Wood is by nature a very durable substance. They found remains of wood used by the Romans nearly intact thanks to a combination of circumstances that have protected it from external attacks. From the organisms that attack wood, the most important is the fungus that causes drying of the root when the wood is wet.
Walnut, redwood, cedar, mahogany and teak are among the most durable woods known. To preserve the wood you must chemically protect it. The method used is to impregnate with creosote or zinc chloride. It can also protect from weather by covering its surface with varnishes and other substances that are applied by brush, spray gun or bath.
Wood drying. The freshly cut wood contains much water, one-third to half of its total weight. The process to remove this water before processing is called dry wood, and is done for many reasons. Dry wood is more durable than fresh wood; It is much lighter and therefore easier to transport; It has higher calorific value, which is important if you plan to be used as fuel; Wood also changes shape during drying and this change must be done before drying.
Wood structural systems. The wooden contrition adopt, as a rule, either of two ways: the construction with lightweight frames and heavy timber construction. Construction with lightweight wooden frames uses very close slender limbs together to form walls, floors and ceilings in a system called platform frame construction. The heavy timber construction uses larger members arranged with a system of posts and beams. Lightweight construction with wooden frames or heavy timber construction can be combined with masonry structures for increased fire resistance and load capacity.
Frame construction platform. The platform frame construction is an economical and flexible construction. It is widely used for single-family and multi-family dwellings, rather than for apartment buildings and low-rise small commercial structures. As this system is manufactured largely in place and the structural members are small, it is particularly suitable for use in cases where unusual distributions or irregular shapes are required. The platform frame construction incorporates easily and discreetly, mechanical systems and other building facilities. The platform structure is a system of slab and walls.
Heavy timber construction. The heavy timber construction is characterized by its high resistance to fire (it has a fire resistance substantially higher than the apparent steel), high load capacity and the unique aesthetic qualities of the apparent wood frame. Structural members for this type of construction may be solid wood or plywood glued together. Heavy wooden structures for commercial and industrial low-rise residential construction and buildings are used. As the structural members are usually, prefabricated construction time on site is usually very short with this system. However, the larger dimensions of the structural members make this system less appropriate for the platform structure, in buildings or very irregular distribution.
Is it really an unsafe material? One of the most common prejudices has to do with the material’s resistance to fire, unaware that this, while it is combustible, is a poor conductor of heat. “The wood starts to burn on its periphery, and as it becomes coal acts as a heat insulating combustion stopping the fire and allowing the inner material to remain intact, which does not occur with the steel becoming soft when heated and collapses”. A second shadow extends over the wood as a structural material is prejudice with respect to moisture, and in front of it are clear security mechanisms: The construction is relatively high so that the base remains isolated from plants and grassy areas. Using barriers such as bituminous membranes, polyethylene, between wood and foundations, ensures high impermeability.
For example, the wood has an exceptional behavior in seismic areas, because it better absorbs the dynamic forces of earthquakes due to its flexibility, elasticity and low weight. In fact, a wood structure may be 5 times lighter than a concrete one, which reduces the inertia avoiding acceleration of the structure and collapse. Moreover, wood also acts as insulation from cold or heat as the temperature misconducts; 1 cm thick wood works as 4 centimeters of clay or brick or 10 cm of concret.