When it comes to building materials, wood doesn’t always draw the most attention as the strongest in the bunch. That honor usually goes to concrete and steel – steel embedded in concrete provides support and a foundation for tall buildings, while concrete increases tensile strength and can be formed into a variety of shapes with the help of rebar. Wood, on the other hand, decays and is vulnerable to moisture damage and fire.
That’s not necessarily the case anymore, thanks to the development of advanced timber. New materials like glulam, or sheets of timber bonded with moisture-resistant structural adhesives, can be produced using two to three times less energy than steel, making them environmentally-friendly alternatives to other building materials. Granted, this requires the beams to be burned at the end of their lifespan, but glulam still has an equivalent or better environmental profile compared to steel, not to mention a lower cost.
Among engineered wood, there are some varieties more commonly used among hobbyists – MDF, plywood, or particle board for instance. Others, like Cross-Laminated Timber (CLT) are more common among building materials. While CLT buildings have existed for decades, recently major cities like Stockholm and Vancouver have seen a resurgence of timber construction. Since wood can theoretically store carbon for the entire length of its lifespan, up to 0.8 tons in a cubic meter of spruce, some architecture firms like Oslotre are building houses with a negative carbon footprint.
Projects like Sidewalk Labs and Masthamnen are proposing entire neighborhoods and skyscrapers built from advanced timber. Compared to International Style architecture, characterized by gray concrete, shiny metal, and glass, this movement could be a step towards returning to natural architectural forms. Given the stress reducing effects of green spaces in cities, engineered wood buildings could bridge the gap between modern architectural styles and natural woodlands.
“Granted, this requires the beams to be burned at the end of their lifespan”
Why in particular does it require burning? As opposed to stuffing an empty coal mine with them, or pulping them etc.
So you can release the carbon dioxide back in the atmosphere. Just kidding, I have no idea why author says that. Wood looks like its very near that perfect place where it can be both resistant enough, degrade without causing much environmental damage and the environment incentives to have forests are obvious. Does anyone have good sources of info on varnishes and glues and how they affect woods ecological impact? Would love to know more.
Author thinks concrete has good tensile strength and that rebar is used to make molds, thinks wood can’t be recycled, even thinks buildings with larger footprints will allow for more room in cities. How did this make the blog???
Unless new materials let you make taller buildings, they won’t magically increase space in cities.
You can also just let them rot.
Rotting releases back the locked carbon.
Ehhh…. So does burning.
All this quibbling about the carbon in wood. Understand that carbon tied up in biological processes is really in a closed cycle. Photosynthesis-driven plants convert carbon dioxide and minerals into sugars and fibers, and when those are consumed, either by being eaten by animals or rotted by bacteria, or by burning, that carbon is released again, Wood can store this carbon for a very long time – centuries, in fact. But all of the carbon that went into that wood will eventually come back out, no matter what you do with it. Even if you DON’T cut down a tree and use its wood, it will release its carbon eventually, through rotting and/or fire, sometimes faster than it would be if used in construction. The only reason that herbivores are a major contributor to carbon buildup in the atmosphere, is that they eat plants that are very young, taking that long-term carbon storage mode out of the cycle.
The argument that wood is recyclable doesn’t hold much water, though – each reuse of wood has a shorter lifetime. Particle board doesn’t last nearly as long as solid wood, and almost all paper is very short-lived. Sheet and web paper -> newsprint and cardboard -> paperboard -> padding material, with most of it shunted to landfills (and subsequent rotting) at each step.
Carbon is far different than CO, CO2. Why are the biggest Global waring alarmists and media so careless with basic materials science?
Because most people skated through High School Chemistry classes?
It needs to be burned for the same reason that old wooden telephone poles have to: the glues and additives are toxic, so the wood won’t decompose. The wood cannot be pulped for paper or cardboard because of it, and it can’t be re-used for furniture or other items because it would expose people to the toxins. The only place it can go is a waste incinerator or a landfill.
If it’s too toxic to make furniture, chipboarded and formica-ed over, it shouldn’t be in your walls. If you can’t use telephone poles for roof beams in the second place, then you can’t use the same stuff in the first place on your structural wood. i.e. the whole thing doesn’t work if you have to use the same preservatives as on telephone poles.
Indeed.
The laminated beams can’t be made to last the elements without making them toxic as building materials.
LANDFILL!!! The obvious sequestration method. If done properly, this method of sequestering carbon is often overlooked, indeed shunned, not for scientific reasons, but for political and ” ewwww” factor reasons. Wood fibers, whether in paper, or solid forms are often recovered intact from archaeolofical digs., some thousands of years old. This is a clue that putting wood products, and yes even plastics, in an appropriate, anaerobic environment, can lock the carbon away for millenia. Wake up.
Maybe call it neo peat or XXIst century bog or something like that that sounds eco-friendly. I’d blend it and filled unused mine shafts/corridors/whatever its called where they dig out coal and rest.
Well, yes, of course. That reminds me of when they’ve dumped all kinds of junk into the ocean and called them “artificial reefs”.
But hey, nature has sequestered incredible amounts of carbon underground, in what we now use to fuel our civilization, so we’re just doing nature’s work with landfills.
I’m not even sure that I would disagree with that…
Because the glue used is not biodegradable — if it was it would make a poor choice for building material.
I’m assuming this is to recover the stored energy. (Since the article is talking about steel being energy-intensive).
Obviously it has the negative of releasing carbon back into the atmosphere.
Laminate wood and plywood construction looks cheap – like temporary sheds – unless they’re painted over or covered otherwise. A city made of steel, brick and stone is made for the centuries and it consumes less energy in the long term than replacing sagging or rotten wooden structures every couple decades, not to mention the fire hazards.
For example, the reason why they build traditional log houses with large gaps around window and door frames covered by planks is because the building will shrink in height by as much as 2 feet within its lifespan. If they didn’t leave enough gaps, the windows would be crushed and the doors would get jammed.
There’s also the issue that bonded/laminated wood releases volatile compounds due to the plastics used to bind them. When you stuff the wood full of fungicides, flame retardants, stabilizers and epoxies, it becomes a health hazard much like bonded fiber board. It’s a well intention, but the people who want to reintroduce wood construction are working more under idealism than practical realism – they see wood and they think it must be environmentally sound, when the practical reality is anything but.
And, the amount of wood stored in buildings – in terms of carbon capture and storage – is absolutely minimal. As a replacement of concrete, which is responsible for a great deal of CO2 emissions, you must be suggesting to build highway ramps and bridges out of wood which is simply not feasible. That is however where most of the construction materials are spent – not in skyscrapers and individual homes, but in the infrastructure around them.
If you want to find a place where you can use a lot of wood, start building railways with wooden sleepers under the rails again. Back in the 19th century the railways were consuming so much timber that they couldn’t log fast enough to replace them. Building a few “skyscrapers” out of wood is nothing, it’s just playing tiddlywinks for “green” credit.
Log home shrinkage is neither an example of rotten wooden structures nor fire hazards. Old log homes shrank because green wood shrinks as it dries, and they were built before you could order kiln-dried lumber to be delivered hundreds of miles within the week. Mostly they were built on the edge of civilization, using material that was available with nothing more than an axe and a few guys, and in a hurry because winter was coming.
You obviously haven’t seen much in the way of modern laminates. It isn’t Home Depot plywood. Try watching the British TV series “Grand Designs” (Netflix) which contains several examples using GluLam and/or CrossLam. Get a clue before you spew.
Wooden sleepers? WTF? You literally chose a poster-child for selecting concrete over wood. High compressive loads, moisture-laden environment, poor air circulation, proximity to composting bugs. The only reason wooden sleepers survived 2 years was due to creosote. Perhaps you’d like to infuse them with copper instead, LOL.
You’re also missing the point about using more timber in construction, including high-rise construction. It isn’t necessary to use it exclusive of concrete in order to make a difference. A concrete core has a lot of thermal mass which can be advantageous to low-carbon footprints. Enclosing such a core within a CrossLam shell can provide great thermal efficiency requiring vastly reduced heating and cooling. Note that even in homes built purely out of CrossLam, foundations still nearly universally contain concrete, for pretty much the same reasons that the railway industry switched to concrete. High compressive loads, moisture-laden environment etc. It is possible to using pilings under a GluLam or steel frame, with the space between the ground and subfloor filled with insulating foam over gravel, and that way you only need concrete in the pilings.
You fail to understand the point. A log home sagging is an extreme example – but kiln dried wood isn’t exempt of the effect. Laminated wood too responds to changes in temperature and humidity, and slowly degrades – it only really works in climate controlled environments, basically for interior structures only.
> You literally chose a poster-child for selecting concrete over wood.
That was the point – the infrastructure in general is where we spend most of our construction materials, and wood was displaced as the material of choice for good reasons. Again, an extreme example, but true in so many other cases.
> It isn’t necessary to use it exclusive of concrete in order to make a difference.
But that’s how it’s sold to us: to replace steel and concrete and brick in order to lower the amount of embedded energy spent in the building materials. Too bad the material won’t last, so you end up using more in replacing it every few years – or you only use it in places where it can last, which isn’t very many.
Where is this town you live where no wood is used in new construction?
You must live in a very urban area. Wooden ties are still used in abundance.
Heh, made for the centuries indeed.
https://youtu.be/YE-Oa7mAyDU
Concrete has a finite and surprisingly limited lifespan when rebar or tensioning is involved, which is the vast majority of the cases in modern architecture. You’re looking at about 50-100 years when applied correctly and less when mistakes are made, which is frustratingly common.
Yes, and many building regulations require reinforcement for safety, even in situations where the load is nearly always compressive (eg foundations). It’s unfortunate that steel remains the cheapest way of achieving that. We are destined to replace concrete bridges every 40-70 years until we find cost-competitive non-rusting alternatives. Traditional teachings led us to believe that steel didn’t need anti-corrosive coatings within concrete because the alkaline nature of concrete prevented corrosion. That is true, right until micro-fractures caused by repetitive load cycling allow moisture in. Every seaboard city in the US contains concrete infrastructure that is testament to this. I could bore you with 3 examples of visible rebar within a mile of me right now. When rebar rusts, it expands, and blows out the surrounding concrete.
My garage has glass microfiber-reinforced concrete in its floor, and my (wood-framed) walls are clad in cellulose fiber-reinforced cement (HardiePlank). Neither see significant tension loading such as a structural beam would though, and both are micro-reinforcement. We need a macro-reinforcement that is easy to use on-site. I wonder if ultra-high molecular-weight polyethylene rope and netting could be the future here, or perhaps aramids (eg Kevlar).
Without steel, concrete can last millennia. Roman examples of concrete construction survive to this day.
9 out of 10 million smoky flavored corpses disagree.
There are historical reasons for not building cities or other crowded developments out of wood. Sequestering carbon is a poor argument when it’s guaranteed there will be an eventual massive and tragic release. Fire prevention systems fail due to poor maintenance. Chemical retardants cannot foresee the unknown myriad substances they will be subjected to over the course of human habitation and may end up chemically asphyxiating a population instead, or causing birth defects, cancer or other medical issues.
Wood can be beautiful and warm, it’s a romantic vision, this sylvan city, but the permanence of ancient stone cities cries out witness to it’s folly.
Nothing looks looks cheaper or more like accelerated garbage than current steel and concrete construction blight our countryside. Best practice timber framing lasts hundreds of years and the materials are almost infinitely recyclable and reused into other products. Also a bit of science is in order. Wood shrinks into it self as it dries. It does not crush windows and doors if built properly and the force would be gravity
Wood requires maintenance, mostly to keep it dry. Paint or stain external wood surfaces, or impregnate them with anti-rot compounds like copper naphthanate. Keep the roof watertight or the timbers supporting it will rot. Beware of holes in external walls.
I have some photos of 8×8 lumber in my house rotted more than half way through. Water got through gaps in the plank-and-strip exterior wall, and over time the sill plate was nearly destroyed.
Best practices timer framing can last hundreds of years, but those buildings were made when it was common to have a big roaring fire in the middle of the house and the wind howled though holes between floorboards. As long as the house was kept warm by spending tremendous amounts of energy, it would keep dry and free of rot.
Wood construction combined with modern bottle houses where moisture condenses within the walls because the heat and air leaks are minimized for high-efficiency heating; the structures are covered in plastic tarp to prevent it from happening, but the plastic has a limited lifespan and eventually crumbles, develops leaks, and then the walls start rotting around you. 40 years max and the house is ready to demolish.
They have changed building codes many places in the last 10 years, for minimum air exchange, gaps under doors for circulation etc.
The membranes now in use are not just plastic sheeting, but are breathable.
The environmental soundness of wood is negated by the maintenance requirements. Concrete is fire and forget – you pour it once, and then it lasts for a century without you doing anything to it – whereas wood requires repairs every couple decades. Wooden buildings are “live”, they change shape with temperature and humidity, so all the joints move and forces build up gradually. Wood cracks and warps when it’s too dry, it swells up when it’s humid, and all this mechanical action eventually breaks it down structurally. Beams will de-laminate, nails will get pushed out, bolts will loosen… and the infrastructure isn’t getting enough money for maintenance as it is.
Glued lamination attempts to solve these issues by cross-laminating wood, but it only really works in environmentally controlled spaces like the interior spans of buildings. Outdoors, it gets attacked by the elements and breaks down rapidly.
“concrete increases tensile strength” MMMM, I do not think so. Concrete has large compression strength, not tensile. Just ask the nice people that were on and under the bridge in Genova…
WTF do you think we engineers are built for?
https://www.theguardian.com/cities/2018/feb/16/plyscraper-city-tokyo-tower-wood-w350
I don’t want to sound offensive, but the first paragraph is full of factual errors. Having said that, the entire article sounds like a brochure advertising wood buildings.
“concrete increases tensile strength” Stopped reading, right there. Go back to school.
Some of the comments are as bad as the article. Just so you know, I was a professional structural engineer once upon a time (long retired)
Wood is an excellent material to work with. There are wooden buildings that are almost a thousand years old ( a church in Finland is over 900, though I forget the location). The environment within a building tends to be fairly stable over time if the building is in continuous use, so hot/cold/humid/dry is not a major issue. Don’t forget there are trees that are several thousand years old (bristle cone pines and such).
When I first studied fire safety in university, the professor showed a photo of a building that was built in the late Victorian era. It had suffered a massive fire in the ’60s and had been built with timber columns supporting steel beams. The columns – over a foot square in section, were heavily charred on the outside but still retained most of their structural strength. The steel beams softened in the heat and were bent like wet spaghetti and couldn’t even support their own weight. Massive wood structural elements burn _slowly_ even without fire retardants while steel has to be insulated to resist fire. The fire resistance in a structure only has to be there till the fire can be put out, not an eternity.
Wood can and does check, warp and so on. However, that is included in the design specs in building codes. Since these are knows characteristics of wood, load ratings and construction techniques take this into account.
Wood needs some maintenance, yes. So do concrete and steel. Concrete cracks under tension and exposes the rebar. Corrosion of the rebar can occur at that point – this will cause spalling – a serious concern in concrete used outdoors in environments where salt is a problem though it can be an issue in buildings.
Leave wood construction to the experts, not the internet know-it-alls.
But how do the wooden columns compare to steel of the same volume and shape? What if you then reduce the diameter of the steel so that it has the same weight per length as the wood? And did the (I guess horizontal) steel beams experience the same amount of heat as the vertical wooden columns?
> There are wooden buildings that are almost a thousand years old ( a church in Finland is over 900, though I forget the location).
No such thing exists. The oldest wooden church in Finland that I can find records of was made in 1626.
The churches tend to be made of stone, with wooden roofs which were regularly rebuilt. The Russian Orthodox church has a habit of building wooden churches which can be very old, but they too are maintained and rebuilt continuously. Especially the tarred roof shingles have a lifespan of only a few years. They’re also the reason why these churches tend to burn down regularly.
The oldest wooden structure still standing, at least in part, may be the Greensted Church in England:
https://upload.wikimedia.org/wikipedia/commons/b/b5/Greensted_Church_North_Side.jpg
Some bits of it date to the 11th century, though most of it has been restored and rebuilt over and over.
Another reason why there can’t be 900 year old churches in Finland is because it became Christianized when the Swedes invaded the place around 1250.
Ah! But during the Winter in Finland, the days are much shorter, so they can cram in many more years than people living farther south!
– Decommissioning: If we’re going to build with wood, we need a better solution to poisoning wood than we currently use. Such that it can be soaked out using another chemical (not water) that produces a solution that is neutral/non-toxic that can be washed out by water. Otherwise, the material is only safe in a designated landfill, which is unkind to the future.
– Resilience: an issue with glulam and other glued products is that the outer surface is wood, and has to be covered with yet another toxic product, requiring more labour (whereas concrete is generally ready to stand the elements as is). Again, another advance in chemistry is required. Otherwise, the wood is still unsafe for the future.
– Burning: pretty obvious that consuming energy to build the panels now, and then burning them is just cheating, pushing the carbon debt into the future.
– Flexibility: just as we were breaking out of the confines of flat surface drafting towards more plastic shapes created from steel, we’re dropping ourselves right back into flat-pack limits. I’m quickly getting sick of fake-origami shapes. We’ll need new construction techniques to bring glulam to the field, or at the very least, a local shaper.
– Longevity: Using wood or fossil fuels to extract stone has proven to have longevity (Romans, Renaisssance, etc.) but the design industry is no longer designing for permanence. We design for our own uniqueness rather than ideals beyond our lifetime. But there isn’t enough fuel for our egos.
– Rapidity: finding new chemistry, testing it by competition and in-field, and getting it accepted by builders (or the owners of builder robots) will take 50 years or more to only start to happen in some countries.
– Roads/Highways: the largest use of concrete and steel is the highways (not sure if that is every year, or sporadic) but it still is a travesty in that it is a massive carbon use for a cars which are highly liberating but energy inefficient from start to finish of the concept (car production, road production, bridge production, parking production, city travel distances, fuel consumption). Automated cars in 5 years could drive on narrow tracks, passing at designated locations. Better yet, invent better mass transport and last mile(s) services, including the moving of cargo (not just people).
– Quantity: wood construction used to last due to tighter grain woods being available. Everything is pine now. Which is pretty much the west’s equivalent of bamboo. Relatively quickly growing, straight, low quality….grass? But building in wood is going to require a lot more trees that grow …quicker. We need to genetically modify trees — maybe even better than pine finally… — to grow Much faster. There’s been some work in this area, but it needs to ramp up a lot more than just 8 percent. Imagine oak trees growing straight to maturity in 8 years. Or even artificial wood grown in vats. Why not (we’re already producing skin and muscle — albeit still tasteless — in vats…)
– Energy: there’s been work at making concrete with less energy. That actually makes a lot of sense (it’s not the concrete that is the issue — it’s the energy consumed making it). And if that can be done, can the way we make glass and steel be re-imagined to consume a lot less? There’s a better chance of the market forcing a hundred factories to reinvest in new equipment than a quarter billion builders around the world to change the materials, tools, skills they use to build. Unless we’re talking about robot builders.
– Consumers: the elephant in the room is that there are too many consumers for the resources available. If the subject is carbon release, and not limited to decorating the problem with a wood cherry, the most expedient way to decrease that number and cut our consumption is have no more than 1 kid. Without a change in the way we finance the old (by taxing the young), this will cause a deficit, raise immigration and change demographics. But are that artificially racist and nationalistic and small minded that we are willing to sacrifice a planet to fuel our illusions of permanency? It might be uncomfortable for some…but it will be less uncomfortable than a permanent hike in temperature, wild fires (in forests like Australia and now cities made of wood made toxic…), less water available due to the heat, etc. Probably lost 80% of you on this point. Apologies for that.
It is also the concrete that is the issue, the huge majority of concrete today needs processing of limestone to lime. Now limestone is a calcium carbonate, carbon sequestered by aquatic organisms over millions of year, and whether you heat it by fossil fuels, solar furnace or pixie dust it releases that fossilised carbon as CO2.
Thanks for the information. Good point on concrete. Might consider using other materials developed in part by nature and less heat:
https://www.weforum.org/agenda/2018/05/supermud-bricks-could-help-tackle-the-world-s-housing-crisis-and-cut-carbon-emissions-that-cause-climate-change
The folly of intentionally committing a demographic suicide is that you will be replaced by people who don’t share your values, so they have no need to commit to your purposes and in all likelyhood will make even more babies.
> Automated cars in 5 years
How about 50. It takes 20 years just to replace the current fleet of cars if you started exactly now.
The folly is worth it. Their Values may actually be more Valuable, with a sense of Sustainability, Community, Continuity — rather than Uniqueness, etc.
Just a thought.
The sky is falling and we need population control?
Yes, so fewer people get hit by sky chunks!
The currently highest “wood building” is in Vienna (24 stories, 84 m):
http://www.hoho-wien.at
It uses a “hybrid” building technology. From the website:
“Thanks to innovative wood technology, roughly 75 percent of the building from the ground floor up will be made of wood; the service core will be constructed of solid reinforced concrete to which the timber supporting structure is secured.”
I’m not sure if it really counts as wooden building, but on the other hand I’m also not sure where the threshold would be :).
In my opinion it doesn’t look look shabby or fragile. The website has a lot of information about the design. What is missing are some real pictures. Some can be found here: https://www.woschitzgroup.com/en/projekte/hoho-vienna-wooden-tower/
That concrete “core” seen in one of the pictures is a pretty big chunk of it – yeah, I would hesitate to call it a wood building.
I’m just guessing, but elevator and fire escape stairwells need to be isolated (such as by concrete and steel doors) from the rest of the structure.
So when a crew knocks down a wooden skyscraper,
will they yell; TIMBERRRRR!
?
I’m pretty sure they would not be able to resist.
Build a skyscraper out of wood? Edward Woodward would.
I am a carpenter and unfortunately nowadays have to use many “altered” products CLT is harmless when compared to other chemically treated products such as decking CCA I’ll let you Google that one,timber buildings built correctly have a huge life span,risk of fire is present in all buildings,Grenfell Tower London wasn’t wooden but the fire was horrific,I think the article itself was attempting (badly)to point out environmental benefits from getting away from concrete builds, unfortunately the article was so badly written any message was lost,and as above open to ridicule
Sounds TOXIC in other ways through the treatment
Meh, some UK guys worked out a new and more efficient way to make titanium, combine that with cheap electricity from fusion reactors and in 20 years or so from now structures could be made from titanium and artificial sapphire for the transparent parts. Structural colour on titanium can be done with lasers too, so colourful buildings that never need repainting. Wood is a fad but ultimately our open spaces need to be returned to wilderness as soon as we no longer need them for food and material production, just to maximise biodiversity and allow evolution to progress reasonably naturally. Forget climate change that is just delusional mania, a confected distraction from what the future really holds, some robot is more likely to do you in before the climate has a chance to change enough for you to actually notice with your own senses.
But Mr. Scott prefers transparent alumin[i]um in the 23rd Century!
The only reason I’m not convinced that particle board was invented in the darkest fiery depths of Hell to torment mankind by falling apart shortly after installation is that it isn’t fireproof.
It’s fantastic to learn that advanced timber can be used to build structures with less energy compared to steel. My brother is wanting to become an architect and he was wondering what kind of material he could use that would be eco-friendly. I’ll be sure to tell him that he should learn about advanced timber for his buildings.