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Underground construction is really hard to do correctly. Partial earth bermed foundations as you mentioned are a good compromise, especially if the earth is bui

by kortex 4y ago

Underground construction is really hard to do correctly. Partial earth bermed foundations as you mentioned are a good compromise, especially if the earth is built up. But even then, drainage and soil pressure are big engineering concerns. Also you have no control over how much thermal interface you have. My office is on the first floor on a slab. It's great in the summer and freezing in the winter, despite a carpet. Digging down becomes increasingly expensive vs equivalent volume building up. Why not just use ground source heat pumps? It's much easier to bury some tubes than habitable spaces. It's easier to move heat/cold where you need it. You aren't forced into a fixed thermal flux.

LinuxBender 4y ago
Underground construction is really hard to do correctly. I agree it is harder to do correctly and costs more. It's an investment that if done right could outlast any above ground home. But that is quite a loaded caveat on my part, done right. That's why I envision this being done in a factory and very specific instructions and compliance requirements that if adhered to should produce more predictable results. The bunkers I see people building today are all custom one-off designs and I think that is where they get into trouble. I do like the idea of heat pumps. That would be a balanced trade-off for those that do not want to mess with putting in a home under ground.
- shrimp_emoji 4y ago
  >It's an investment that if done right could outlast any above ground home. I would think this was true, but what I've learned so far suggests it's not... Underground, you're not finding refuge from harmful forces on your structure; they exists there too. Things shift, things crack, things leak, humidity causes problems, the whole exterior now endures a chemical interface with the surroundings (and all your Vault-Tec steel will corrode at some speed determined by the nature of the local media). If you're lucky enough to have near-surface bedrock where you are, digging into that is probably your best bet, but, even then, it seems like an uphill battle.
blip54321 4y ago
I'm really not sold on the costs of digging down being all that high, long-term. I'm 100% sold on it being expensive today, but I can come up with ways to drive them /way/ down with automation. The critical thing is: 1) You don't need materials. 2) You don't need to transport anything other than a digger I agree it's hard, like engineering a CPU was hard, but I think Elon's got the right idea with the Boring Company. It's not /fundamentally/ expensive. Fundamentally, building in-place with available materials should, some day, be cheap.
- eropple 4y ago
  > 1) You don't need materials. In this context, you do. You need material structural stability (which is nontrivial, even for partially bermed structures; digging down further is a different story too) and for human habitation. Even above-ground you see retaining walls everywhere in places like New England because dirt likes to move. Worse, you'll need relatively expensive materials, and ones that are OK with contact with a lot of moisture. Maybe plastics can be the answer to some degree, if ones that are structurally sound and not tasty to microorganisms can be employed en masse, but the default answer is probably steel, and that won't last forever (or even all that long). Beyond that? People aren't generally high on dirt walls and floors. And smoothing stone to presentation levels in-place, ensuring regularity, etc. is not a trivial task. It could be done, don't get me wrong. But we have wear and decay problems above the surface that probably pale in comparison.
  - blip54321 4y ago
    I feel like the materials are whatever is found on site. That may mean that a machine may need to be able to sort, smelt, sinter, form, ram, engrave, or otherwise process whatever it found on-site. That's definitely non-trivial, but in the sense of making a CPU with millions of transistors, and not in the sense of Mt. Rushmore. The R&D costs will be astronomical, but there isn't much there which is /fundamentally/ expensive, at least so long as you're not going to deep. I can describe a number of beachheads and early markets -- places where you don't need all of that at one, or ultralow costs. I think the Boring Company has a decent one.
oliveshell 4y ago
And that’s without even mentioning light. Sure, sunlight can be piped down underground for natural lighting, but I’d really miss being able to see trees and blue sky from my office desk.

by kortex 4y ago

LinuxBender 4y ago

Underground construction is really hard to do correctly. I agree it is harder to do correctly and costs more. It's an investment that if done right could outlast any above ground home. But that is quite a loaded caveat on my part, done right. That's why I envision this being done in a factory and very specific instructions and compliance requirements that if adhered to should produce more predictable results. The bunkers I see people building today are all custom one-off designs and I think that is where they get into trouble. I do like the idea of heat pumps. That would be a balanced trade-off for those that do not want to mess with putting in a home under ground.

shrimp_emoji 4y ago
>It's an investment that if done right could outlast any above ground home. I would think this was true, but what I've learned so far suggests it's not... Underground, you're not finding refuge from harmful forces on your structure; they exists there too. Things shift, things crack, things leak, humidity causes problems, the whole exterior now endures a chemical interface with the surroundings (and all your Vault-Tec steel will corrode at some speed determined by the nature of the local media). If you're lucky enough to have near-surface bedrock where you are, digging into that is probably your best bet, but, even then, it seems like an uphill battle.

blip54321 4y ago

I'm really not sold on the costs of digging down being all that high, long-term. I'm 100% sold on it being expensive today, but I can come up with ways to drive them /way/ down with automation. The critical thing is: 1) You don't need materials. 2) You don't need to transport anything other than a digger I agree it's hard, like engineering a CPU was hard, but I think Elon's got the right idea with the Boring Company. It's not /fundamentally/ expensive. Fundamentally, building in-place with available materials should, some day, be cheap.

eropple 4y ago
> 1) You don't need materials. In this context, you do. You need material structural stability (which is nontrivial, even for partially bermed structures; digging down further is a different story too) and for human habitation. Even above-ground you see retaining walls everywhere in places like New England because dirt likes to move. Worse, you'll need relatively expensive materials, and ones that are OK with contact with a lot of moisture. Maybe plastics can be the answer to some degree, if ones that are structurally sound and not tasty to microorganisms can be employed en masse, but the default answer is probably steel, and that won't last forever (or even all that long). Beyond that? People aren't generally high on dirt walls and floors. And smoothing stone to presentation levels in-place, ensuring regularity, etc. is not a trivial task. It could be done, don't get me wrong. But we have wear and decay problems above the surface that probably pale in comparison.
- blip54321 4y ago
  I feel like the materials are whatever is found on site. That may mean that a machine may need to be able to sort, smelt, sinter, form, ram, engrave, or otherwise process whatever it found on-site. That's definitely non-trivial, but in the sense of making a CPU with millions of transistors, and not in the sense of Mt. Rushmore. The R&D costs will be astronomical, but there isn't much there which is /fundamentally/ expensive, at least so long as you're not going to deep. I can describe a number of beachheads and early markets -- places where you don't need all of that at one, or ultralow costs. I think the Boring Company has a decent one.

oliveshell 4y ago

And that’s without even mentioning light. Sure, sunlight can be piped down underground for natural lighting, but I’d really miss being able to see trees and blue sky from my office desk.