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

Re: How to design a house to last 1000 years

#391

Post by lenkite » Thu, Jan 06, 2022, 8:02 PM UTC

ThrustVectoring wrote: post #230

lenkite wrote: post #199

Earlier quoted context omitted.

Wish we could re-discover how to produce Roman Concrete, which has already proven its long-lasting efficacy. https://en.wikipedia.org/wiki/Roman_concrete .

My understanding is that modern concrete would last as long as Roman concrete would, if we built the same types of designs that Romans used concrete for. The big difference is that we want to span gaps without using large unwieldy arches, so we need tensile strength, so we need to use steel reinforcing bar in our concrete, which is the eventual pathway to failure. (Well, that and heavy machinery like semi-tractor tra…

> so it lasted about as long as you'd expect a random rock subject to only compressive loads in a field to last.

Roman Concrete is a bit more special than some 'random rock' thanks to the presence of "aluminous tobermorite" which makes the concrete much stronger and more chemically stable

https://interestingengineering.com/scientists-discover-why-r...

Re: How to design a house to last 1000 years

#392

Post by LorenPechtel » Thu, Jan 06, 2022, 8:37 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

Concrete with basalt rebar. It doesn't rust like steel.

Re: How to design a house to last 1000 years

#393

Post by PTOB » Thu, Jan 06, 2022, 8:40 PM UTC

wing-_-nuts wrote: post #44

Gravityloss wrote: post #17

Why have the chimney outside? It's very inefficient... https://www.quora.com/Why-do-American-houses-often-have-the-...

Why was that done traditionally? Because if you had a chimney fire, you could hook your mules to it, pull it down, and save the house.

c.f. "Little House on the Prairie". Chimney fire is for real.

Re: How to design a house to last 1000 years

#394

Post by amai » Thu, Jan 06, 2022, 9:09 PM UTC

Given the danger of a nuclear war, you might want to design your house like the https://en.wikipedia.org/wiki/Cheyenne_Mountain_Complex

"The complex was built under 2,000 feet (610 m) of granite on 2 hectares (5 acres). Fifteen three-story buildings are protected from movement, e.g. earthquake or explosion, by a system of giant springs that the buildings sit on and flexible pipe connectors to limit the operational effect of movement....

The bunker is built to deflect a 30 megaton nuclear explosion as close as 2 kilometers. Within a mountain tunnel are sets of 25-ton blast doors and another for the civil engineering department...The complex has its own power plant, heating and cooling system, and water supply"

Re: How to design a house to last 1000 years

#395

Post by clairity » Thu, Jan 06, 2022, 9:52 PM UTC

ethbr0 wrote: post #387

rsync wrote: post #260

Earlier quoted context omitted.

"... 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

my impression is that 'engineered wood' is a slightly different aggregation than 'mass timber', with engineered wood including things like plywood, while mass timber is focused on the 'timber' aspect (more structurally focused, usually larger).

Re: How to design a house to last 1000 years

#396

Post by kjs3 » Fri, Jan 07, 2022, 2:32 AM UTC

Animats wrote: post #117

rsync wrote: post #98

This is a very odd design document and it makes me think this author has thought a lot about materials and buildings but not actually built anything . The steel moment frame, to someone with shallow knowledge, sounds so strong and resilient . But in fact, a rigid steel structure is more vulnerable to seismic (and even wind) loads than wooden framing which can flex and move and dampen those loads naturally. The stainl…

"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…

Steel is springy.

Unless it's not. Steel isn't one homogeneous thing. Depending on what trace elements you add, steel can have wildly different values of strength, rigidity & hardness.

Re: How to design a house to last 1000 years

#397

Post by Hex-3-En » Fri, Jan 07, 2022, 11:25 AM UTC

Tbh just look at houses in e.g. Luebeck, Germany or other old european cities. Some houses still in use have their foundation over 700 years ago and even survived 2 WWs. So, there you go -> thats how to build.

Re: How to design a house to last 1000 years

#398

Post by daydream » Fri, Jan 07, 2022, 7:27 PM UTC

rebuilder wrote: post #257

SkeuomorphicBee wrote: post #175

Earlier quoted context omitted.

> We can, however, apply modern technics and materials when they make sense : insulation, windows, waterways... The article raises an important point that could be a problem when trying to mix old and new build techniques. When talking about brick walls it says: > One tricky thing with this type of assembly is that while it has performed well historically, it doesn’t necessarily play nice with more modern, energy eff…

Well yes, but the example house doesn't seem to be all that optimized for energy efficiency. Look at the illustration showing a fireplace located at the end of the house. That's going to waste so much heat compared to a centrally located one. So I'm not sure how much attention was paid to energy efficiency here.

I came here looking for a comment like this. A fireplace partially exposed to the exterior (as is common nowadays) is essentially entirely decorative and can actually be a net negative in terms of heating the space. seeing that made me question the practicality of the authors other design choices that I know little about.

Re: How to design a house to last 1000 years

#399

Post by ozim » Sat, Jan 08, 2022, 11:37 AM UTC

littlestymaar wrote: post #330

ozim wrote: post #293

Earlier quoted context omitted.

My pet peeve is when people claim that heavy old cast iron radiators are "always better" than new flimsy steel ones. Yes those are better for old houses with old insulation or no insulation because then you wanted radiator to keep warm so you can sit close to it and get yourself warm. Where 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.

> 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…

Yes that is what I am describing as well - that it is more complicated. I am not saying that new steel radiators are somehow superior.

Re: How to design a house to last 1000 years

#400

Post by jacquesm » Sat, Jan 08, 2022, 2:02 PM UTC

Animats wrote: post #262

rsync wrote: post #216

Earlier quoted context omitted.

You misunderstood my comment about steel in the ground ... I was trying to convince the OP that they don't need to worry about the corrosion since even in terrible circumstances the steel still lasts quite a while. With regard to your skyscraper experience: I'm not sure this is an apples-to-apples comparison. Skyscrapers are not made of skyscraper-height columns - they are a stack of elements that are connected every…

they are a stack of elements that are connected every X height that has a well known flex per connection. It's also (hopefully) a uniform flex at every connection. The flex is supposed to be in the beams, not the connections. Stress concentration is bad. Here's an intro.[1] Beams are easy to analyze, and tend to meet their specs, while connections are hard to analyze, and are subject to construction mistakes. The Jan…

Same with long low steel buildings, they usually have a lot of room for expansion built into them because the tops are close enough to the foundation that the angle of the uprights would change a lot if not dealt with in such a way. For higher buildings this isn't as much of a problem because the parts closer to the foundation will likely be closer to ambient.

In one particular case (the steel truss roof of a convention center in Amsterdam) there are many such places where slack was built into it, the structure is many 100's of meters wide and if connected rigidly would put undue stress on the uprights and the foundations.