Replacing Carbon-Intensive Steel And Concrete
Modern buildings are constructed with concrete and steel beams in mind. This is because these materials are both cheap and easy to design with. But they also come with serious drawbacks.
Concrete, especially reinforced concrete, lasts only a few decades before needing to be demolished and rebuilt entirely. There might be some new technologies solving these issues, like hemp or graphene concrete, but none are really mature enough to be deployed globally just yet.
Besides durability, the carbon emissions from the production of steel and cement are also a serious concern. Together, steel and cement are responsible for 158% of the world’s greenhouse gas emissions. Here too, green hydrogen or carbon-free cement technology could be an option, but it will take time to become mature enough.
Luckily, a new method of building that is carbon negative (capturing carbon) can be used today, using maybe the oldest building material known to man: wood.
The Limitations of Wood
Wood has been the basis of construction for most of the world for millennia. As it is a renewable resource that also sequesters carbon in its structure, it would make sense to keep using it on a large scale today.
Today, wood is mostly used for houses and smaller buildings. This is because a few problems have made it fall out of favor for other materials for large buildings, first stones and bricks, and today concrete and steel:
- Flammability, with old wooden buildings extremely vulnerable to fire.
- When entire cities are made of wood, catastrophic massive fires were always a danger, like when the entirety of London burned down in 1666 in the Great Fire of London that lasted 4 entire days.
- Wood is limiting how tall buildings can be made with it, leading to modern cities preferring other materials.
- Most ancient construction techniques handle moisture poorly, leading to mold and rot of wooden structures.
So any comeback of wood as the main construction material would need to address all of these issues. Luckily, a new technology called “mass timber” does exactly that.
Mass Timber
In its basic concept, mass timber is very similar to common plywood, but deployed at a much larger scale. This can done through a variety of techniques used to glue and press the wooden pieces together. Cross-laminated timber (CLT) is usually the main technique used for mass timber today, due to its strong structural integrity.
Source: Naturally Wood
A key advantage of this method is that it can create very large beams, without having to rely on waiting for trees to grow to the required size for centuries. This makes it both more economically viable and avoids the cutting of old-growth forests.
“About 30 years ago, builders in Germany and Austria began experimenting with techniques for making massive wood elements out of this readily available lumber. They used nails, dowels, and glue to combine smaller pieces of wood into big, strong, and solid masses that don’t require cutting down large old-growth trees.”
Knowlable Magazine
Remarkable Performance
Using mass timber techniques, beams up to 50 meters (164 feet) long can be created. For floors and walls currently made of concrete, CLT panels up to 50 centimeters thick can be used.
Source: Stora Enso
These wood composites are actually stronger than steel by weight. The only limit is that they are less dense than steel, so require more volume.
This means that for the tallest mass timber building, a mix of steel and mass timber is used to reduce the size of the structural beams supporting the structure.
Tall Wood Building
Today, the largest mass timber building is the 25-story Ascent skyscraper in Milwaukee, completed in 2022.
Source: Thornton Tomasetti
In total, there are currently 84 mass timber buildings eight stories or higher either built or under construction worldwide, with another 55 proposed.
For now, this is mostly a European phenomenon, with 70% of mass timber buildings made in the region. In North America, steel & mass timber hybrid buildings are more common.
What is likely to give a big boost to this method is the 2021 approval of mass timber construction up to 18 stories tall by the International Code Council (ICC). The ICC is responsible for publishing the International Building Code which is the template used by construction jurisdictions all around the world.
So this should allow this technique to stop being a custom design requiring tedious special permitting each time, and instead become a standard construction method.
Mass timber can also be used for industrial buildings, with for example datacenters for Microsoft being built using CLT.
Fire Safety
A big factor in getting the ICC approval for tall mass timber buildings was the demonstration that they are fire-safe. This is a particular concern for tall structures, as any fire needs to be slow to spread, giving time for the people inside to evacuate and for firefighters to have a chance to put the fire out.
For example, materials in conventional skyscrapers are required to maintain their integrity in a fire for three hours or more. For this reason, until very recently most local safety codes banned wood from being used in tall buildings.
So how can mass timber achieve this? Mostly by being made of wood, but not being a normal wood beam in any other respect.
This was demonstrated in gas-fired chambers to test the mass timber, or even setting fire to a mock-up of mass timber building and recording the results. Only after these demonstrations were performed, did the ICC accept that it was a safe enough material.
It works because the mass timber pieces are very thick and at the same time extremely dense. This has 2 effects drastically reducing its flammability:
- The outer layer quickly forms a thick layer of char that insulates the interior from much of the heat.
- The material density and thickness cause most of the wood to not have enough oxygen to catch fire.
Opportunities of Mass Timber
The main promise of mass timber is to replace with a renewable resource the unsustainable consumption of energy and sand required by concrete & steel buildings. But it has also a few other advantages.
Lighter Buildings
As mass timber is actually stronger than steel at an equivalent mass, and much lighter than concrete, the same style of building that would have been very heavy becomes much lighter when made with mass timber.
For example, this has allowed the company Stora Enso to build with mass timber a 12-level building above the E4 highway, which would not have been possible with a heavier design.
Source: Stora Enso
Thermal Isolation
Wood is in general a good thermal insulant. So it can help make the building more energy efficient, although it does not remove the need for additional insulation layers.
Carbon Capture
A good example of mass timber potential in reducing the construction industry’s carbon emissions was given with the 18-story Brock Commons building in British Columbia.
It saved 2,432 metric tons of CO2 emissions compared with a similar building of concrete and steel. Of these emissions saved, around 1/4th were for the emissions produced by manufacturing the steel and cement, and the rest in the CO2 locked in the wood itself.
If properly cared for and/or recycled, this could turn our cities into a permanent carbon sink. A major change compared to concrete requiring a new cycle of carbon emission every 50-70 years when rebuilding degraded reinforced concrete buildings.
Esthetics
In general, people prefer the feeling of living material to the colder and more industrial feel of concrete and metal.
As there is a growing backlash against brutalist modern architecture, more wooden buildings could make downtown cities more alive and friendly, leading to a premium in the associated real estate price.
“People get sick and tired of steel and concrete. With its warm, soothing appearance and natural variations, timber can be more visually pleasing. People actually enjoy looking at wood.”
Ted Kesik – Building scientist at the University of Toronto’s Mass Timber Institute
Challenges of Mass Timber
Because mass timber is so different from the multi-story buildings we are used to, they require a bit of rethinking.
Construction Methods
Because mass timber is manufactured in dedicated factories in the first place, this leaves the opportunity to design the mass timber element in advance for a corresponding building.
This is part of the larger new model of construction called integrated design. In it, architects work in tandem with installers and factories to have the exact sizes and shapes of elements predetermined.
Much like Ikea furniture, strong points and holes can even be pre-drilled or cut with advanced computer-controlled machinery to match their future spot in the building.
This is a much more detailed procedure, giving more control to the architects of the final design. It can also make the construction itself 40% faster than with traditional workflow and building methods.
“Mass timber buildings tend to be manufactured more like automobiles, with all the separate pieces shipped to a final location for assembly. When the mass timber building shows up on-site, it’s really just like an oversized piece of Ikea furniture.”
Ted Kesik – Building scientist at the University of Toronto’s Mass Timber Institute
Moisture & Insects
More than fire, a serious concern with any wood building is damage to the material by fungi or insects.
Moisture management is therefore very important in the design of mass timber buildings:
- The material should not get wet during transportation or during installation.
- An extensive heat and ventilation system that does not accumulate moisture needs to be installed in the building.
- Risks of water damage (leaky roof, floods) need to be taken into account when deciding on a mass timber building.
Insects can also be kept at bay with special treatment of the wood with pesticides. In addition, physical barriers like a mesh can be added to where the mass timber meets the ground.
Sounds
Wood transmits sound very well, which can become a serious issue in a large building with hundreds of apartments or offices.
This means that architects using mass timber will need to dedicate a special effort to adding sound insulation materials. They can also reduce sound transmissions by adding space between walls and installing raised floors or other methods known to increase acoustic insulation.
Moving Toward Mass Adoption?
Timber might be soon making a massive comeback in the construction of most of our cities’ buildings, thanks to the emergence of mass timber technology. It can create lighter buildings, that are also more sustainable in every way.
It will however require a few steps to be taken for it to turn from a curiosity to a significant percentage of new builds:
- Reform of local construction codes to take into account the new international norms.
- Training of architects and builders on how to best use this new material.
- Deploying at scale the manufacturing facilities to produce enough mass timber.
- Maintaining a robust certification system to ensure that the wood is cultivated in a sustainable way.
All of this will take quite a few years at least, but as the technology is ready, and more carbon taxes might come into action, this could be quicker than most expect.
Investing In Mass Timber
There is currently no mass timber manufacturer or construction firm dedicated to the technique that is publicly traded.
So the best way to capitalize on the return of wood into building more than just individual homes is likely to invest directly in the production of the material itself.
You can invest in wood and timber-related companies through many brokers, and you can find here, on securities.io, our recommendations for the best brokers in the USA, Canada, Australia, the UK, as well as many other countries.
If you are not interested in investing in individual stocks, you can also look at the iShares Global Timber & Forestry ETF (WOOD) or the Invesco MSCI Global Timber ETF (CUT) which will provide a diversified exposure to the wood and timber sector.
Timber Company
Weyerhaeuser Company (WY +0.96%)
Because wood production can be highly vulnerable to environmental effects like wildfire, drought, insect infestation, etc. it is best for investors to have as diversified as possible exposure to it.
This is what timberland REITs (Real Estate Investment Trusts) offer, by gathering in a publicly traded instrument the ownership of a massive amount of woodlands.
Weyerhaeuser Company is the largest Timberland REIT listed in the US, with 10.5 million acres held in the U.S. and 14 million acres licensed in Canada. It also has 35 manufacturing facilities across North America.
Source: Weyerhaeuser
Weyerhaeuser is recognized as a leader in sustainable forestry practices, with replanting managed through its own technology and tree varieties. It is also keeping trees along rivers to preserve them from damage when logging and follows on 100% of its land the sustainable forestry initiative standard, cutting only 2% of its forests every year.
Source: Weyerhaeuser
The company’s scale also allows it to deploy efficient procedures to reduce cost and optimize operations, leading it to be a very low-cost producer.
Source: Weyerhaeuser
In addition to the local US and Canadian markets, the company also exports wood logs, mostly to Japan (66%) and China (25%).
Because of its diversified geography and export capacity, the company is a lot less vulnerable to any individual local real estate market dynamic than smaller competitors.
Overall, as we are looking at reducing carbon emissions, demand for wood & timber is likely to be growing for the foreseeable future.
Companies like Weyerhaeuser would be in a prime position to benefit from an increased demand for timber, and a very reliable supplier for any new manufacturer of mass timber looking to establish a steady supply chain.