[RoadieRoller]

(I am not a US citizen, but visited many times) Why not build houses using concrete/cement? Poor Asian countries have been building houses for decades using concrete and less maintenance. No, it is not about weather. Concrete can be easily used in Southern US states where winter is less than a month or no snow at all. At least the structure can be concrete and the walls be wood or drywall. I think it is the wood mafia trying to make a living out of enforcing city codes to use only lumber for houses.

[mywittyname]

Costs.

The type of lumber used to frame American houses is (well, used to be) quite cheap. Concrete is like $10 per cubic foot. While, a timber framed wall is mostly air. An 18x8 foot wall made of timber would take about 16 boards to make and take an experienced team less than 20 minutes to put up. That's $100 or so in material costs at current (extremely high) prices, plus maybe $100 in labor (this is pretty hard to estimate, actually).

That same wall would be like $700 if made from concrete. And labor costs would be probably equally as expensive because those forms take a long time to assemble. They need to be shipped in, assembled, left to cure, disassembled, then hauled away. While lumber just needs to be dropped off the back of a truck into a pile in the yard.

[wearywanderer]

Poured concrete will often use a lot of lumber anyway, since the concrete needs forms to be poured into. However, using precast concrete or CMUs avoids this.

[saltcured]

Another type of concrete construction in parts of Asia uses prefabricated, reinforced concrete members. Piers, beams, and panels with internal steel made in a controlled factory setting and having high strength. It's a bit like half-timber construction but replacing the thick timber with concrete. They also use similar concrete for telephone or neighborhood power poles.

They are brought on site and erected by cranes and pile drivers to build the frame of a house somewhat like with large timber. The panels are set across beams to fill in floor areas, and walls are closed with non-load bearing elements, whether brick, blocks, stucco, drywall, etc. I am not sure how well this method works for seismically active areas though, where you would need to tie those in-fill wall areas into the structure.

[bobthepanda]

Also, a lot of home construction in the US is single family and this type of construction is by and large mostly wood.

Concrete is used as a base for apartment (like four or five over two) but wood still makes up the majority, and there aren’t a whole lot of residential projects in the country built as massive concrete tower blocks outside of some specific regions.

[danans]

> Why not build houses using concrete/cement?

Partially because until recently, wood was the most plentiful and cost-effective building material in parts of the US. It is far more seismically resilient than brick or concrete.

It is also much easier to modify if you want to add a window or other opening - cutting an opening in a concrete or cinder block wall is much harder.

Wood, when responsibly harvested, also sequesters C02.

That all said, it's possible we'll see an uptick in the popularity of alternative structural materials to wood - but traditional concrete has an absolutely massive carbon footprint, and low-carbon and low cost concrete alternatives aren't readily available on the market at this time.

[bobthepanda]

There have been recent developments in wood skyscrapers for the benefits you mentioned, so I would bet wood only gets more popular.

[ericmay]

We don’t even need to build those at all… let alone with wood.

[bobthepanda]

We don’t need to do much of anything, but tall buildings are fine, given that they minimize the land impact of a given amount of square footage, and denser communities have lower land footprint and lower per capita carbon emissions.

(European cities are plenty dense at moderate heights, but they also offer much smaller living quarters than American ones; a Parisian studio is in the range of 9-35 m^2 whereas an average Manhattan studio is 51 m^2, and most Americans would consider it small.)

[ericmay]

Skyscrapers specifically (tall buildings depends on definition of height), but they’re very energy intensive. You can only operate, construct, and maintain them with cheap oil.

The problem isn’t density (most European towns are perfect here actually) but too much density. Manhattan is the opposite spectrum of suburbia, and neither are very desirable. France actually does this well in Paris, as you mentioned. The American thing to do would be tear down every arrondissement and replace with skyscrapers. Paris sort of made that mistake with part of the city before they stopped.

I have to imagine that it's not that skyscrapers are great for emissions, but that the suburbs are just abysmal and so everything looks good in comparison.

Walkable neighborhoods and bike-friendly development in mixed-use medium density areas is probably the best. The main issue with suburbs is that you have to drive everywhere, not necessarily the density.

[bobthepanda]

Operating them is not that expensive. A building's heating and cooling needs are proportional to surface area, not volume, and in a given apartment building the vast majority of walls are shared with other units instead of outside. So a taller building is more and more efficient with regards to climate control, unless it doesn't contain a whole lot of volume. The Burj Khalifa is obviously not ideal but at least judging by, say, Hong Kong the optimal sweet spot for a building is 30-40 stories, where you're not running into massive extremes of either cost or carbon emission.

The reason the suburbs perform so poorly is, among other things, transport very quickly becomes the largest contributor to emissions. Hong Kong is so dense that not only is the "fifteen minute city" more than a reality for non-work trips, but most people are within a 15 minute walk or bus ride of massive shopping malls with department stores.

That being said, the end picture looks fuzzy after some more searching, mostly because it's hard to isolate variables about cities (their wealth, their climate, etc.) and also because the definition of what a "city" is varies globally. Other than "very car oriented suburbs with large lots and home sizes are big carbon emitters per capita."

[hwbehrens]

It varies between regions, but in general, building with wood is significantly faster and less expensive than using concrete. They are also easier to remodel, extend, and ultimately demolish, but these are secondary reasons.

Some areas, such as regions of Florida or Arizona for example, have substantial historical housing stock made from concrete. However, the majority of new construction is wood for the reasons stated above.

There are not (to my knowledge) any building codes that prohibit concrete construction for residential.

[gresrun]

At least in FL, slab-on-grade with concrete block for the first story + wood frame for additional stories is incredibly common because it is far less susceptible to termite & moisture rot damage than slab + wood frame or wooden pier + beam.

[spideymans]

Environmental concerns are one reason. Concrete is more environmentally intensive than lumber, and the construction industry already accounts for a significant portion (about 10%) of global GHG emissions. We should be moving away from using concrete when more sustainable alternatives exist.

[jandrewrogers]

Two reasons: cost and earthquakes.

The US has vast timber forests, so it is inexpensive, and timber (or steel) framing works well for earthquake resistant construction. A large part of the US is a seismic hazard zone and the building regulations reflect that. You can find older neighborhoods with unreinforced masonry throughout the US but those date from a time before they had modern building regulations and before the extent of earthquake risks were fully understood.

[clusterfish]

It's more expensive and has a terrible environmental impact. Forestry at least can be sustainable if done right

[sorenjan]

According to this article [0], cement is the source of 8% of the worlds carbon dioxide emissions. Switching from renewable materials like wood to carbon emitters like concrete is not what the world needs right now.

[0] https://www.bbc.com/news/science-environment-46455844

[MattGaiser]

Americans tend to want very large homes by global standards and lumber is (or at least was) cheaper.

[dotcommand]

> I think it is the wood mafia trying to make a living out of enforcing city codes to use only lumber for houses.

Not really. No more than the ice mafia made the inuit build igloos out of ice. People do with what they have. The eastern seaboard is chock full of trees. When the settlers arrived, they used what was readily available. It's far easier for settlers to make homes out of wood than stone/rocks/etc and concrete didn't exist back in the 1600s/1700s. And as the borders of the country expanded westward, the style of homes made its way west as well.

[kenned3]

My ex-wife is Chinese from a city in China where everything is made out of cement.

The reason? The region also lacks trees. They have an abundance of the raw materials for cement, but not wood.. So that is what they used.

Cement is also a terrible material for many climates. Here (ontario) the freeze/thaw cycle causes it to crack unless you use a lot of costly methods to prevent this.

[bcrl]

Portland cement has a significantly worse environmental footprint than wood. One removes carbon from the atmosphere while the other releases it.