Why build skyscrapers with wood?
… or how the tale of the three little pigs conditions the consolidation of new technologies.
In our previous post, we presented the 21st century as [the century of wood in construction](https://woodea.es/blog/siglo-de-la-madera-en-construccion/), and how the tale of the three little pigs has impacted the planet. Now, continuing with the analogy of the popular children’s story, we will try to explain the effect that these stories, passed down from generation to generation, have had on the perception of construction and buildings.
In the cultural imagination shaped by this story, wooden buildings (and those made of straw) are considered fragile. The wolf could blow them down with just a couple of breaths. In the popular imagination, the pigs who opt for wooden or other bio-material buildings (straw) are seen as less cautious and less hardworking.
From this preliminary idea, one could interpret that life rewards only those who are hardworking and cautious with a durable and unalterable shelter to protect themselves from the wolf.
Conclusion: successful people have brick houses.
If we continue with the analogy, the houses that protect us from the elements and provide security against the wolf are made of bricks.
But time has passed, and things have changed since this Disney film from 1933. Bricks gave way to iron in the 19th century and to steel and concrete as the star material in the 20th century, constructing thousands of homes that housed hardworking and successful pigs.
However, as the world’s population increased and people left their homes in the countryside to work in the city, there arose a growing need for transportation to get to work. And that’s when a new wolf appeared: the climate crisis, accompanied by a crisis in the quantity and quality of housing.
How to face this new crisis?
On the one hand, the shortage of housing, and on the other hand, the negative impact of traditional construction methods on the environment. How can we continue building without harming our planet?
The Global Alliance for Buildings and Construction (GlobalABC) UN Environment Program estimates that the construction of brick, concrete, and steel houses generates up to 8% of total greenhouse gases. The use and maintenance of buildings themselves are responsible, on the other hand, for 47% of carbon emissions.
And lastly, it is evident that a construction system based on extractive methods of resources that will one day be depleted is unsustainable. Water and sand are the most used raw materials on the planet. We understand the water crisis, but the sand crisis has not yet reached the general public.
To look to the future with optimism, we must seek alternative methods that provide sustainable and affordable housing and that do not affect, or affect as little as possible, the environment.
It is, therefore, necessary to transition to an industry that reduces its emissions not only in the use phase but also in the production phase of materials and components. It’s about moving to an industry that does not deplete natural resources but regenerates them.
Visionary architect Michael Green, back in July 2013, warned of this clash of interests with a very graphic image.
In an inspiring TED talk for those who see the urgent need to build differently, he questions:
How can we meet these demands with a material that allows us to build homes without affecting the environment? And he found it right outside his window, in his home in Canada: WOOD, or rather “woods” since there are infinite varieties for different uses.
And he states…
“For me as an architect, wood is a great material, the only material with which I can build that grows with the energy of the sun.”
And he provides reasoning to describe why wood is not only an excellent material for construction but also why building with wood is beneficial for the planet:
“When a tree grows in the forest, it releases oxygen, absorbs carbon dioxide, and then, when it dies, falls to the ground and returns carbon dioxide to the atmosphere or soil. If it burns in a forest fire, the carbon also returns to the atmosphere.But if that wood is taken and used in construction or in a piece of furniture or in that wooden toy, with its incredible ability to store carbon, it provides us with a great retention of this element.
One cubic meter of wood stores a ton of carbon dioxide. Our two solutions to protect the climate are obviously to reduce emissions and find a carbon storage system.“
To address these dilemmas and propose solutions, there are pioneers—those who see a little further, those who prioritize the common interest over the individual.
“Wood is the only material I use that fulfills these two functions. We understand that it is ethical for food to grow on Earth, now we need materials to build our homes to grow on Earth in this century.”
When Michael Green talks about “wood,” he is not referring to what the popular imagination recognizes as “wooden houses.” Going back to the three little pigs, the house presented in the film is not a fragile wooden construction but one related to “technical wood,” for many, the material of the 21st century.
The raw material for making wooden buildings
21st-century wood is a technological development that we call “technical wood.” It is not new, as in its modern form, it has been around for over 30 years, and laminated wood is an invention of the 19th century. It has very good mechanical and physical properties, which, at equal weight, have greater strength than steel and concrete, much more malleable, with much more predictability, and better fire resistance in case of fire.
The needs, priorities, and materials to be applied for this new era are radically different.
Although construction techniques using straw, bamboo, or even earth are being applied in single-family homes, to have a real impact on the environment, it must be used massively and preferably in urban environments. This is where, in this new scenario, the material par excellence is CLT, which stands for Cross Laminated Timber.
To create this new technological material, boards are stacked side by side in layers and joined on their short sides by joints called “fingers,” forming sheets glued together with a non-toxic and ecological adhesive. Subsequently, for greater strength, they are hydraulically pressed to create “master panels” that can reach dimensions of 3.5m x 16m. This is a blank canvas where the architect can “paint” their project.
If the top sheet is perpendicular to the previous one, forming a cross (cross), it is called CLT and is used for slabs and structural panels, while if they are aligned, they are known as GLT and are used for pillars and beams.
Therefore, adopting this new construction method should be an imperative or, rather, an urgency to mitigate the impacts of the climate crisis.
It has been proven that buildings made of technical wood (mass timber) reduce greenhouse gas emissions, fossil fuel consumption, and even, through sustainable use of the wood’s origin, protect forests and enable the development of rural areas, favoring their repopulation.
Carbon footprint and its relationship with wood. The new economic variable.
“The production of one ton of wood for construction requires a total of 5 times less energy than needed to manufacture one ton of reinforced concrete, 24 times less than one ton of steel, and 26 times less than that of one ton of aluminum.” Source: Council C.W (2004) Energy and the Environment in residential construction. Sustainable Building Series No. 1 pp1-16
In this new era, a new variable logically appears: homes should not only shelter us from the wolf but should not harm our “big house,” the planet.
In various scientific meetings and summits, a limit to global warming is established, and CO2 is recognized as the gas that contributes most to global warming. Reducing it is decided as the main strategy to achieve the goal of maximum temperature increases to 1.5º by 2050.
In this context, the EU establishes its climate change mitigation strategy through the reduction of emissions of its main contributor, the “carbon footprint.”
This concept, coined in the 1990s by Canadian ecologist William Rees and Swiss regional planner Mathis Wackernagel at the University of British Columbia, is expressed as a weight measure. An example: tons of CO2 or CO2 equivalent per year, measuring the impact an activity has on the environment.
What is the relationship between trees, wood, and carbon?
If we remove all the moisture from a trunk, 70% of its structure is carbon. That’s why a tree or a group of them, a forest, is a carbon deposit, and even cut and placed in a construction, it keeps it in its mass, as can be seen in the following video “Follow the tree.”
Wood for Good - The Story of the Tree
So far, the construction industry has not been obliged to address the inefficiencies of its processes regarding the carbon footprint. It is located in what is called “diffuse sectors.”
This will change in the future due to the high impact of constructions throughout their life cycle, and this activity must be framed in the mandatory emissions market where each ton of CO2 is measured in carbon bonds or CERs (Emission Reduction Certificate).
This predictable change will produce a new variable in construction budgets. In addition, we will witness changes in regulations that are already applied in some European cities such as Bordeaux and are already being studied in some Spanish cities such as Valencia and Lugo, moving from thermal regulations to environmental regulations, directly affecting the choice of materials and construction systems.
As architect David Sebastian mentions in his book “Building in Height in Wood.”
“…a new paradigm is needed where profitability and sustainability are linked. In other words, a buildability inversely proportional to emissions and resource consumption. A model that can densify cities and allow their progress but limit their growth and excessive occupation of the territory at the same time. A model where poor resource management is penalized mechanically, and conversely, responsible resource management is rewarded.”
And he represents this position graphically.
With all these backgrounds and in this context of the climate emergency in which we are immersed, it is necessary to think about different strategies to reduce the carbon footprint.
“If wood did not exist, we would have to invent it,” says our CEO Octavi Uy. It is a “supermaterial that no modern alloy has managed to beat,” explains this article and many assertions from leading universities, architects, and scientists.
With all this, we repeat, affirm, and share what architect Alex De Rijke says:
“The 19th century was the century of iron,
the 20th century was the century of concrete,
and the 21st century will be the century of technical wood.”