Earth Loaves

This technique is a very simple earth building method broughtto Europe bya missionary who learned it in East Africa.The German school of agriculture at Dünne further developed the method during the 1920s, and since 1949 about 350 buildings have been constructed in Germany using this technique. 'Loaves' are formed by hand from well-mixed earth containinga high percentage of clay (Figure13.27).These clay loaves measure about12 x 12 x 25 cm.

The walls are built by laying the loaves on top of each other as in normal bricklaying, as soon as they have been kneaded, at a rate of four courses each day.They are reinforced with sticks every third course and at every course in the corners. After four to six weeks drying time the wall is strong enough to take the roof.The roof is often put up provisionally beforehand to protect the walls against rain during the drying period. The earth loaf technique can also be used for internal walls, with or without a loadbear-ingfunction.

The manor house of Skinnarbol in south east Norway from the early 19th century is built in the cob technique. Source: Rolf Jacobsen.

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The manor house of Skinnarbol in south east Norway from the early 19th century is built in the cob technique. Source: Rolf Jacobsen.

EXTENDED STRAND TECHNIQUE

This method has been recently developed by theTechnical High School in Kassel,Ger-many, and is a development ofthe earth loaftechnique. Inthiscasethere is not as much clay in the mix, as shrinkage would cause a problem, but the amount of clay must be enough to give the mix a certain elasticity.

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The earth loaf technique. Source: Verein Heimstätte, Dünne.

The earth is put in an extruding machine used for bricks (see Figure 8.6), compressed, and then extruded in tubes of 8-16 cm in diameter. The capacity of the machine is 1.5 m of tube per minute, and the length is unlimited. The material is so well compressed from thestart that it can be combined and built without waitingfor the lower layer to dryout.Witha mobile extrudingmachine ahouse canbe built inafewdays in the same way that a vase of clay is made with long clay 'sausages'. Mortar is not necessary, but the walls must be rendered afterwards. This technique is still at an early stage of development.

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