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Comment by rcarmo | Hacker News Reader

Living in a country where pretty much _everything_ has been built out of brick/stone/concrete for a long while now (with clay shingles), I find US building codes to be baffling.

Not criticizing, mind you, since clay shingles are still supported by wooden beams in older detached homes and those go out too in forest fires (which we also have, on a yearly basis and with tragic results) - I just don’t get the rationale for small homes to be built out of wood these days - is it cost?

(Edit for typos)

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The West Coast of the US is prone to earthquakes, and wooden structures survive earthquakes much better than brick structures do.

(They're also quite a bit cheaper.)

Wood framed buildings are much, much safer in earthquakes and with plywood shear walls can be considered the very safest construction method.

Aesthetically, I dislike it because I have a taste for very solid, permanent things, but if you live in California, stud-wall ("stick built") construction with plywood shear walls over them is really the only choice.

A wood house can be permanent if you get the moisture management system correct.

Americans don't believe me when I tell them my relatively recent regular UK house is built out of brick!

They say things like 'it's a wooden frame with a brick facade, right?' or 'I'm sure the supporting structure isn't brick.' No it's brick. It's all brick. The walls on all sides in every room are about 30cm of solid brick with plaster directly on top. Even the internal ones.

If you want to run a new light cable or something you'll be using a hammer and chisel to make a channel to put it in.

I don't think you could do this in California due to earthquake-related parts of the building code.

In the Christchurch earthquake in NZ, bricks were deadly. And Christchurch "didn't" have a faultline.

Also houses made from brick have a lot more damage in an earthquake - the mortar cracks and the structural integrity is lost.

That said, it was mostly older brick premises, chimneys, and facades that caused deaths. "Falling masonry killed 40 people in Christchurch's February 2011 earthquake"

Yeah, a brick house becomes a sandcastle in an earthquake.

We had the technology to build earthquake-proof houses for quite a while without needing to use timber framing which has all kinds of downsides.

http://dme.engin.umich.edu/stubbornstructures/

The only advantage is cost and speed of execution, they call them McMansions for a reason.

Timber also has its upsides, including locking up carbon, and being easy to modify after the initial build.

Locking up carbon? The trees are produced / harvested according to demand, no? I think I may be misunderstanding your point in noting this.

Trees are made of carbon. Growing a tree takes carbon from the atmosphere and turns it into wood. When you build a house out of the wood that carbon stays in the wood for the newer few hundred years rather than going into the atmosphere, so staying ‘locked up’.

Dry, moisture-free wood is about 50% carbon by weight.

So if the panelised timber frame superstructure for an rectangular two storey house of 150m2 is approximately 14 metric tonnes, you're locking up 7 tonnes of carbon for the life of the building (minus of course the carbon emitted to plant, prune, fell, transport, mill, treat, get the wood to site, install it etc.).

If you can use more timber through the construction, all the more effect.

Doesn't the same amount of carbon stays locked the same in a tree in the ground? I don't understand why building with wood helps in this case. There's plenty of space to grow more trees...

There's not an infinite amount of space to grow trees actually. A decent forest needs the right climate, water. Economically forestry must compete with other land uses such as grazing, orchardry, etc.

It takes pinus radiata about 25 years to reach maturity. Then it can be turned into buildings/ houses, and the carbon locked up in that structure, which can be e.g in the city or suburbs- somewhere there will never be suitable for forestry.

And then the forest can be replanted and the virtuous cycle begins again.

tldr; locking carbon up in timber gives more flexibility than just relying on standing forests.

If you’re buying the wood then someone is being paid and incentivised to plant more trees to sell next time.

Outside the warmer areas of the US, I think a big reason for wood framing is how easy it is to insulate.

I'm not sure how it's done in the UK with brick buildings though. It seems like if you needed much insulation you'd end up with an inner wall and brick facade.

Two layers of brick separated by an air cavity in the old days (c. 1970) and more recently with foam, glass fibre, or rock wool.

UK: Breeze block inner, cavity with rock wool and brick outer with internal walls of basically studding with plaster board for my 1985ish 'compact and bijou town house'.

Some medium-rise blocks of flats use steel frame floor plates from concrete central pillars with external cladding approach but most new houses are brick.

Partially and historically the US has had a lot of wood, the UK deforested early (we built a lot of ships and wooden structures) so we had to go to brick and slate quite early (also our climate is hell on wood without modern treatment).

Also the US climate is far more varied than the UK's so in some biomes wood makes sense.

A lot of the interior West and SoCal where fires are the most intense is unforested. A good deal of the lumber used to build is shipped in from elsewhere.

My home state of Idaho (the south) is largely cheatgrass, tumbleweeds, and sagebrush. None of which are useful for construction. All extremely flammable most of the year.

Not sure where you're from, but cheap lumber, bro. California has lots of forests, and therefore timber framing is comparatively cheaper here.

Most (all?) California residential including apartments are wood framed for earthquake survivability of the residents. https://www.nytimes.com/1999/01/31/weekinreview/the-world-on...

Reinforced concrete frames are also earthquake resistant and fireproof, e.g. popular in Greece. Search "Eurocode 8" for reference.

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