‘Fachwerk’ building materials with history
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Since the early Stone Age period, clay, wood and straw belonged to the basic building materials in Central Europe. The building constructions and the roof consisted of wood, and clay was used for the structure of the walls, straw for the roof covering.
The oldest half-timbered houses in Germany date from the 14th century. While there are only a few buildings from this period, many houses have survived from the 18th and 19th centuries, small homes to big mansions.
Since the 15th century half-timbered houses were often built with masonry ground floors, so to speak as a foundation for the wooden upper floors. This had a decisive advantage: The wooden structure was protected against rising dampness.
The half-timbered construction method was granted a long life. Even castles, such as in Gießen and Coburg, were built in this way in the 16th and 17th century.
In the countryside, the framework was the prevailing method of construction even into the 19th century. In many cities, however, it was displaced over time by stone buildings, as they were considered more distinguished and less fire endangered.
Wood – a Support Function
Almost every region developed its own framework, but the basic concept was the same everywhere. The process and connection of the wood with each other always took place according to the system of scaffolding construction.
For this purpose, the craftsmen first erected a three-dimensional latticework of vertical uprights, as well as horizontally and diagonally clamped timber – so-called bars and struts.
The resulting spaces, the compartments, were then stabilized with wickerwork of thin branches and plastered with a mixture of straw and clay. Instead of the wickerwork, logs (split wood) or planks (thick boards) could be clamped in the compartments and spread with clay. Also fillings from broken up bricks were installed by the craftsmen.
However, this lightweight wall first gave stability to a wooden threshold, a wooden frame resting on the floor or a wall, in which all the posts were clamped. In this way, the medieval houses could now also grow in height: each floor was based on its own threshold, so was a self-contained unit. This meant that up to five stories could be stacked, each stabilized by the threshold.
Modern half-timbered houses, where only the scaffolding stands. The framework of the half-timbered building is made of wood
Clay – a “dirty” building material
Clay is a mixture of the different coarse sedimentary rocks clay, silt and sand as well as water. In the soil occurring minerals provide for the regionally different coloring. Thus, a high proportion of iron and copper causes a red-brown color of the clay, zinc and magnesium stain.
For an optimal binding power, the clay must not be too “fat”, ie: the clay content should not exceed ten percent. Otherwise walls and floors would break and endanger the stability of the house. For this reason, the clay was always mixed with straw or sand. At the same time, the weight of the building material was significantly reduced.
Clay was the preferred method to build the medieval house, this building material was easily available. With a few exceptions, almost every village had its own clay pit. Mostly located directly under the humus layer, clay could easily be mined and processed. As a building material, it has been used very widely: for floors, ceilings, walls, as plaster, but also in the furnace construction and for the roofing.
Clay was readily available in the Middle Ages
To build with clay, it was not always considered a particularly fine construction. Because the raw material was cheap, easy to process and could be used by anyone, the earthy material had a bad reputation.
In order not to be considered poor, they often tried to conceal their use – for example, by plasters and colored house paints, under which the half-timbered construction disappeared. In the process, cubes were often painted to simulate a stone construction.
Today we know that clay is an optimal and at the same time ecologically very valuable building material. It is frost-resistant and fire resistant, it contributes to the moisture regulation of the interior. Thanks to the high straw material, half-timbered homes have an excellent heat and impact sound insulation. Besides this the homes have a reputation to prevent pest infestation on the truss framework.
Here you see the guts, without the plaster of a home from the 1500 a.D.