Has building in wood got a future – are we not endangering our forests?

Wood grows in great quantities in our native forests and requires only a fraction of the effort to process than other materials. Wood is ecologically without equal, touches our senses and, of all building materials, is closest to man (it breathes, smells, works and, in time, acquires a natural patina).

For example, in Austria more trees grow than are used. Only 19 million sq.m of the annual additional growth of approx. 30 million sq.m are harvested and processed – that means our forests are expanding year on year. A good feeling in today’s world of diminishing resources.

Wood offers lots of advantages – and these must be put to use for the good of oneself, one’s own family and society in general!

Back on top

Are timber buildings long-lasting and/or durable?

Wood is a natural building material and bio-degradable. Therefore it produces no waste material. Yet it is durable as evidenced by the over 1000 year old stave churches in Norway, the over 1500 year old temple complexes in Japan and China and artefacts from Egyptian tombs that are over 3500 years old. But who wants to build to last for such an eternity? Nevertheless, the fact is that wood has an almost unlimited life providing of course that is has been properly dried and is protected from prolonged exposure to moisture.

Back on top

Does wood not require a lot of maintenance?

Ventilation plays a particularly important role in exterior wood applications (such as facades). A facade built in accordance proper criteria prevents the ingress of moisture into the fabric of the building, allows surface water to run off and, thanks to good air circulation, ensures that the wood components dry quickly. Woods such as larch, oak etc. have a natural resistance to biological degradation and do not require further treatment. However, one must be aware that the appearance of wood will change in the course of time because of the effects of weather (wind, sun, rain…). The colour of untreated wood will vary from brown to silver-grey to dark brown according to altitude, climate and position (intensity of weathering). These colour variations are merely a fine surface layer, which covers completely healthy wood beneath.

If this natural greying process is not to one’s liking then a façade can be treated with a scumble. This entails regular inspection as well as regular maintenance of the façade depending on weathering conditions.

Back on top

Wood is flammable – is it still safe to be inside a wood house?

Even if wood is on fire, it has been proven that it behaves particularly well and advantageously from the user’s point of view in the event of a fire. Wood burns slowly and evenly and the burn rate can be precisely determined. The burn rate for spruce is 0.66mm/min. By appropriate dimensioning, the various fire regulations can be met without any problem.

Whereas a non-flammable construction would have collapsed, a timber construction will continue to resist fire. This fact was warmly welcomed by the authorities, in particular the fire fighting authorities, so that today multi-storeyed timber constructions are permissible; in Salzburg for example up to four storeys are permitted, in Norway even up to six.

The fact of the matter is that fire risk in a timber building is no greater than with any other type. It is the furnishings, carpets, curtains, which give off toxic fumes and lead to smoke inhalation poisoning.

Back on top

Are timber houses comfortable?

The comfort of an apartment, a house or even a workplace is decisive for the wellbeing of the residents. In summer, the heat should be kept out, in winter the warmth should be kept in. Furthermore, the comfort inside a house is dependant on how much air can get in and out. All these criteria are more than fulfilled by the latest generation of timber houses. Thanks to excellent thermal insulation, timber houses ensure optimal living conditions all year round – low energy or a 3 litre house is standard. The assembly of the walls using organic materials contributes to the feeling of comfort. For example, wood has the capacity of regulating relative humidity by absorbing or giving off water.

Back on top

Are timber construction badly soundproofed?

This preconception regarding soundproofing is certainly an issue with badly built buildings but not if the wall and ceiling constructions and joints are well designed. On one hand, soundproofing is achieved through mass, on the other hand through the multi-layer or sandwich construction method. This combination as very commonly used in timber construction, achieves soundproofing values, which can match those of conventional buildings or even exceed them.

Back on top

Are timber houses cheaper / more expensive?

Quality has its price, let’s be clear – and that has nothing to do with the method of construction. Some facts about timber construction: timber construction is light, quick, dry and clean. Precise planning by a multidisciplinary team and a high degree of pre-fabrication reduce building costs and eliminate expensive improvisations during the building of the structure on site.

Opportunities for economy are also available in foundation laying. Timber construction requires less mass because the dead load of the structure is lighter (1/6th that of concrete), which also has a very positive impact on poor ground, on slopes or when adding a storey or an extension (it is very rare that a structure needs strengthening in timber construction).

But it is not only the cost of construction that needs to be taken into consideration in producing an exact cost calculation. Timber construction is cost-effective over a number of years because of its low running costs. Low energy or 3 litre house standard are considered normal from an energy standpoint.

Back on top

What risks do fungi and insects present?

Wood is the only building material that is biodegradable. When a tree dies, it is biologically degraded by fungi and insects. The nutrients contained in the wood enrich the humus, which stimulates the growth of young trees. Growth and degradation are part of the natural cycle.

Like every living being wood-degrading organisms require water, air and a sufficiently high ambient temperature to be able to develop. If one of these criteria is absent, the prerequisites for wood degradation are no longer present. Wooden pillars from the age of "pillar building" have been preserved till today because they were not exposed to air. Wood lasts for ever, even when dry. In a heated house, the low humidity content of wood eliminates every risk of degradation. The same applies to structural components, which occasionally get wet but then dry out again.

Back on top