Wood as a building material – doesn’t that sound a bit old-fashioned? Not at all! Thanks to its excellent properties, wood has not lost any of its popularity as a building material. Thanks to current prefabricated house trends, the development is even more in the direction of increasing use. But what qualities are they that make the wood appear so irresistible? And is wood always just wood? One thing quickly becomes clear: this building material raises many exciting questions. And this article now provides the answers!
A SCARCE RAW MATERIAL?
Wood is a popular material. Occasionally, however, the use of wood as a building material is more or less questioned by various social groups that have dedicated themselves to natural, organic, and ecological products. One of the main arguments is an (assumed) shortage of local wood stocks and thus damage to the ecological balance. However, the numbers speak a different language here.
WOOD AS A BUILDING MATERIAL
Wood – and all experts agree on this – is still a technically extremely high-quality material and building material. It also exerts a timeless beauty in the exterior and interior design, which enables us to use wood to create particularly comfortable rooms for living and living. In the construction sector in particular, however, the physical values such as strength, bulk density, or moisture are, of course, also of decisive importance.
- Domestic softwoods, when air-dry, have a bulk density of 0.45 to 0.55 g / cm³, for hardwoods, this value is between 0.60 and 0.70 g / cm³. Synthetic plastics such as polypropylene are at least twice as heavy as spruce wood; concrete is four times as heavy and steel are good seventeen times heavier.
- Wood contains only small amounts of physically adsorbed water so that the average humidity is only around 7 to 15 percent by weight. Therefore, the natural material, especially in its porous structure, has a positive effect on humidity regulation in closed rooms and functions as a so-called buffer between the indoor air and the building’s outer skin. Tip: Interior rooms should, therefore, remain untreated on walls and ceilings or only be provided with diffusion-open paints, waxes, or oils.
- In terms of their strength, wooden building materials do very well compared to concrete or steel. The tensile strength of spruce wood alone, measured lengthways, is between 80 and 90 N / mm², which means that this type of wood is three times more resilient than traditional structural steel. On the other hand, the maximum pressure load on the spruce is only 45 N / mm² lower, but still very respectable, so that wood is difficult to beat due to its good structural properties and load-bearing behavior.
OVERVIEW OF WOOD BUILDING MATERIALS
As a building material, wood can be processed in a very diverse way, considering its properties and possible uses. A basic distinction is made between solid wood products (e.g., solid or structural timber) or wood-based materials.
When lumber is height, width, and thickness of the most important quality criteria, the selection is made either visually or mechanically, both according to load-bearing capacity and appearance. However, the wood moisture in the upper range classes must not exceed 20 percent.
Particularly appreciated and ideal for demanding construction projects is the construction timber. With its technical parameters, it is qualitatively far above the strict technical characteristics of the building inspection regulations for normal structural timber, in terms of sorting, drying, and cutting.
Important and especially popular as a material for interior construction: glued laminated timber and cross-laminated timber! When laminated timber superposed, crosswise board layers are glued to solid wood panels. In glulam, the gluing takes place uniformly along the fiber direction. Both types contribute significantly to an expansion of the areas of application of sawn timber, which was almost unimaginable a few years ago.