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The Case for Wooden Skyscrapers
- codesterling 10y agoNo thanks. Steel and concrete don't get termites or burn. So the risk is more, but the benefit is negligible.
- rnl 10y agoThere are no termites in colder climates. The material can be coated to precent any insect from eating it. If you think avout what happened in New York 15 years ago today one might argue steel and concrete burn just as well as wood
- effie 10y agoNeither steel nor concrete burn under ordinary circumstances. Wood does. We do not know what exactly happened in New York, and it does not seem relevant here.
- Normal_gaussian 10y agoYou may have missed them but it is worth pointing out these two tiny sections of the article: > In general, a large mass of wood, such as a CLT floor, is difficult to burn without a sustained heat source—for the same reason that it is hard to light a camp fire when all you have is logs. Once the outside of the timber chars it can prevent the wood inside from igniting. The big urban fires of the past, such as the Great Fire of London, which occurred 350 years ago this month, were mostly fuelled by smaller sections of timber acting as kindling. Prospective tenants would doubtless need lots of reassurance. But with other fire-resistant layers and modern sprinkler systems, tall wooden buildings can exceed existing fire standards > What about woodworm and rot? “If you don’t look after it, steel and concrete will fail just as quickly as timber,” says Michael Ramage, head of the Centre for Natural Material Innovation at the University of Cambridge in Britain.
- codesterling 10y agoYea, I don't buy those as being sound arguments. I'm sorry I don't just accept everything in a sales pitch. I've seen a log cabin burn, and those were 12" logs, so....
- unholythree 10y agoI read the article and I still don't buy it. In New Orleans 1972 a concrete and steel building called the Rault Center had it's top two floors gutted by fire, likely arson. The building has been vacant since then, much of it in an almost skeletal state and yet a renovation started last year. If the Rault Center had sprinklers tragedy could have averted, but I don't believe a wood building could have contained the fire. A wood building certainly couldn't have stood neglected for decades after and still been of any use. http://www.theadvocate.com/new_orleans/news/article_9ca3a457-d492-57a2-80c7-d61fd9ad7375.html http://www.theadvocate.com/new_orleans/news/article_9ca3a457...
- brudgers 10y agoMany contemporary building codes require sprinklers for any building over four stories. To me, the neglect is a sign of economic conditions effecting development more than other factors. For example, if the location was highly desirable and the market for new space strong, redevelopment would make sense.
- gerbal 10y agoYou didn't read the article, did you?
- codesterling 10y agoLower carbon footprint of construction, more expensive, lower noise during construction. I read it, none of those benefits are worth the risks to me.
- gerbal 10y agoThe article directly addresses those risks, asserting that they are not significant.
- blowski 10y agoFrom the guidelines: > Please don't insinuate that someone hasn't read an article.
- scoot 10y agoHighlighting something in an article that shows that a poster clearly hasn't read some or all of the article is "insinuating", and seems to be widely accepted. (And why not - a counter argument based directly on the source material seems perfectly reasonable.) Maybe the guidelines need to change to say not directly call it out, which is what you seem to be objecting to.
- blowski 10y agoSo downvote and say "the article mentions that" with a relevant quote (as per the guidelines). Commenting with "did you read the article?" is just noise.
- scoot 10y agoExactly what I just said. But that is "insinuating", which is what is warned against in the guidelines. Directly calling it out isn;t mentioned. The guidelines are backwards.
- twelvechairs 10y agoThere's a lifecycle issue which isn't accounted for here. Steel and concrete last almost forever once built - how long do you trust your glue-laminated, termite-sprayed, fire-sprayed timber floor? Especially after a couple of cases of water or impact damage over time... Reconstructing towers (particularity residential towers) in-use is an incredibly problematic process.
- Normal_gaussian 10y agoPresumably, having not read any, this is what building codes cover. So in many structures the effect of impact damage would be the same. With water you have more of a point. Reconstructing towers in use seems like a ridiculous thing to add on to the article.
- bryanlarsen 10y agoRoman concrete lasts forever. Modern concrete reinforced with rebar and exposed to the elements lasts about fifty years.
- mcdoh 10y agoIs this just survivorship bias?
- coryrc 10y agoNo, they are chemically different cements. However, Roman cements have a tenth the strength of Portland cements, so we can build much bigger structures now even if they won't last as long.
- pouetpouet 10y agoAlso no rebar, so it means big arches, massive vaulted ceilings, domes etc...
- vlehto 10y agoReinforced concrete suffers from carbonation. The concrete is base, but slowly get's neutralized by carbon dioxide. Once this has been done, the concrete no longer chemically protects the rebar inside. Then if we take into account that most concrete is porous and has moisture content, that rebar is going to rust relatively quickly. When it rusts, it expands breaking away the covering cement. Typically reinforced concrete has lifespan ranging from 60 to 150 years. Wood in colder climates often has similar lifespan. https://en.wikipedia.org/wiki/Concrete_cover https://en.wikipedia.org/wiki/Concrete_cover
- wimagguc 10y agoPrevious discussion on the same topic (different article but might be based on the same press release, the 3D renders are suspiciously similar): https://news.ycombinator.com/item?id=12190537 https://news.ycombinator.com/item?id=12190537 Safety was the first to pop in mind there too -- I guess it won't be easy selling those flats.
- vlehto 10y agoIt's often surprising how much of building codes are about fire safety. Occasional hazards practically define your day to day environment. The most fire sensitive part of a high building is the staircase. You want long burn time in fire but also have very little "fire load". (Amount of energy released from material that can burn in typical fire. Typically MJ/sqm.) Steel staircase gets you 0 fire load but relatively short "burn time". Because steel gets soft at relatively low temperature and more importantly conducts heat very well. Pure concrete stair case is better, but you get cracking that shortens the burn time. Wood is surprizingly good for burn time, but you greatly increase the likelihood that the fire will start form the staircase. Which is really big no-no. Sometimes even burning a complete house (starting from somewhere else) is lot better than just burning the emergency exit. The only really good option is reinforced concrete. The concrete insulates the steel, which provides ductility to the whole structure. With reinforced concrete staircase and stairwell, it's questionable how much you benefit from wooden load bearing structure. I think it can be done. And it can be done really well too. But you may need to step away from typical architecture and step into something more modular.
- Spooky23 10y agoThere's a reason for that. My father in law was a fireman who retired as chief after 45 years. Fires are rare today -- but were incredibly common during the 60s and 70s. He was at an average of two a week in those days. It was common enough that insurance companies had "protectives" who were firemen to go in and pull out your furniture. Fire is rare because of those codes today.
- fpoling 10y agoA highest wooden house is in Bergen, Norway - http://journalofcommerce.com/Projects/News/2016/1/Norwegian-project-breaks-tall-wood-building-record-1013064W/ http://journalofcommerce.com/Projects/News/2016/1/Norwegian-... It is 14 floor apartment building and owners had no problems to sell the apartments there. Personally it looks rather ugly especially when looking from near bridge. But then a lot of modern architecture is ugly for my taste...
- jeff_petersen 10y ago> Personally it looks rather ugly especially when looking from near bridge. But then a lot of modern architecture is ugly for my taste... I agree with you 100% there. That is a particularly ugly building.
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- snthd 10y agoWhat about lightning and seismic zones?
- praptak 10y agoLightning is dealt with by lighting rods. Seismic zones are very non-obvious as factors like eigenfrequency of the building comes into play, not just bare static resistance to stress.
- brudgers 10y agoWood has a particularly good response to bending relative to steel, masonry, and concrete and is likely to perform well relative to other materials during seismic events.
- mhomde 10y agoThere's a really interested building material called CLT (cross-laminated timber) that's exceptionally strong and durable, and has good fire resistant properties. In Sweden some have started building houses out of them since their load bearing qualities enables open floor plans. It's like plywood on steroids and you use giant cutters to assemble buildings in a few large pieces Here's an article, I think there's a few variant of similar materials, not sure which is "best" http://www.popsci.com/article/technology/world%E2%80%99s-most-advanced-building-material-wood http://www.popsci.com/article/technology/world%E2%80%99s-mos...
- arjie 10y agoThere's a building in Portland that's going to be twelve stories tall and built with CLT. My uncle works with one of the companies involved in its construction which is how I heard of it: http://www.structurecraft.com/projects/framework http://www.structurecraft.com/projects/framework
- mhomde 10y agoNice building, looks very Scandinavian/danish to me for some reason :)
- drivingmenuts 10y agoThe one major issue not addressed is: deforestation. Yes, we can make skyscrapers out of wood, but should we? Where do we get the trees from and will they be replaced quickly enough to provide a sustainable future?
- dredmorbius 10y agoThis is getting dinged, but it's a serious concern. There are only so many board-feet (or linear meters) of high-quality timber available in a given year, and construction (and reconstruction) of cities was responsible for deforestation across widespread areas -- San Francisco denuded most of the San Francisco Bay Area, for example. Deforestation in Europe from the 1600s onward had a great deal to do with fuelwood consumption, particularly for glass and iron manufacture. Iron used charcoal, at the rate of about 40-80 kg of source fuelwood per kg of produced iron. Structural wood isn't used at quite the same rate, though it remains a concern, particularly for high-yield-strength. Composite timber (plywood, particle board, and other types) reduces the quality requirements somewhat.
- spodek 10y agoI looked at it the opposite: We can sequester carbon in buildings this way. I haven't done any numbers and presume it's probably small for global warming, but I understand that using concrete put huge amounts of CO2 in the atmosphere, so maybe decreasing that contribution would count for a lot.
- DrPhish 10y agoYou can replace (replant) trees faster than you log them. How are you replacing the steel you're pulling out of the ground? You can recycle steel, but there is a limited supply and extracting it is energy intensive. We can grow an almost unlimited number of trees, and each one is a carbon sink to boot
- Tempest1981 10y agoDoes the soil eventually need to be replenished, and are there any limits on that?
- thr0waway1239 10y agoIf you are reading this thread, you will probably also find the comment thread on the Economist article somewhat informative. (They seem to be moderating it quite well too)