such as "formaldehyde", a glutinizing agent used in sheets composed of wood, carpets and many other elements. We heard an interesting presentation about investigations concerning the capacity that clay has to neutralize the damaging elements and the possibilities to improve this through insertion of animal hair in the plaster. (info in

The presentations reveal that throughout Europe the earth has been on of the predominant construction materials throughout the centuries, and that still today in many regions of Europe there exist hundreds of thousands of buildings made of earth, many of which are hundreds of years old. However, there are few buildings that have been built entirely of earth, rather the great majority are wood skeletons filled in with earth. Applications of pure earth are usually with the "rammed earth" technology.

An impressive presentation by Jan Ruzicka of the Czech Republic focused upon a series of investigations about pressed bricks, where they have encountered that the pressure applied is the determining factor, while the addition of lime or cement contributes very little to achieving a strong resistance when compressed. This confirms the results obtained several years ago at CIDEM. In posterior discussions with the author (a young doctorate candidate) I suggested that he make a similar serious of tests, but testing the bricks while moist, as this is the condition that is most worrisome in the practice.

During the same presentation we viewed a simple building, constructed with pressed bricks without additions, that resisted the tremendous floods this past summer even though they were inundated. One sees the marks left by the waters at a level of two meters. (This email address is being protected from spambots. You need JavaScript enabled to view it.)

A major argument in Germany concerns the fact that earth walls and plasters are excellent absorbers of humidity, that is to say, they absorb humidity and reintegrate into the environment. This contributes to an agreeable internal climate, especially in cold regions, where people spend a great part of the time inside.

During the congress there were many bilateral conversations and I was able to learn much about the incipient new industry of clay construction in Germany. There are various material providers, and one buys the clay prepared in bags to be mixed onsite with sand. There are various qualities of mortar, interior plasters, and external plasters, although last-mentioned are not completely accepted. In the difficult climates of Germany, with great variations in environmental humidity and with periods of freezing, the requirements for external plasters are extreme, and the constructor has to provide an unconditional guarantee of two years and a partial guarantee for ten years.

There was also an interesting presentation about the adaptation of the plastering machines to apply clay plaster. Of course, in Germany it is rare that plastering is done by hand.

On the Sunday of the congress there was a visit to constructions in the region, and in some towns we could see quantities of well-maintained houses built of wood and earth. On a visit to a mine we were able to appreciate the simplicity of the installations to mill, mix and package the clays, as well as the production of pressed bricks (without additions of cement or lime).

September 2002   
You are here: Home Past editions October 2002 Congress about “Construction in Earth and Clay”


Orlando Espinosa
Civil Engineer
Spanish, Russian, some English.
Equipment development, MCR workshop installation, operative project implementation


Teja de MicroConcreto
MicroConcrete Roofing Tile machine
The tevi model TM5 may works with a 12V inverter or with solar panels or a car batery, by itself. A well trained, 2-people team, can produce up to 350 tiles per day
Read more ...