How to design a house to last 1000 years • Hacker News Board

Re: How to design a house to last 1000 years

#381

Post by lmm » Thu, Jan 06, 2022, 8:03 AM UTC

flanbiscuit wrote: post #142

tablespoon wrote: post #116

Earlier quoted context omitted.

> Agreed. The idea that homes don't last 1000 years because of their construction quality is conflating correlation and causation. Homes don't last that long because ideas about what (or where) a home should be don't last 1000 years. Heck, in recent times, they hardly last 100 years. And (IIRC) in Japan they often don't last past one owner, since a new owner will typically want to build a new house for themselves on…

> in Japan they often don't last past one owner This has been brought up before on HN and I remember a comment mentioning that they thought it was due to the fact that earthquake proofing technology advances quickly in Japan so an old house might not be up to the most current standard. Curious if that's correct, and if not, why is this so common in Japan then.

I think earthquakes, volcanoes and the like may have been the original reason that the culture sees buildings as transitory things. But like many cultural things it's now self-sustaining.

Re: How to design a house to last 1000 years

#382

Post by pmontra » Thu, Jan 06, 2022, 8:05 AM UTC

jandrese wrote: post #155

tibbydudeza wrote: post #106

Earlier quoted context omitted.

Have they ever figured out how the Romans made concrete and got away with not using rebar ???.

My making the walls incredibly thick, not having large overhangs, and having the foresight to build an empire in a seismically dead area.

Rome is a moderately seismic area suffering from amplification of seismic waves from earthquakes in the more seismic areas in the mountains. Basically all of Italy is seismic. Part of the Colosseum was destroyed by an earthquake in 1349. The google translation of this Italian page is quite good at explaining what happened https://www.focus.it/cultura/storia/perche-il-colosseo-e-cro...

TLDR, the asymmetrical 4-2 storeys shape is the result of that earthquake when the top of the part of the building built on softer ground felt down.

Re: How to design a house to last 1000 years

#383

Post by benwills » Thu, Jan 06, 2022, 8:33 AM UTC

nashashmi wrote: post #215

Animats wrote: post #117

Earlier quoted context omitted.

"rigid steel structure" Steel is springy. Tall steel-framed buildings and bridges routinely sway in wind, which is usually harmless to the structure but annoying to occupants. Unless you get harmonic oscillation, where the energy stored in the motion builds up, which can be a problem and has destroyed bridges. Much of seismic design involves connections which raise the resonant frequency of the structure so it can't…

Rigidity is actually a variable. rigid in the simplest of definition does mean no springy action. Rigid through various fixed connectors implies some spring like behaviors. This is my favorite topic and I could go on and on about this. Point: it is a matter of precise definition. How rigid are we talking?

I'm fascinated by structural engineering as a sort of hobbyist (who has done some basic home construction/renovation and plans to build a house/houses one day) and would definitely not be opposed if you went on and on about it.

Re: How to design a house to last 1000 years

#384

Post by MrsPeaches » Thu, Jan 06, 2022, 9:04 AM UTC

dr_dshiv wrote: post #343

archontes wrote: post #303

Earlier quoted context omitted.

Literally everything. Harmonic oscillators all the way down.

I'm Hooked. Tell me more.

There’s a mass of theory out there. For some, that puts a spring in their step but others shouldn’t let their spirits be dampened.

Re: How to design a house to last 1000 years

#385

Post by littlestymaar » Thu, Jan 06, 2022, 9:40 AM UTC

theluketaylor wrote: post #373

littlestymaar wrote: post #330

Earlier quoted context omitted.

> here with new thing ones you want to heat up the air so you don't want radiator to be warm but air in well insulated building. This is more complicated than this, and the construction industry has actually gone back and forth on this topic for the past 40 years. A few consideration against your point: - When you heat air, you dry it up, which can be pretty uncomfortable for the inhabitants. - Air stratification is…

> There exists sophisticated systems with heat exchangers to collect heat from the outgoing air and warm the incoming air, but those are really expensive and far from ubiquitous. Energy recovery ventilation units are not that expensive and are required by code for new construction here in Ontario as of 2017. Adds some cost to the HVAC of a new build, but not that much.

> Energy recovery ventilation units are not that expensive […] Adds some cost to the HVAC of a new build, but not that much.

I've recently had my (individual) house built, and it was 3-4 times more expensive than a regular system. It's not a prominent part of the entire budget for a house, but the difference still made me chose the regular one. But maybe a significant part of the price difference was just a premium for having the high-end tech, more than a real cost difference for the builder.

> are required by code for new construction here in Ontario as of 2017

Interesting. Even for individual houses? Maybe that's a good idea to make it mandatory, if the premium hypothesis above turned to be true.

Re: How to design a house to last 1000 years

#386

Post by Pephers » Thu, Jan 06, 2022, 10:36 AM UTC

Slate roofs are a solid choice. Our 1875 house in Denmark still has the original roof with Port Madoc slates. It's in good condition, and the few slates that have broken can easily be replaced.

Slate has a higher upfront cost than other roofing materials, but it's a shame that so many houses are built with concrete roof tiles or fibercement roofing which only last 25-35 years before needing a complete replacement. In comparison, the typical life span for roofs with clay tiles are 75+ years and slate roofs 100+ years.

Re: How to design a house to last 1000 years

#387

Post by ethbr0 » Thu, Jan 06, 2022, 10:57 AM UTC

rsync wrote: post #260

clairity wrote: post #251

Earlier quoted context omitted.

gotcha, my bad for misconstruing your point. joint strength relative to span strength is definitely a non-obvious issue to the average home owner-builder. i also vastly prefer wood/mass timber for aesthetic reasons. mass timber has better burn characteristics than steel, and i'd recently read that builders are actually starting to surround steel columns with cross-laminated timber (rather than concrete) for that reas…

"... and i'd recently read that builders are actually starting to surround steel columns with cross-laminated timber ..." Somewhat relevant - might interest you: https://easternwhitepine.org/this-office-buildings-wooden-fr... TAMedia office building in Zurich.

> ...mass timber...

Not sure if this is a regional / language difference, but I've more commonly seen it called "engineered wood" [0]. Which apparently now also includes transparent(?!) wood composite [1].

[0] https://en.wikipedia.org/wiki/Engineered_wood

[1] https://en.wikipedia.org/wiki/Transparent_wood_composite

Re: How to design a house to last 1000 years

#388

Post by maxwell86 » Thu, Jan 06, 2022, 12:34 PM UTC

hwillis wrote: post #317

maxwell86 wrote: post #306

Earlier quoted context omitted.

Sure, but what's the alternative? Dig out all other buildings that failed over the last 1000 years, figure out how they failed and why, and take action? You can just copy what is known to work instead.

Or like, look at any of the million dilapidated houses and realize that 1. most houses leak at some point and 2. termites eat wood. Then conclude that actually, maybe .0001% of wood houses lasting for 1000 years is not actually good evidence that wood is a material that easily lasts 1000 years. Then think twice about using wood. Personally I'd a concrete dome: https://en.wikipedia.org/wiki/Pantheon,_Rome

The claim here is that one would look at _ALL_ 1000+ year ld buildings, and then decide what to build.

You are building the strawman of looking at _ONE_ 1000+ year old building, and then building that because it must work. Nobody is arguing about this, and probably everybody here would agree that doing this is a bad idea.

---

With that out of the way, there aren't many 1000+ year old buildings made out of wood. There are some, e.g., japanese temples, that IIRC have burned a couple of times along the way, but are 1000+ year old and build out of wood.

But most buildings in the 1000+ year old range are made out of stone and only partially out of wood (cathedrals, etc.).

Re: How to design a house to last 1000 years

#389

Post by theluketaylor » Thu, Jan 06, 2022, 2:20 PM UTC

littlestymaar wrote: post #385

theluketaylor wrote: post #373

Earlier quoted context omitted.

> There exists sophisticated systems with heat exchangers to collect heat from the outgoing air and warm the incoming air, but those are really expensive and far from ubiquitous. Energy recovery ventilation units are not that expensive and are required by code for new construction here in Ontario as of 2017. Adds some cost to the HVAC of a new build, but not that much.

> Energy recovery ventilation units are not that expensive […] Adds some cost to the HVAC of a new build, but not that much. I've recently had my (individual) house built, and it was 3-4 times more expensive than a regular system. It's not a prominent part of the entire budget for a house, but the difference still made me chose the regular one. But maybe a significant part of the price difference was just a premium f…

I believe the requirement that came in earlier for large apartments and condos, but 2017 was the date for detached homes (sadly by far the most common form of development here)

I’m not a super expert, but I believe HVAC here in new builds is about 20-30k, split fairly evenly between parts and install. ERVs are around 1-2k for parts and another grand or so for installation (and significantly easier when done at build time). It likely helps we have such extreme climate our HVAC costs are already quite high, so an extra $1000 here or there isn’t a big deal.

Places more moderate it could easily be a much bigger percentage of the budget and come with reduced ROI. Right now over night I’m heating about 30C temperature difference and I live in one of the most mild parts of the country. Recovering energy is a big deal, as is capturing moisture to reduce load on the humidifier (evaporating water is far from free).

Re: How to design a house to last 1000 years

#390

Post by littlestymaar » Thu, Jan 06, 2022, 4:03 PM UTC

theluketaylor wrote: post #389

littlestymaar wrote: post #385

Earlier quoted context omitted.

> Energy recovery ventilation units are not that expensive […] Adds some cost to the HVAC of a new build, but not that much. I've recently had my (individual) house built, and it was 3-4 times more expensive than a regular system. It's not a prominent part of the entire budget for a house, but the difference still made me chose the regular one. But maybe a significant part of the price difference was just a premium f…

I believe the requirement that came in earlier for large apartments and condos, but 2017 was the date for detached homes (sadly by far the most common form of development here) I’m not a super expert, but I believe HVAC here in new builds is about 20-30k, split fairly evenly between parts and install. ERVs are around 1-2k for parts and another grand or so for installation (and significantly easier when done at build…

Thanks for your answer. That's a great reminder that everything building-related depends a lot on the weather of the region things are being built!