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How to design a house to last 1000 years

constructionphysics.substack.com

351–360 of 402 posts

Re: How to design a house to last 1000 years

#353
I'm sceptical about the slate roof too. Houses with slate roofs routinely lose slates in high winds which is dangerous. I narrowly missed being decapitated waking around Brighton in a big storm in '90. I assume that this is a maintenance issue, the fixtures use to hold the slate tend to have a shorter lifespan than the slate itself. Many buildings in the UK that were originally slate roofed been converted to conventional ceramic or concrete tile.

I'm surprised that there wasn't any discussion about thatch for the roof. It has a multi-thousand year history in the UK. So while it goes in and out of fashion, there's always someone around who knows how to do it.

I had friends who lived in 500 year old cottage with an oak frame and a thatched roof. It has several very long maintenance cycles, annual, decennial, and semicentennial, but even those can be occasionally missed. It's a flexible form of construction in more ways than one

Re: How to design a house to last 1000 years

#356
post #325

As someone who is living in a generational home this article brings several questions to mind. (But it’s a fun thought experiment) 1) presumably this home isn’t going to be built by someone in their 20s and will likely be built by someone who has accumulated some wealth. That puts them at 30-60 years old. Is the 1000 year benchmark because you want to pass the home down to your kids? 2) if so, do you think they will…

The proposed building in the article is essentially a open rectangle, with no interior load-bearing walls. Floor joists are wood (across the steel beams), and partition walls are also wood. Seems like it'd be easy to renovate.

Re: How to design a house to last 1000 years

#357
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…

> Tension joints for wood are seen in classic Japanese construction

If you’re referring to the wood bracket system, that is true, but for posterity, it didn’t originate in Japan. Imported, very likely via Korea (which also uses it in their classic construction), from China.

Re: How to design a house to last 1000 years

#358

Earlier quoted context omitted.

Steel beams buried in the ground, no matter what they're made of, are going to rot away quite rapidly if they contact any other metal, due to galvanic corrosion. I think you'd be better off with basalt fiber reinforced concrete for anything going in the ground. It's going to be strong, and it won't rot.

There is also basalt rebar. Last I checked, some building codes allow equivalent 1:1 tradeoff with classic rebar - even though the basalt rebar is stronger. From what I understand, basalt rebar does not have the usual problem of regular rebar where oxidizing (rust) expansion can cause cracking in concrete. Additionally, the temperature expansion rates are much closer (rebar vs concrete). My main hesitation would be t…

> Last I checked, some building codes allow equivalent 1:1 tradeoff with classic rebar - even though the basalt rebar is stronger.

Basalt rebar has a much lower elastic modulus, so when it fails, it fails. Steel on the other hand has a much larger elastic region - where the steel stretches while still carrying the same load. Part of the benefit of reinforced concrete is elastic failure - essentially every (properly) designed reinforced concrete structure is designed to fail with the tensile side of concrete cracking while the steel rebar still caries load, giving visual evidence that the concrete has failed. This is called elastic failure. This works because steel has a large ductile range. Basalt rebar doesn't fail the same way, so substituting it 1:1 seems inappropriate, regardless of it being stronger (per unit area).

I did find one random study[1] that substituted basalt rebar 1:1 with steel and compared the failure modes, and found that basalt-reinforced had cracking load essentially the same as a steel-reinforced, but a much larger ultimate load. Interestingly, the higher ultimate strength more than makes up for the much lower elastic modulus.

[1] https://www.icontrolpollution.com/articles/investigation-of-...

Re: How to design a house to last 1000 years

#359
post #232

Earlier quoted context omitted.

> If I had an unlimited budget and was aiming for >1000 years I would pour the piles to bedrock with stainless rebar inside fly-ash concrete and top those pilings with plate connectors into which you could socket large wooden columns (perhaps 8x8) and build the structure with large wooden members connected with steel connectors and column caps, etc. Are there any existing buildings constructed that way that have stoo…

York Minster in England is mostly 1000 years old. There are some nice stories about how it handled a serious fire in 1984 here, (starting about 18 minutes in) https://www.bbc.co.uk/sounds/play/m0007pws . eg, the 2000 year old Roman drainage system got used for the first time in 1000 years because lots of water got inside the building from the fire hoses. When rebuilding it, they had to decide whether to remake it in…

There is a story about one of the Ivy League universities. IIRC, in one of the century-or-two old buildings, there was a need to replace some main interior beams in a roof. Among the staff, someone knew someone who remembered something about this. Turns out, there was a special grove of trees, still under control of the university, which had been planted to provide replacement beams -- after 150 years of growth.

An old story about people having thought for the long term.

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