4 ms·

I would like to know more about the long term stability of the glues involved and how the entire structure as a whole decays / fails over what timeframes under

I would like to know more about the long term stability of the glues involved and how the entire structure as a whole decays / fails over what timeframes under what exposures. Most other building materials in use today, the actual core structural elements, have withstood the test of centuries of use and are well proven and stable technologies.

bjelkeman-again 7y ago
There is a lot of good information here: https://www.swedishwood.com/about_wood/about-glulam/ https://www.swedishwood.com/about_wood/about-glulam/
benj111 7y ago
Centuries? Reinforced concrete is 150 years old, steel frame construction a little less so.
- barrkel 7y ago
  Sure, but we have concrete buildings still standing from Roman times - most famously, the Pantheon. I grew up in a cottage a couple of hundred years old, with thick walls built from stone and mortar. It's not unusual to live in a house that's over a century old in Europe. I've also lived in a wooden house - more of a three room + toilet chalet, really. Biggest irritations were all the noises from thermal expansion in the summer, and the fact rats could eat their way in. I think it's a bit more effort to actively maintain wood and be sure it's in good condition than brick and concrete construction. That cottage, btw - the roof had a wood frame, but it wasn't the original - that had burned down along with the thatch at least once, and been replaced some time before we moved in.
  - benj111 7y ago
    If concrete is similar enough to reinforced concrete. Isn't engineered wood similar enough to normal wood?
    - pjc50 7y ago
      Reinforced concrete has different failure modes. The UK built a lot of precast concrete "panel" houses after the war, some of which are disintegrating badly: https://www.peterbarry.co.uk/blog/houses-of-non-traditional-construction-common-property-defects-6/ https://www.peterbarry.co.uk/blog/houses-of-non-traditional-... Another e.g. concrete disintegrating due to use of mine waste: https://www.theguardian.com/money/2009/nov/29/mundic-test-crumbling-concrete-mortgages https://www.theguardian.com/money/2009/nov/29/mundic-test-cr...
      - benj111 7y ago
        Different failure modes, different tensile strength, not really the same at all. That was kind of my point :)
  - willyt 7y ago
    Roman concrete doesn’t have the same chemistry as modern concrete.
    - jabl 7y ago
      And, Roman concrete doesn't have steel rebar which rusts and cracks the concrete.
      - dsfyu404ed 7y ago
        Eh, properly done reinforced concrete should last hundreds of years. Of course it's possible to use the wrong concrete formula for the job (the concrete for your driveway is not the same as the concrete for a boat ramp) but if done right it should last.
    - marmaduke 7y ago
      What’s different? I’m aware of the modern mix with cement sand stone, but I’m guessing romans didn’t have the cement?
      - jbay808 7y ago
        As far as I know, the romans had better cement. We're still trying to reverse engineer it.
        lsc 7y ago
        this is my understanding as well... but I wonder how much of that is that they just had more variable cement, and the stuff that wasn't incredibly great turned to dust long ago? Certainly, our modern processes are more repeatable and produce a narrower range of results. What if the existent buildings are outliers of the roman process?
        jbay808 7y ago
        Attributing the accomplishments of the past to survivor bias is a popular line of thought these days, but... It's unlikely. They used a completely different chemical formula than we do. If you have two processes X and Y, and you observe consistently that Y >> X, and you know that Y and X are produced by different processes so you don't have a strong prior on the mean of Y being similar to the mean of X, then you should conclude it's very likely that the mean of Y is greater than the mean of X. Even if you know for certain that you only have the best samples of Y. But more importantly, we don't really care if the romans also built a bunch of bad buildings using counterfeit cement with a botched formula, that failed to last until today. What matters is that we don't have the technology today that can match their best work. That's what makes it worthy of study.
- anonuser123456 7y ago
  >Reinforced concrete is 150 years old Do you mean steal reinforced concrete lasts 150 years or that the technology is 150 years old? My understanding is that reinforced concrete has a service life of 50 years and 80 years if protected with a sacrificial anode of some sort.
  - benj111 7y ago
    That the technology is 150 years old. https://en.m.wikipedia.org/wiki/Reinforced_concrete https://en.m.wikipedia.org/wiki/Reinforced_concrete
chadcmulligan 7y ago
I had a home in the 90's that had laminated structural beams, I don't live there any more, but last time I drove past it was still standing. I think its pretty common for housing in Australia, here's some info https://www.thefifthestate.com.au/innovation/materials/explainer-everything-you-need-to-know-about-mass-timber/ https://www.thefifthestate.com.au/innovation/materials/expla... Laminated plywood has been used for a long time (70's?), and has been used as cross bracing on timber framed houses. There's also all the sorts of chipboard which although aren't structural are glued. So I suppose there's a fairly long history there with glued timbers. Its the usage as multi storey buildings that is new I guess. Edit: apparently plywood was first made in 1797 https://en.wikipedia.org/wiki/Plywood https://en.wikipedia.org/wiki/Plywood, wow
- jabl 7y ago
  The WWII Mosquito was made from plywood. Some of them sent to the tropics had problems with the moisture weakening the glue. But AFAIK those used different glue than what is used today in plywood production, not to mention 1797.
radicalbyte 7y ago
Timber at least can last a very long time. There are houses in the UK which dates from the time of Shakespeare which are still standing. I'm not sure what's worse: a cheap wooden structure which lasts 50-100 years or a strong brick structure which lasts hundreds. Here in Europe we have a large stock of houses from the 1950's which cost 300 EUR a month to heat and cannot be insulated. For a modern passive house costs are closer to 30 EUR a month.
- Harvey-Specter 7y ago
  Any building can be insulated, you just have to spend the money and sacrifice some internal space. Frame the inside of the walls and put in insulation.
  - radicalbyte 7y ago
    That's if you're even allowed to do that. Listed buildings are a pain.
myspy 7y ago
German houses build of wood are hundreds of years old, so that shouldn't be a problem.

bjelkeman-again 7y ago

There is a lot of good information here: https://www.swedishwood.com/about_wood/about-glulam/ https://www.swedishwood.com/about_wood/about-glulam/

benj111 7y ago

Centuries? Reinforced concrete is 150 years old, steel frame construction a little less so.

barrkel 7y ago
Sure, but we have concrete buildings still standing from Roman times - most famously, the Pantheon. I grew up in a cottage a couple of hundred years old, with thick walls built from stone and mortar. It's not unusual to live in a house that's over a century old in Europe. I've also lived in a wooden house - more of a three room + toilet chalet, really. Biggest irritations were all the noises from thermal expansion in the summer, and the fact rats could eat their way in. I think it's a bit more effort to actively maintain wood and be sure it's in good condition than brick and concrete construction. That cottage, btw - the roof had a wood frame, but it wasn't the original - that had burned down along with the thatch at least once, and been replaced some time before we moved in.
- benj111 7y ago
  If concrete is similar enough to reinforced concrete. Isn't engineered wood similar enough to normal wood?
  - pjc50 7y ago
    Reinforced concrete has different failure modes. The UK built a lot of precast concrete "panel" houses after the war, some of which are disintegrating badly: https://www.peterbarry.co.uk/blog/houses-of-non-traditional-construction-common-property-defects-6/ https://www.peterbarry.co.uk/blog/houses-of-non-traditional-... Another e.g. concrete disintegrating due to use of mine waste: https://www.theguardian.com/money/2009/nov/29/mundic-test-crumbling-concrete-mortgages https://www.theguardian.com/money/2009/nov/29/mundic-test-cr...
    - benj111 7y ago
      Different failure modes, different tensile strength, not really the same at all. That was kind of my point :)
- willyt 7y ago
  Roman concrete doesn’t have the same chemistry as modern concrete.
  - jabl 7y ago
    And, Roman concrete doesn't have steel rebar which rusts and cracks the concrete.
    - dsfyu404ed 7y ago
      Eh, properly done reinforced concrete should last hundreds of years. Of course it's possible to use the wrong concrete formula for the job (the concrete for your driveway is not the same as the concrete for a boat ramp) but if done right it should last.
  - marmaduke 7y ago
    What’s different? I’m aware of the modern mix with cement sand stone, but I’m guessing romans didn’t have the cement?
    - jbay808 7y ago
      As far as I know, the romans had better cement. We're still trying to reverse engineer it.
      - lsc 7y ago
        this is my understanding as well... but I wonder how much of that is that they just had more variable cement, and the stuff that wasn't incredibly great turned to dust long ago? Certainly, our modern processes are more repeatable and produce a narrower range of results. What if the existent buildings are outliers of the roman process?
        jbay808 7y ago
        Attributing the accomplishments of the past to survivor bias is a popular line of thought these days, but... It's unlikely. They used a completely different chemical formula than we do. If you have two processes X and Y, and you observe consistently that Y >> X, and you know that Y and X are produced by different processes so you don't have a strong prior on the mean of Y being similar to the mean of X, then you should conclude it's very likely that the mean of Y is greater than the mean of X. Even if you know for certain that you only have the best samples of Y. But more importantly, we don't really care if the romans also built a bunch of bad buildings using counterfeit cement with a botched formula, that failed to last until today. What matters is that we don't have the technology today that can match their best work. That's what makes it worthy of study.
anonuser123456 7y ago
>Reinforced concrete is 150 years old Do you mean steal reinforced concrete lasts 150 years or that the technology is 150 years old? My understanding is that reinforced concrete has a service life of 50 years and 80 years if protected with a sacrificial anode of some sort.
- benj111 7y ago
  That the technology is 150 years old. https://en.m.wikipedia.org/wiki/Reinforced_concrete https://en.m.wikipedia.org/wiki/Reinforced_concrete

chadcmulligan 7y ago

I had a home in the 90's that had laminated structural beams, I don't live there any more, but last time I drove past it was still standing. I think its pretty common for housing in Australia, here's some info https://www.thefifthestate.com.au/innovation/materials/explainer-everything-you-need-to-know-about-mass-timber/ https://www.thefifthestate.com.au/innovation/materials/expla... Laminated plywood has been used for a long time (70's?), and has been used as cross bracing on timber framed houses. There's also all the sorts of chipboard which although aren't structural are glued. So I suppose there's a fairly long history there with glued timbers. Its the usage as multi storey buildings that is new I guess. Edit: apparently plywood was first made in 1797 https://en.wikipedia.org/wiki/Plywood https://en.wikipedia.org/wiki/Plywood, wow

jabl 7y ago
The WWII Mosquito was made from plywood. Some of them sent to the tropics had problems with the moisture weakening the glue. But AFAIK those used different glue than what is used today in plywood production, not to mention 1797.

radicalbyte 7y ago

Timber at least can last a very long time. There are houses in the UK which dates from the time of Shakespeare which are still standing. I'm not sure what's worse: a cheap wooden structure which lasts 50-100 years or a strong brick structure which lasts hundreds. Here in Europe we have a large stock of houses from the 1950's which cost 300 EUR a month to heat and cannot be insulated. For a modern passive house costs are closer to 30 EUR a month.

Harvey-Specter 7y ago
Any building can be insulated, you just have to spend the money and sacrifice some internal space. Frame the inside of the walls and put in insulation.
- radicalbyte 7y ago
  That's if you're even allowed to do that. Listed buildings are a pain.

myspy 7y ago

German houses build of wood are hundreds of years old, so that shouldn't be a problem.