Modern times are full of surprises. Who would have thought that timber would be even considered as a super-structure material for multi-story construction?
The logic seems counter-intuitive. Timber burns and things eat it. Having said that, it is an easy to build with material. And we are told it is more sustainable.
But how true is the positive sustainability line? We often have to take the experts word for it, and relying on the word of others can at times be very unprofessional. People who push a concept may have ulterior motives or stand to benefit from the push, and we know that data and statistics can be presented to favor a point of view.
Without authenticating the scientific data on timber’s sustainability, from a superficial lay-persons view, there are concerns. Of course, timber can be regrown, which is its big sustainability selling point, but is the whole concept debatable?
Consider this; to grow timber, land must be cleared at great cost in terms of energy use and environmental damage. Then it’s planted and grown over many years, again at significant cost without economic reward. Harvesting means destructive and energy consuming land-clearing again. Then it’s loaded and transported to mills for energy consuming cutting, then transport again to be impregnated with poisonous chemicals to delay white ant and rot damage, then transported to merchants for handling and storage, then transported to site where energy consuming power tools cut it and nail it in place.
Then, typical timber construction involves the use of a lot of galvanized steel fixings, plates, straps and hold down rods, and plentiful consumption of plywood and other glued products. All these extra components have their own complex and resource consuming supply chain. Then finally, in a temporary sort of way but still important, construction noise and dust for neighbors is extreme.
Then, once in a building, timber construction has design faults such as; it gives dubious protection against the ballistic impacts that big cyclones kick up, it creates cavities for small vermin like black ants and spiders, it necessitates the construction of termite barriers which need constant maintenance including sometimes continued use of poisonous chemicals, when exposed it needs repetitive maintenance and re-painting, it has poor acoustic blocking performance, it has no thermal mass which is essential for interior passive climate control, and it can burn.
Timbers combustibility is perhaps the biggest concern in high rise construction. Fire protection measures for conventional concrete and steel construction (at big financial and environmental cost) are onerous. For timber high rise construction, it is huge.
Also, an argument for timber high rise construction is that the timber superstructure chars which prevents more fire damage to the material. What building owner would want their superstructure to char, then have to demolish and reconstruct?
All this must be included in a genuine consideration of, and scientific measurement of the sustainability of a material or construction method. Are these things measured this way, including the measurement of human injury, trauma or death from the negative effects of high winds or fire, or the cost of rebuilding or repair from the destructive effects of the many things that can attack timber?
A simple mental test that we can do right now, without any scientist being involved, is compare two types of houses, an old timber Queenslander and a modern house of masonry, concrete and steel. If you left them both unattended for a hundred years, which one would be a pile of dust and which one would still be habitable?
And let’s not forget the children’s story of the three little piggys and what happened to the piggy who built a house of sticks, and what happened to the piggy who built a house of stone.