Concrete: The material that's 'too vast to imagine'

Cheaper (where I am). Let’s WiFi signals through easier, so I need fewer access points.

I’ve worked with both, and the main advantage of concrete would be the sound insulation. But I feel like a quality wood + drywall + insulation installation can come close enough for residential purposes.

They sequester carbon rather than produce it.

They're easy to modify and expand.

They're durable and last forever if you take care of them.

Plus the carbon sequestration

And in the case of craftsman style homes the use of wood is very beautiful but of course you could throw a few planks of wood onto a concrete shell.

It’s softer too, I lived in a condo that was all concrete and granite, anytime you bumped into a corner or fell down it just hurt more than wood.

For larger construction, pumped concrete is cheaper to build. It’s generally (but not always) more fireproof without special measures being taken.

You think that concrete is stronger because it looks solid and heavy. In many cases, concrete or other masonry buildings are actually clad buildings with wood or other framing. Also, generally speaking a small scale, poorly built concrete structure will be more solid than a poorly built wooden structure.

I live in an urban house in upstate NY, it’s a wood frame house built in 1925. It’s not a luxury or high-end construction, but there’s no structural reason that it won’t be standing in 2125. Keep a roof on it and control storm water and you’re good to go.

"A six-story building collapsed Friday night in Nairobi, killing at least a dozen people. Several buildings in Kenya have collapsed in the past year. Why?"

https://www.google.com/maps/@42.2662623,-71.8167462,3a,75y,1...

And lots of basements were packed eaeth, a whole nother level of 'unfinished'

I don’t understand if people posting this realise what a low bar this is? Brick and stone houses last a thousand years.

Further, they're designed to exist without modern heating and cooling, and many still don't have those (or they don't work very well). Yet they stand, and often still have perfectly-aligned original wooden trim work, despite being subject to swings in internal temperature and humidity that'd ruin a modern house in a hurry (modern ones are too air-tight to survive that, aren't built with any care to wood grain direction, and use much lower-quality timber throughout, including for trim, though they may benefit from extensive use of dimensionally-stable plywood).

Why they are so old? Did owners not have money to rebuild?

> Rain getting onto the wooden walls? Needs regular repainting?

Most “wooden” US homes do not have wood siding. Vinyl is extremely common, and most homes that predate vinyl have had vinyl installed because it eliminates the maintenance associated with painted wood. Mine is decorative masonry. (And I wish I had vinyl)

They suck if you want to retrofit them to have modern heating and cooling. The high ceilings, giant windows on all sides, large open attics (vital for temp control without AC!), and generally poor sealing (=great if you need them to survive temp and humidity changes throughout the year, and not turn into a giant mold farm like a modern house would) all work against you.

Where I live now, ceiling heights are going back up. 10 years ago it was common to have 9 foot ceilings on the first floor, 8 foot on the second. Now it's common to have 9 foot on the second floor as well. And there are a not-insignificant number of houses being built with 10 foot ceilings.

It's not when you consider that we cut down most of our trees.

Wood will last longer [than reinforced concrete], again, with proper care. But in the end, entropy wins against wood as well. [And again, wood will never outlast the Pyramids].

In civil engineering, there really is no such thing as a free lunch. All materials come with drawbacks.

EDIT: To clarify wording.

Non-reinforced concrete has to be built bigger, but can last a long time. The coliseum is still up - Hoover Dam will also probably last awhile. And that's without much maintenance.

Smaller non-reinforced structures are harder to build. You have to use the concrete to hold itself up which requires a larger structure.

So you're left with reinforcement. There are options for non-rusting rebar, and non-rusting coatings, but I believe they're expensive. Also, any nick or scratch in a coating ruins it. There's also unique and novel research for non-rebar reinforcement - again expensive.

Here in US most buildings are built to last X years. So long as the rebar lasts longer than X, they'll use rebar. Increase X via regulations, and the quality (and cost) of the buildings in that area increases. Otherwise the bidder with the lowest cost of materials is most competitive. Anyone know what it's like in China?

Wood construction, on the other hand, is extremely easy to repair. You can cut away sections and replace them piecemeal, essentially forever.

Wood gives you the ability to continuously build a Ship of Theseus, while structurally compromised concrete structures often require you to tear them down and build them again from scratch.

If you keep the water out, there's no reason why 2x4 and sheetrock shouldn't last a good long time.

I live in New England, and there's plenty of old post-and-beam construction that's held up for a couple of hundred years. Some houses still have their original interior trim and softwood floors, and if that holds up, I can't think of any reason why 2x4s shouldn't.

But old New England construction lasts because it's maintained. New roofs, new clapboards every 50 years, regular painting, interior repairs and renovations. With land costs what they are in many regions, it's cheaper to take care of a good house rather than just letting it fall apart over 50 years.

Large dry laid stone can easily last thousands of years as long as the foundation is solid. Consider the pyramids both in Egypt and South America plus a host of other very old structures. However, you need to avoid tension, earthquakes, and unstable ground, can’t build very tall etc. High construction costs, slow build times, and serious limitations in what structures are viable shows just why we mostly abandoned the technology.

Mortar is basically indefinitely replaceable with constant maintenance and has lower upfront costs. So it’s generally a much better option.

This has been a big issue with stainless steel climbing anchors and hangars, as it leads to sudden catastrophic failure with little warning, as you don’t get rust like normal steel. Some areas near the ocean have had failures in as little as 5 years - faster than if they’d used normal steel.

The coatings were super fragile, and often damaged while being placed in the field. Then someone had to come along with magic paint and touch up all the cracks. But of coarse they would never find 100% of them...

Just different materials, with different performance profiles, that you can use to beneficial effect in different environments. But you have to know and understand the implications of the different performance profiles.

I'm not going to do a whole engineering lecture here, but there is a really good concrete nerd who can outline this, and so much more, for you on his youtube channel if you're interested. He's a good engineer and I've been impressed with the accuracy of the material he presents as well as the accessibility with which it is presented.

Tyler's channel: https://www.youtube.com/channel/UCrvfiHNDS_QI-FgKQSmTITQ

More detailed explanation of tensile strength implications in structures: https://www.youtube.com/watch?v=thUZImUTZn0

But is that something we're trying to build? As the saying goes, it takes an engineer to design a building that's barely standing.

We know how to build stuff which lasts for centuries, there's plenty of those lying around in the old world.

Indeed, I see the opposite. I see advocacy groups that are fighting against single use plastics using anti plastic straws campaigns as a way to spark conversations about other kinds of single use plastics.