Why is Wood So Good?

Wood has played a vital role in construction for thousands of years.  Dwellings as old as 10,000 years show evidence of wood. Before steel and concrete, timber was the most used material in construction. For starters, here are some of its best attributes:

• Its high tensile strength is even higher than steel!
• It can undergo intense force without physical deformation.
• Flexible and light: wood weighs four times less than cement (for the same force exerted).
• It has a good force / weight ratio, even when compared to steel, allowing for lighter, more slender structures.
• It has a remarkable ability to withstand earthquakes. The combination of elasticity, high tensile strength, nails, fasteners, and screw allow for wooden structures to withstand strong seismic events by facilitating the absorption of seismic waves through deformation

“Environmentally, there is almost no equivalent to wood in terms of construction materials”.

• It is an excellent insulator for noise and temperature.
• Comparatively, it's around 10 times less conductive than concrete.
• Its breathable and hygroscopic nature also guarantees for good humidity control and high air quality.

Wood’s limitations:

• It is more easily degradable than concrete, although this can be reduced by treating the wood adequately and using the correct assembling techniques.
• Susceptible to wet rot, mold or damage by vermin.

Why is wood environmentally friendly?

Wood can be harvested as a crop and replenished. Arguably, some species grow slower than others and need longer to regenerate which makes replenishing slower than consumption – but this remains a more immediate way to balance off the resources that are being extracted. This can be compensated by other fast-growing species such as bamboo, which is widely used in Asia for flooring and internal finishes.
The key to ensuring wood remains sustainable, is to use every part of the tree in the construction process. It might otherwise be impossible to keep up with the extraction rate and preserve the carbon sinking role of forests.

Interesting facts around timber:

• A recent study by the Aalto University has demonstrated that if timber was used in 80% of new residential buildings in Europe, they would store the equivalent of around 47% of the annual emissions of Europe's cement industry - approximately 55 million tons of CO2 per year!
• Another study, by Austim Himes from the Mississippi State Department of Forestry, shows how substituting mass timber for conventional building materials would contribute to saving 69% of emissions per construction project.
• Using wood in 50% of new urban constructions may achieve 9% of 2030 emissions reduction goals.

Timber usage in the UK and Europe

Wood is safe, sustainable and 100% renewable – what’s not to love?

Yet the percentage of buildings in the UK that rely on it for their bearing structure is impressively low (estimated to be less than 25% of new homes).

Recent disasters linked to building materials have meant a tightening of policies on materials considered more dangerous in terms of fire hazard.

After the Grenfell fire, the UK introduced new regulations that “outlaw the use of combustible materials on the external walls of any building over 18 meters tall,” Dezeen reports. Recently a further tightening of these regulations was applied to the London area, where the rule now concerns all buildings, regardless of height.

As Andrew Waugh told Dezeen, combustibility and fire performance are two different things and as such they should not be used interchangeably.

In a world in which research advances at incredible speed, such legislations are quickly becoming obsolete. Wood is a clear example of how building regulations can act as a hindrance.

Timber buildings are in fact designed to meet stringent fire resistance regulations and a wooden frame is no more dangerous than a concrete or steel one if designed correctly. Most importantly, depending on the height of a timber building, it will not collapse for a certain amount of time after a fire starts(depending on its height), in order to allow for full evacuation in worst case scenarios.

Wood has the additional advantage of not being subject to thermal deformation, like steel, nor to burst when temperatures rise, like concrete.

For this reason, in Europe there are ever more projects incentivizing the use of wood in construction. One of these, funded by the EU, is Build-In-Wood. The project’s goal is to drastically increase the proportion of timber in construction. Its 21 partners, from 11 countries (including the UK), are researching new components and better building systems that, together with ad hoc design guides, are aimed at making timber the natural choice for building materials.  

Sources:

https://www.architectmagazine.com/

https://www.renneritalia.com/‍

http://www.woodenbuildings.it/

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