6 ms·

I don't know if it is really a problem, more like a tradeoff. Reinforced concrete costs less and enables shapes that are impossible without it, with the downsid

by idoh 5y ago

I don't know if it is really a problem, more like a tradeoff. Reinforced concrete costs less and enables shapes that are impossible without it, with the downside that the buildings last 50 years instead of 100+ years. The present value of a building that lasts 50 years is not that much different that the same one that lasts 100 years. With that in mind, it makes perfect sense to make an office building out of reinforced concrete.

nerdponx 5y ago
> The present value of a building that lasts 50 years is not that much different that the same one that lasts 100 years. That's a problem in and of itself, IMO. Construction is tremendously resource-intensive. We should not be building "throwaway" buildings.
- cle 5y ago
  Not so straightforward. Sometimes we throw things away to make room for better things.
- idoh 5y ago
  A - The concept of present value isn't a problem, it's more like a fact, derived from the time value of money. It's like saying gravity is a problem. B - Construction is resource intensive, no doubt about it. Without this technique the costs and resources would go up, double?, more? Many structures we take for granted, like freeway overpasses, would be impossibly expensive.
- renewiltord 5y ago
  The classic problem is similar to that of that other famous future-proof thing: wifi in hotels. All the fancy hotels that got high-end wifi in the 2000s had shitty Internet for a long time because it was too hard to redo. Sometimes, building to throw away is the best model. If something is so resource intensive in a way where the externalities are not appropriately mitigated, the right way is to tax the externalities, not to go after specific things. If these builds were too expensive to build, they wouldn't be built.
  - jandrese 5y ago
    Although the hotels that hardwired RJ45 to each room are still going strong.
    - renewiltord 5y ago
      Right, they can stick APs in them. The point is that back then no one knew which tech would win and what tradeoff to make. Agility beats everything else except "guessing right".
      - oasisbob 5y ago
        For large institutions in the early 2000s, it was very obvious that Category 5 wiring and Ethernet was a difficult technology to beat. Even back then, most universities were running Ethernet to rooms in all new construction, and retrofitting spaces without it. That infrastructure is still useful, 20 years on. It isn't about agility or guessing right, it's about piloting attractive technologies (eg, small-scale DSL which uses existing phonelines, which was oftentimes a reliability nightmare), and keeping an eye to the future.
- hackeraccount 5y ago
  That's a bit like the one horse shay. It's not how long it lasts but what are the costs associated with it lasting any given length of time. Nothing lasts forever but say buildings lasted 500 years - Suddenly 500 years from now all buildings have to be replaced? And what's the cost of this 500 year building? Is it 10 times as much? Or is it 5 times as much? Saying we shouldn't have buildings that only last 50 years but rather they should last 500 is like saying they shouldn't last 50 years but instead 5. Maybe. Maybe 5 makes sense. My assumption would be - shocker - it's probably a complicated trade off that's best adjudicated by the people with the most skin in the particular game.
  - lovemenot 5y ago
    I understand your reasoning. The problem is that this line is seldom used in the opposite direction. You want a flimsy shell and to externalise the environmental impact? Sure thing, whatever the market will bear and is legal. I think it is fair enough for people to put pressure on current practices. Zara and H&M will persist, but their customers should be and, thanks to outside voices, are now aware that social and environmental factors are involved in fast fashion. Sure, it's arbitrary. But we still have alternatives. All else being equal, less entropy is better than more.
  - Dylan16807 5y ago
    > Suddenly 500 years from now all buildings have to be replaced? And what's the cost of this 500 year building? Is it 10 times as much? Or is it 5 times as much? What a weird argument. It's obvious for multiple reasons that all buildings won't fail at the same time.
- majormajor 5y ago
  > That's a problem in and of itself, IMO. Construction is tremendously resource-intensive. We should not be building "throwaway" buildings. If population levels change, up or down, we are going to have to be continually adjusting our usage of space to account for this. Making it easier to modify and/or tear-down-and-rebuild would make things a lot more efficient there. You'd need some policy changes too to fix the problems of, say, homeless people sleeping outside empty office buildings, but getting construction costs down would be a huge part of this. We shouldn't be so arrogant to assume we are planning the right construction to serve us well for hundreds of years.
- dylan604 5y ago
  If the buildings last a shorter amount of time, then more construction is needed which provides jobs. /s
dwighttk 5y ago
“This is going to last 1000 years!” … “It only lasted 50” … “I don’t know if it is really a problem…”
raylad 5y ago
It will become a very big problem if/when buildings start collapsing with people in them. I grew up partly in an 18 story reinforced concrete building built in the 1920s. The apartment I lived in was recently sold for several million dollars. Once, when there was a leak and the plaster came off, the underlying concrete was exposed and it scraped away like very weak sandstone. How strong is the building and when will it collapse? Does anyone know? Is anyone testing? I think the answer to both of those questions is "no". Everyone seems to assume they will stand forever. They won't.
- diegocg 5y ago
  Unless you are living in a developing country, the answer to the second question should be "yes".
  - raylad 5y ago
    It should be but is it? I don't think anyone ever tested this building, which has a combined market value of probably close to $200M. None of the owners want to know that their investments are worthless. So nothing will be checked unless its required by law.
    - diegocg 5y ago
      In Spain buildings older than 50 years are required to be inspected and mandated to make reforms if necessary. I doubt it's much different in the rest of Europe/north America Also, buildings don't fall all of sudden. You would get a lot of cracks and problems before your building collapses
      - robocat 5y ago
        > Also, buildings don't [fail] all of sudden They certainly do in earthquakes. Even in areas that nominally don’t have earthquakes, some parts of the building code will surely be about ability to withstand a rare earthquake.
      - dredmorbius 5y ago
foolmeonce 5y ago
Having 1 in 25 buildings being completely rebuilt at all times and another 1 in ~5 getting renovations is extremely annoying. I think buildings that are too regularly under construction should carry some tax penalties, instead renovating non-durable buildings to tastelessness is a way to save on property taxes, get tax deductions and try to pressure tenants out to get the latest upscale rates.
- woah 5y ago
  Huh?
GoToRO 5y ago
I spoke with a builder, and the concrete starts to decay in 50 years. Until then it's like new. It lasts much longer than that, 100+ years is not a problem.
- wonder_er 5y ago
  I suggest the builder may have suffered from some motivated reasoning. Concrete not starting to decay until 50 years has passed is the exception, not the rule.
  - gamblor956 5y ago
    Only if you have poorly mixed concrete. The kind of concrete they use in buildings is not the same as the concrete they use in sidewalks.
- barrkel 5y ago
  The problem, as per the article, isn't concrete. It's rusting steel inside reinforced concrete.
- oxfeed65261 5y ago
  To be clear, the article is discussing reinforced concrete—concrete made with steel rebar, which rusts. Unreinforced concrete can and does last for many hundred years. Reinforced concrete, not so much. FTA: “Early 20th-century engineers thought reinforced concrete structures would last a very long time – perhaps 1,000 years. In reality, their life span is more like 50-100 years, and sometimes less. Building codes and policies generally require buildings to survive for several decades, but deterioration can begin in as little as 10 years.”
  - GoToRO 5y ago
    We only use reinforced concrete. The type of work where simple concrete is enough are very rare.
    - labawi 5y ago
rsj_hn 5y ago
With 30 year fixed rate mortgages at 3%, I'd say the present value of a building that lasts 100 years is 23% more than the present value of a building that lasts 50 years. It's certainly worth it to spend more for a longer lasting building.

by idoh 5y ago

nerdponx 5y ago

> The present value of a building that lasts 50 years is not that much different that the same one that lasts 100 years. That's a problem in and of itself, IMO. Construction is tremendously resource-intensive. We should not be building "throwaway" buildings.

cle 5y ago
Not so straightforward. Sometimes we throw things away to make room for better things.
idoh 5y ago
A - The concept of present value isn't a problem, it's more like a fact, derived from the time value of money. It's like saying gravity is a problem. B - Construction is resource intensive, no doubt about it. Without this technique the costs and resources would go up, double?, more? Many structures we take for granted, like freeway overpasses, would be impossibly expensive.
renewiltord 5y ago
The classic problem is similar to that of that other famous future-proof thing: wifi in hotels. All the fancy hotels that got high-end wifi in the 2000s had shitty Internet for a long time because it was too hard to redo. Sometimes, building to throw away is the best model. If something is so resource intensive in a way where the externalities are not appropriately mitigated, the right way is to tax the externalities, not to go after specific things. If these builds were too expensive to build, they wouldn't be built.
- jandrese 5y ago
  Although the hotels that hardwired RJ45 to each room are still going strong.
  - renewiltord 5y ago
    Right, they can stick APs in them. The point is that back then no one knew which tech would win and what tradeoff to make. Agility beats everything else except "guessing right".
    - oasisbob 5y ago
      For large institutions in the early 2000s, it was very obvious that Category 5 wiring and Ethernet was a difficult technology to beat. Even back then, most universities were running Ethernet to rooms in all new construction, and retrofitting spaces without it. That infrastructure is still useful, 20 years on. It isn't about agility or guessing right, it's about piloting attractive technologies (eg, small-scale DSL which uses existing phonelines, which was oftentimes a reliability nightmare), and keeping an eye to the future.
hackeraccount 5y ago
That's a bit like the one horse shay. It's not how long it lasts but what are the costs associated with it lasting any given length of time. Nothing lasts forever but say buildings lasted 500 years - Suddenly 500 years from now all buildings have to be replaced? And what's the cost of this 500 year building? Is it 10 times as much? Or is it 5 times as much? Saying we shouldn't have buildings that only last 50 years but rather they should last 500 is like saying they shouldn't last 50 years but instead 5. Maybe. Maybe 5 makes sense. My assumption would be - shocker - it's probably a complicated trade off that's best adjudicated by the people with the most skin in the particular game.
- lovemenot 5y ago
  I understand your reasoning. The problem is that this line is seldom used in the opposite direction. You want a flimsy shell and to externalise the environmental impact? Sure thing, whatever the market will bear and is legal. I think it is fair enough for people to put pressure on current practices. Zara and H&M will persist, but their customers should be and, thanks to outside voices, are now aware that social and environmental factors are involved in fast fashion. Sure, it's arbitrary. But we still have alternatives. All else being equal, less entropy is better than more.
- Dylan16807 5y ago
  > Suddenly 500 years from now all buildings have to be replaced? And what's the cost of this 500 year building? Is it 10 times as much? Or is it 5 times as much? What a weird argument. It's obvious for multiple reasons that all buildings won't fail at the same time.
majormajor 5y ago
> That's a problem in and of itself, IMO. Construction is tremendously resource-intensive. We should not be building "throwaway" buildings. If population levels change, up or down, we are going to have to be continually adjusting our usage of space to account for this. Making it easier to modify and/or tear-down-and-rebuild would make things a lot more efficient there. You'd need some policy changes too to fix the problems of, say, homeless people sleeping outside empty office buildings, but getting construction costs down would be a huge part of this. We shouldn't be so arrogant to assume we are planning the right construction to serve us well for hundreds of years.
dylan604 5y ago
If the buildings last a shorter amount of time, then more construction is needed which provides jobs. /s

dwighttk 5y ago

“This is going to last 1000 years!” … “It only lasted 50” … “I don’t know if it is really a problem…”

raylad 5y ago

It will become a very big problem if/when buildings start collapsing with people in them. I grew up partly in an 18 story reinforced concrete building built in the 1920s. The apartment I lived in was recently sold for several million dollars. Once, when there was a leak and the plaster came off, the underlying concrete was exposed and it scraped away like very weak sandstone. How strong is the building and when will it collapse? Does anyone know? Is anyone testing? I think the answer to both of those questions is "no". Everyone seems to assume they will stand forever. They won't.

diegocg 5y ago
Unless you are living in a developing country, the answer to the second question should be "yes".
- raylad 5y ago
  It should be but is it? I don't think anyone ever tested this building, which has a combined market value of probably close to $200M. None of the owners want to know that their investments are worthless. So nothing will be checked unless its required by law.
  - diegocg 5y ago
    In Spain buildings older than 50 years are required to be inspected and mandated to make reforms if necessary. I doubt it's much different in the rest of Europe/north America Also, buildings don't fall all of sudden. You would get a lot of cracks and problems before your building collapses
    - robocat 5y ago
      > Also, buildings don't [fail] all of sudden They certainly do in earthquakes. Even in areas that nominally don’t have earthquakes, some parts of the building code will surely be about ability to withstand a rare earthquake.
    - dredmorbius 5y ago

foolmeonce 5y ago

Having 1 in 25 buildings being completely rebuilt at all times and another 1 in ~5 getting renovations is extremely annoying. I think buildings that are too regularly under construction should carry some tax penalties, instead renovating non-durable buildings to tastelessness is a way to save on property taxes, get tax deductions and try to pressure tenants out to get the latest upscale rates.

woah 5y ago
Huh?

GoToRO 5y ago

I spoke with a builder, and the concrete starts to decay in 50 years. Until then it's like new. It lasts much longer than that, 100+ years is not a problem.

wonder_er 5y ago
I suggest the builder may have suffered from some motivated reasoning. Concrete not starting to decay until 50 years has passed is the exception, not the rule.
- gamblor956 5y ago
  Only if you have poorly mixed concrete. The kind of concrete they use in buildings is not the same as the concrete they use in sidewalks.
barrkel 5y ago
The problem, as per the article, isn't concrete. It's rusting steel inside reinforced concrete.
oxfeed65261 5y ago
To be clear, the article is discussing reinforced concrete—concrete made with steel rebar, which rusts. Unreinforced concrete can and does last for many hundred years. Reinforced concrete, not so much. FTA: “Early 20th-century engineers thought reinforced concrete structures would last a very long time – perhaps 1,000 years. In reality, their life span is more like 50-100 years, and sometimes less. Building codes and policies generally require buildings to survive for several decades, but deterioration can begin in as little as 10 years.”
- GoToRO 5y ago
  We only use reinforced concrete. The type of work where simple concrete is enough are very rare.
  - labawi 5y ago

rsj_hn 5y ago

With 30 year fixed rate mortgages at 3%, I'd say the present value of a building that lasts 100 years is 23% more than the present value of a building that lasts 50 years. It's certainly worth it to spend more for a longer lasting building.