from the people-in-wood-skyscrapers-shouldn't-throw-woodpeckers dept.
Arthur T Knackerbracket has processed the following story:
A report by Knowable Magazine provides a rather insightful glimpse into the rise of mass timber and its benefits. The technique basically uses massive engineered wood elements instead of concrete and steel to build higher than ever before. As of 2024, mass timber buildings have climbed to almost unbelievable heights, with the 25-story Ascent tower in Milwaukee leading the pack.
The building is far from the only one in the category. The report states that there were 84 completed or under-construction mass timber buildings of eight stories or higher worldwide by 2022, with another 55 proposed. Europe dominates with 70% of these, but North America is catching up with around 20%.
As for what's driving this wooden renaissance, there are multiple reasons. For starters, mass timber could be an answer for reducing concrete and steel's massive carbon footprint, which alone makes up a whopping 15% of global emissions.
[...] But what about issues like raw strength and fire resistance, which have historically held wooden buildings back? Well, mass timber uses elements like cross-laminated timber (CLT) panels that can match steel's strength pound-for-pound, thanks to layering and high-pressure gluing techniques.
Modern mass timber also passes rigorous fire testing. In the event of a fire, a protective char layer forms on the wood's surface, insulating the interior from flames long enough for evacuation and firefighter response.
Likely taking these perks into account, a 2021 update to the International Building Code gave mass timber a huge vote of confidence, allowing such constructions up to 18 stories in many places.
Of course, moisture poses risks that need careful management to prevent fungus and pests. But proponents are confident mass timber can be a sustainable solution if done right.
(Score: 5, Informative) by pTamok on Wednesday October 23, @11:28AM (3 children)
"Well, mass timber uses elements like cross-laminated timber (CLT) panels that can match steel's strength pound-for-pound, thanks to layering and high-pressure gluing techniques."
Pound-for-pound, maybe. Pint-for-pint, no. Steel is significantly denser than wood, so for the same structural strength, requires a smaller volume. When you are selling real-estate, the extra structural volume is lost floor-area, and therefore, lost income.
I've also seen engineered wood described as resin with some cellulose in it. Many resins are not exactly environmentally friendly, and the stuff some outgas may not be particularly good for the building's users.
I'll admit that engineered wood looks really nice, so in terms of the look of the built environment, I prefer wood rather than concrete and steel.
(Score: 3, Informative) by VLM on Wednesday October 23, @12:13PM (2 children)
How about for the same structural rigidity?
A wood building that carries the same weight as a steel building will sway more, I think. I would have to check that out to be certain.
Regardless of which is more floppy, there are a lot of finishes in buildings that might not be possible to rigidly attach to the wood structure due to sway and thermal expansion being different from steel. Imagine windows in the facade cracking in the winter when humidity is low and the wood shrinks.
(Score: 4, Informative) by khallow on Wednesday October 23, @12:25PM
Rigidity typically goes up as the fourth power of thickness - at least till it nears breaking point. That alleged higher volume will translate into thicker structural members.
(Score: 0) by Anonymous Coward on Thursday October 24, @03:25AM
> Imagine windows in the facade cracking in the winter when humidity is low and the wood shrinks.
No need to imagine, just look to IM Pei's John Hancock Tower: https://en.wikipedia.org/wiki/John_Hancock_Tower#Engineering_flaws [wikipedia.org]
This was no joke, I was in Boston at the time and someone at my uni grabbed a piece of the blue glass and posted it on a cork board with thumbtacks. I guess as a reminder to listen to your engineers.
(Score: 3, Interesting) by VLM on Wednesday October 23, @12:09PM (9 children)
How about maintenance? You can weld steel. Reinforced concrete is a MUCH bigger problem but at least you can cast replacements in place. The replacement process for wood is... One guess I immediately came up with is replace wood with steel beams. If you have the engineering drawings, and a steel solution always takes up less volume than wood, then replacing rotted burned or otherwise damaged wood should be simple with a steel cutting/welding torch.
Another question I have is its assumed in residential construction that the tradies will randomly cut and drill wood and a fair amount of that is written into the building code. None the less you'll occasionally see plumbers cut beams entirely in half. I would imagine workplace rules must be interesting at wood skyscrapers to stop electricians from sawing entire columns in half etc.
(Score: 2) by aafcac on Wednesday October 23, @02:16PM (5 children)
You can replace one or two of them at a time, as long as you're on top of it and find a problem when there's not too many, that's really not a problem to replace one due to the extra ones that are installed to begin in case things like that or miscalculations are made.
(Score: 2) by VLM on Wednesday October 23, @04:21PM (4 children)
That makes sense. I was thinking like a fine woodworker where its a game to try and design something like a desk with super crazy wood jointery such that the entire desk can only be assembled around a shelf divider, however, for buildings, I imagine timber framers would look down on behavior like that and prefer to make parts replaceable.
(Score: 2) by aafcac on Wednesday October 23, @07:48PM (3 children)
A lot of it comes down to how it's been designed. It's going to be a lot easier on smaller buildings, but if you're using wood for something like this, there's going to be some consideration made for what happens if you start to get rot or decay. But, typically the stresses tend to route around things like that, so long as you don't remove too many of the supports all at once. There's generally some consideration paid to how to shore things up to replace one or another.
That being said, wood lasts for quite a long time as long as it's kept dry and protected from insects.
(Score: 2) by Reziac on Thursday October 24, @02:27AM (2 children)
And that was my first thought: termites.
Ground termites are why there are very few old wooden buildings in the SoCal desert (the fact that it's extremely dry notwithstanding). However, when they swarm, they also fly, and get into windowframes and such that way.I had 'em travel under ten feet of slab and come up in the pantry, in a bag of flour!
And there is no Alkibiades to come back and save us from ourselves.
(Score: 2) by aafcac on Thursday October 24, @01:44PM (1 child)
Presumably, the wood can be treated with something that keeps them at bay, but I also think that it may turn out that the technology isn't suitable for some areas. Which would still be fine, not every technology needs to be used every where to still be better having it than not.
(Score: 2) by Reziac on Friday October 25, @06:27AM
Treatment will keep termites at bay.
And Termidor around the foundations.
For a while.
And there is no Alkibiades to come back and save us from ourselves.
(Score: 0) by Anonymous Coward on Thursday October 24, @01:00AM (2 children)
There were lots of wooden ships in the past and people managed to maintain those. I'm sure some can figure it out in 2024.
https://en.wikipedia.org/wiki/List_of_longest_wooden_ships [wikipedia.org]
(Score: 2) by tangomargarine on Thursday October 24, @05:05PM (1 child)
What does the length of the ship have to do with anything? The whole thing with skyscrapers is they're very tall, which means much more weight on a smaller base. I want to say sailing ships were mostly the equivalent of only 1 or 2 stories tall.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 2) by Reziac on Friday October 25, @06:31AM
I'm thinkin' the first fire that punches through a floor or into a maintenance shaft will put the kobosh on the whole concept. Cuz it's gonna chimney really fast, and no amount of fire retardant will stop that.
And wooden ships take a shitload of maintenance.
And there is no Alkibiades to come back and save us from ourselves.
(Score: 2) by PiMuNu on Wednesday October 23, @12:39PM (3 children)
An FA:
"An official report into the collapse of a 10-year-old mass-timber bridge in Norway in August 2022 has criticised the structure's design and construction.
Two drivers had to be rescued after the Tretten Bridge, over the Gudbrandsdalslågen river in the Øyer area of southern Norway, gave way as a heavy goods vehicle was crossing."
https://www.dezeen.com/2024/04/11/tretten-bridge-collapse-norway-timber/ [dezeen.com]
I recall seeing a great youtube video (if you can cope with the tubes) on analysis of the failure, but I can't find it now...
(Score: 2) by PiMuNu on Wednesday October 23, @01:52PM (2 children)
ps: TL;DR - the reason for the bridge failure was that the wood was only assessed for dry strength and had a RUD when it got wet.
(Score: 1) by pTamok on Wednesday October 23, @04:35PM (1 child)
Was it?
I thought that the issue was that some critical load-bearing joints that were metal pins through holes made in the engineered wood (glulam) were not sized correctly for the stress. I think it ripped apart in fatigue/overload.
https://en.wikipedia.org/wiki/Tretten_Bridge [wikipedia.org]
The Wikipedia article could be wrong, incomplete, or out of date, though.
A linked article in the Wikipedia entry describing the results of a preliminary report issued in December 2022 states:
Now there might have been another report issued, but I've not seen it.
Update. Not sure if the new report adds anything. The linked pages have videos, but the text is Norwegian. Machine translation is your friend.
First report - Issued in 2023 [havarikommisjonen.no]
Second Report - Issued in 2024 [havarikommisjonen.no]
(Score: 2) by PiMuNu on Thursday October 24, @08:24AM
The youtube video was here:
https://www.youtube.com/watch?v=FSPI0xkTifI&t=32s [youtube.com]
I thought the guy said that it was wet vs dry strength but I may be mis-remembering. ps: the video is just a guy on the internet, what do any of us know...
(Score: 3, Touché) by fliptop on Wednesday October 23, @02:15PM (1 child)
And I'll bet Big Timber [youtube.com] is behind it.
Our Constitution was made only for a moral and religious people. It is wholly inadequate to the government of any other.
(Score: 4, Funny) by DannyB on Thursday October 24, @07:51PM
I would have thought Jenga [youtube.com] was behind it.
If a Christmas present has a EULA it should be on the outside of the wrapping paper.
(Score: 2) by Username on Wednesday October 23, @02:56PM (5 children)
Just going up to the 3rd floor in most Victorian era houses is sketchy. I can imagine the 20th floor after only 50 years being so far off you'd think you're drunk.
(Score: 4, Interesting) by Unixnut on Wednesday October 23, @04:11PM (4 children)
To be fair most Victorian houses are from the reign of queen Victoria (1837-1901), meaning the newest "Victorian" house is now 123 years old. If after 120+ years of use those houses with their original wood beams and floorings are still solid enough that not only are those houses habitable, but are actually more desirable than new builds is a positive argument with regards to wood as a building material.
Not to mention that you can find cottages which are older still who have the original wood flooring and roofing. The choice of wood is important for longevity though, and many of the beams I saw were much larger and thicker than equivalent steel I-beams (plus much lower load carrying capacity).
Saying that I am not sure about wood for load bearing walls, especially on high rises. I mean it isn't even real wood they are using but some kind of wood composite using epoxy. Will that epoxy last through the centuries or will it break down? And under what circumstances?
Plus most Victorian houses top out at four floors, and even then the load bearing walls are made of brick, not wood.
Apart from sheds, outhouses and tree houses (all a single floor, max two) I can't think of any long term structure (I do not count temporary installations which were sometimes made of wood) made of wood as a load bearing material that lasted.
(Score: 3, Informative) by VLM on Wednesday October 23, @04:40PM (2 children)
In defense of that opinion, back when they were about half that age the guys on "This Old House" in the 70s were already ripping on Victorians for absolutely nothing about them being square or level.
We have a lot of data from fiberglass boats which have been in commercial mass production since the 1950s in pretty brutal environments compared to inside a building. Supposedly based on accelerated aging testing, post-70s or post-80s epoxy resin fiberglass boats can exceed a hundred years of life out on the ocean. Pre-70s epoxy resin fiberglass may not survive a century in the ocean; maybe only decades. I would think something that survives a century in the ocean could survive a thousand years wrapped up inside a building. One expensive problem is if they screwed up the chemistry you might not find out for fifty years; then what?
https://en.wikipedia.org/wiki/List_of_oldest_extant_buildings [wikipedia.org]
I will concede that the list above is almost entirely made of stone. There are wooden temples in Asia in continuous use for 1500+ years now and 1000+ years elsewhere. There's at least one wood cathedral in Puerto Rico that's been in continuous use for 500+ years. In the USA the wood beams in the Palace of the Governors in Santa Fe have been standing since 1610. I'm sure in Europe a 414 year old building is considered new construction but its the oldest in the USA. Of course 99.9999% of 1500 year old buildings having collapsed is an accurate but pessimistic way to look at it.
(Score: 3, Informative) by Unixnut on Wednesday October 23, @06:17PM
And in defence of the Victorian houses, they may well have been square and level when they were built. The reason for that is that while a house may well have originally been built square and level, the ground underneath them shifts causing the house to move out of square with time, and we are not even talking centuries for this to happen.
Case in point a family member recently bought a relatively new brick house (built 1997) and she was complaining to the builders doing the renovation about the walls and ceiling not being square, how things were bent here or there etc... They flat out told her that with time the foundations shift and even if the building was square when built, after a decade or two it won't be anymore. In fact this is such a known thing that designers actually take this into account (so you don't end up with massive cracks and shears through your walls) and materials are chosen that can flex somewhat for the same reason.
Even ignoring getting the chemistry right, that epoxy is used with fibreglass, not wood. Wood is a different material which is more likely to degrade with time compared to glass (which is inorganic and relatively stable over time). So I don't think we can say that because the epoxy bonded well with glass in harsh environments that the same would apply with wood.
As for getting the building/chemistry right, that is an issue even now. One of the reasons I would not want a new-build house is because a lot of them develop serious faults due to poor quality workmanship after 10 years and within 30 years of being built, while the guarantees only last a max 10 years (sometimes even less).
I guess another reason for preferring old Victorian buildings. If it has been standing solid for 120+ years, chances are it will continue to do so for the next 100 years, because had there been a fault in the workmanship it would have already become clear by now.
However have all those buildings still got the original wood structure? Or has the wood been replaced over time? If over the 1500+ years of existence all the constituent wooden parts of the temple have replaced then we can't say the building as a whole is the same one that was there 1500 years ago. Something we can say for most of the stone buildings on the link you gave.
(Score: 1) by One Time Use on Wednesday October 23, @11:50PM
I lived in a house that was built in the late 1700's. In the basement, you could see the wooden beams with pinned mortise and tenon joints. The cherry newel post for the main staircase was fastened to a under floor beam with wedged through tenons. It was all very solid, but not a square corner, level floor/ceiling, plumb wall, or flat surface anywhere. Many of the windows still had original glass panes with little bubbles and a slightly wavy surface.
(Score: 2, Informative) by pTamok on Wednesday October 23, @04:59PM
Norwegian stave churches [wikipedia.org].
The spires of Church of St Mary and All Saints, Chesterfield, UK and St Mary's Church, Long Sutton, UK are 14th and 13th century respectively and tall ( 49 metres and 69 metres). How much of the height is wooden, I don't know. St Mary's claims to have the tallest wooden spire in Europe.
The Tō-ji Temple pagoda in Japan from 1643 is 54 metres tall. The Sakyamuni Pagoda of Fogong Temple in China, which is at least several hundred years old, and possibly close to 1000, stands over 60 metres tall).
I'm sure there are other examples.
Obviously, these are exceptional structures, but illustrate that properly selected, well cared for wood can last well.
(Score: 0) by Anonymous Coward on Wednesday October 23, @05:29PM (1 child)
My concern for this is what happens when they need to come down. Steel is one of the most recycled materials. Concrete chunks can be re-used in various ways also.
AFAIK, homogeneous wood like 2X4s is usually sent to the landfill upon demolition but could be safely burned or recycled in small non-structural projects. Some of it was even a participant in the hipster reclaimed wood furniture movement of late.
Ply and "glue lam", which is what we're talking about here is problematic from a recycle/reuse standpoint. We're not supposed to burn ply in the wood stove. It could get re-used for small projects too, but I don't think it's quite as desirable. I'm not sure how it breaks down in landfills.
So a few decades or maybe 100 years from now, the generations that come are going to have to figure out what to do with these things. It'd be nice if the adhesive composition were marked on the product so at least we'd know. I don't think that's generally done with ply or glue-lam currently so I don't have a lot of hope. It's going to be "well, we know they used wood and a lot of chemicals in this."
(Score: 1, Touché) by Anonymous Coward on Thursday October 24, @01:04AM
The more of these you use and bury, the more and longer the CO2 is out of the atmosphere.
(Score: 3, Funny) by Tork on Wednesday October 23, @06:13PM
🏳️🌈 Proud Ally 🏳️🌈
(Score: 2) by Gaaark on Wednesday October 23, @08:33PM
I thought one of the problems with wood structures was that during very dry periods, the wood dried out and became much more burnable.
Plus, wood can only be raised so high (heh-heh) because wood is not strong enough to go too high and sky-scrapers were (are) the fashion.
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 4, Insightful) by bzipitidoo on Thursday October 24, @05:15PM
"Engineered wood" is the sort of term that is ripe for abuse. In some cases, "engineered wood" appears to be the new euphemism for particleboard. Particleboard is really crappy stuff. Heavier and weaker than wood, and outgasses toxic chemicals. I hate it. But particleboard is so ubiquitous that avoiding it is difficult. Seems like 9 out of 10 pieces of new wood furniture are made of particleboard. Even desks where they ballyhoo the fact that it is genuine hardwood might have only the top made of hardwood, while the rest is particleboard crap. Furniture made of the stuff is too delicate to easily move.