6 ms·

One good thing the US and Canada does is to not use cement for houses ! It is somewhat negated by the terrible insulation in most homes in the US (and the fact

One good thing the US and Canada does is to not use cement for houses ! It is somewhat negated by the terrible insulation in most homes in the US (and the fact that homes tend to last less long I guess). Does anyone have any data on how much gets emitted for house construction depending on the material ?

kibwen 7y ago
Planting trees in order to specifically harvest them for construction would actually count as a form of carbon sequestration, and although I doubt that even comes close to offsetting the carbon emitted by the rest of the construction process it might still make wood-frame construction one of the most relatively green ways to build a house. Log cabins actually have fantastic insulation properties, since the wood has enough thermal mass that it partially warms the house during the night and cools it during the day. Of course most wood-frame houses are nowhere close to using as much wood as an actual log cabin, but modern insulation techniques (especially regarding windows) are far from "terrible"; when I think bad insulation in the US, I think of the houses that were built in the 40s and 50s.
tyfon 7y ago
I'm not sure about the amount of gas, however it is quite common to make the ground floor of concrete here in Norway. However it's not solid, it has a core of Styrofoam to insulate so it. The rest of the houses are usually of wood/glass that is heavily insulated. It would be interesting to see if you could make the foundations out of wood or something like that instead. All new buildings has to adhere to very strict codes of how to be constructed [1]. We also have the worlds tallest wooden building [2] here so maybe this is the future instead of concrete/steel skyscrapers. [1] https://dibk.no/byggereglene/byggteknisk-forskrift-tek17/ https://dibk.no/byggereglene/byggteknisk-forskrift-tek17/ [2] https://www.dezeen.com/2019/03/19/mjostarne-worlds-tallest-timber-tower-voll-arkitekter-norway/ https://www.dezeen.com/2019/03/19/mjostarne-worlds-tallest-t...
- cheerlessbog 7y ago
  I hope that wooden building has excellent (and redundant) sprinklers. It didn't mention fireproof treatment of some kind. Grenfell showed how fast a tower can burn if it's flammable.
  - SECProto 7y ago
    Structural properties are interesting. Fires are a combination of fuel, oxidizer, and initiator. Can't really avoid the last one, accidents happen, but you can slow it down. Grenfell was interesting. My understanding (inquiry is still ongoing, so conditional): because the panels are so thin, they have much larger oxidizer availability to the fuel - like burning a piece of paper held vertically, the rising flames will spread and consume available fuel quickly. Mass timber, on the other hand, is fairly resistant to fire [1] - initiates slowly, takes a long time to burn through - it's what makes logs in a wood stove burn over hours, not seconds. And while the outside is slowly charring, the core maintains structural strength - quite unlike structural steel as it heats (the steel connectors in this building are actually one of the weak points! [1]). Sprinklers in any high rise is necessary to ensure it has an adequate fire rating (eg, it will remain structurally stable/safe for 2 hours is I think the standard in my country?). It's not like taking a stick built house and making it taller. Caveat: I have studied structures/fire rating stuff, but am not a professional. [1] for your further reading pleasure: https://www.moelven.com/news/news-archive2/2018/how-the-worlds-tallest-timber-building-withstands-fire/ https://www.moelven.com/news/news-archive2/2018/how-the-worl...
galangalalgol 7y ago
The us doesn't use concrete for residential walls (very often) but that is actually quite good from an insulation perspective. Hollow wood framed walls have a lot better r factor than solid concrete. We do have solid concrete foundations. Edit: hollow walls filled with fiberglass to keep the air still
- taneq 7y ago
  With hollow walls you can just use blow-in wool or cellulose insulation to make it even better. Can't really improve concrete without gluing polystyrene to it. Hmm, could you just mix expanded polystyrene balls in to cement to make a high-R composite that's still strong enough to be structural?
  - the8472 7y ago
    Foam glass bricks are available as insulation layers as alternative to polystyrene. There was a german company that produced foam glass concrete but they shuttered production.
  - shereadsthenews 7y ago
    Usually concrete walls have a foam core. Solid concrete is only about R0.5/in, about half as good as wood. Even so, insulated cavities are totally obsolete. Exterior foam is far superior.
    - taneq 7y ago
      Wow, really? Interesting, the one's I'm familiar with (used in tilt-up construction) are just solid concrete (maybe plus some rebar). Totally with you on exterior foam though, you want the insulation outside of the thermal mass if at all possible.
      - dillonmckay 7y ago
        Check out ICF: https://en.m.wikipedia.org/wiki/Insulating_concrete_form https://en.m.wikipedia.org/wiki/Insulating_concrete_form There may be some copyright shenanigans w/ that page. There have also been successfully constructed in-ground pools using this material, but appears to be controversial to traditional pool-builders.
golemiprague 7y ago
It is not applicable to many places in the world where there is no such an abandon of land space and wood supply. The American suburbia has its own environmental impact which might offset any benefit comparing to more congested tall buildings areas.

kibwen 7y ago

Planting trees in order to specifically harvest them for construction would actually count as a form of carbon sequestration, and although I doubt that even comes close to offsetting the carbon emitted by the rest of the construction process it might still make wood-frame construction one of the most relatively green ways to build a house. Log cabins actually have fantastic insulation properties, since the wood has enough thermal mass that it partially warms the house during the night and cools it during the day. Of course most wood-frame houses are nowhere close to using as much wood as an actual log cabin, but modern insulation techniques (especially regarding windows) are far from "terrible"; when I think bad insulation in the US, I think of the houses that were built in the 40s and 50s.

tyfon 7y ago

I'm not sure about the amount of gas, however it is quite common to make the ground floor of concrete here in Norway. However it's not solid, it has a core of Styrofoam to insulate so it. The rest of the houses are usually of wood/glass that is heavily insulated. It would be interesting to see if you could make the foundations out of wood or something like that instead. All new buildings has to adhere to very strict codes of how to be constructed [1]. We also have the worlds tallest wooden building [2] here so maybe this is the future instead of concrete/steel skyscrapers. [1] https://dibk.no/byggereglene/byggteknisk-forskrift-tek17/ https://dibk.no/byggereglene/byggteknisk-forskrift-tek17/ [2] https://www.dezeen.com/2019/03/19/mjostarne-worlds-tallest-timber-tower-voll-arkitekter-norway/ https://www.dezeen.com/2019/03/19/mjostarne-worlds-tallest-t...

cheerlessbog 7y ago
I hope that wooden building has excellent (and redundant) sprinklers. It didn't mention fireproof treatment of some kind. Grenfell showed how fast a tower can burn if it's flammable.
- SECProto 7y ago
  Structural properties are interesting. Fires are a combination of fuel, oxidizer, and initiator. Can't really avoid the last one, accidents happen, but you can slow it down. Grenfell was interesting. My understanding (inquiry is still ongoing, so conditional): because the panels are so thin, they have much larger oxidizer availability to the fuel - like burning a piece of paper held vertically, the rising flames will spread and consume available fuel quickly. Mass timber, on the other hand, is fairly resistant to fire [1] - initiates slowly, takes a long time to burn through - it's what makes logs in a wood stove burn over hours, not seconds. And while the outside is slowly charring, the core maintains structural strength - quite unlike structural steel as it heats (the steel connectors in this building are actually one of the weak points! [1]). Sprinklers in any high rise is necessary to ensure it has an adequate fire rating (eg, it will remain structurally stable/safe for 2 hours is I think the standard in my country?). It's not like taking a stick built house and making it taller. Caveat: I have studied structures/fire rating stuff, but am not a professional. [1] for your further reading pleasure: https://www.moelven.com/news/news-archive2/2018/how-the-worlds-tallest-timber-building-withstands-fire/ https://www.moelven.com/news/news-archive2/2018/how-the-worl...

galangalalgol 7y ago

The us doesn't use concrete for residential walls (very often) but that is actually quite good from an insulation perspective. Hollow wood framed walls have a lot better r factor than solid concrete. We do have solid concrete foundations. Edit: hollow walls filled with fiberglass to keep the air still

taneq 7y ago
With hollow walls you can just use blow-in wool or cellulose insulation to make it even better. Can't really improve concrete without gluing polystyrene to it. Hmm, could you just mix expanded polystyrene balls in to cement to make a high-R composite that's still strong enough to be structural?
- the8472 7y ago
  Foam glass bricks are available as insulation layers as alternative to polystyrene. There was a german company that produced foam glass concrete but they shuttered production.
- shereadsthenews 7y ago
  Usually concrete walls have a foam core. Solid concrete is only about R0.5/in, about half as good as wood. Even so, insulated cavities are totally obsolete. Exterior foam is far superior.
  - taneq 7y ago
    Wow, really? Interesting, the one's I'm familiar with (used in tilt-up construction) are just solid concrete (maybe plus some rebar). Totally with you on exterior foam though, you want the insulation outside of the thermal mass if at all possible.
    - dillonmckay 7y ago
      Check out ICF: https://en.m.wikipedia.org/wiki/Insulating_concrete_form https://en.m.wikipedia.org/wiki/Insulating_concrete_form There may be some copyright shenanigans w/ that page. There have also been successfully constructed in-ground pools using this material, but appears to be controversial to traditional pool-builders.

golemiprague 7y ago

It is not applicable to many places in the world where there is no such an abandon of land space and wood supply. The American suburbia has its own environmental impact which might offset any benefit comparing to more congested tall buildings areas.