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Comment by LeifCarrotson | Hacker News Reader

As an American, how else do you build houses? Solid concrete? That seems a little ridiculous, especially for interior walls...

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The 1920s ex-council house I live in is built from two layers of brick separated by a cavity (with metal ties between the layers, which are themselves a problem because they rust). Unbelievably even the internal walls are also all two layers of brick. All I know is that labour must have been very cheap in 1920.

The outer cavity is designed to stop water from crossing from the outside to the interior.

There is a fashion for filling the cavity with insulating materials, but that leads to problems because it can draw water between the layers.

My 1959 red brick construction house in Tucson, Arizona is built the exact same way, but for heat control in the summer.

I also own a rental house that is 100 years old made of 14" thick mud adobe walls, including the interior walls! Also done for temperature control.

Bricks, in the majority of the world for the last thousand years. Making interior wall with plaster or wood is illegal in some european countries.

Bricks have very low r-value meaning that you pay a lot of money to heat/cool them. Bricks is a bad choice for construction anywhere where indoor climate control is an issue.

American construction is strong enough to last for a few hundred years if you maintain it. While it isn't passive house efficient it is efficient (and it isn't clear that a passive house is even possible in our climate - many of them make other compromises which means they rot out in a few years).

Wait, what?

How can you know about r-values but not that every modern house built has cavity walls that can be/are insulated?[1]

Even hundred-year old houses can be insulated by DIY drylining. You'll lose about 10cm of floor space though. Sometimes there's even some government grants available for this[2]

[1]http://www.residentialenergydynamics.com/portals/0/Resources...

[2]http://i.telegraph.co.uk/multimedia/archive/02041/jeff-howel...

I'm biased to US construction methods of course. Note that while bricks are themselves of a worse r-value than wood, but wood isn't actually a great r-value either.

Note that bricks are not a strong as wood under tension. They do well under compression, but that is not all the loads to account for. Bricks are used in cities and commercial construction primarily because they do not burn and so you can use them as a safety barrier.

Not usually concrete in a domestic house, but solid red brick or stone blocks for the internal walls yes. Hollow walls like a kind of wood and plaster tent seems just as ridiculous to me. Solid walls keep the house cool or warm and stop noise.

New construction (at least in the north central US) is minimum 2"x6" studs in the exterior walls filled with fiberglass insulation and pretty significant blown fiberglass insulation in the roof. Most of the noise going between interior rooms is a result of the use of cheap, hollow doors; usage of solid oak doors minimizes sound travel between rooms. Additional noise-damping insulation can be installed between rooms if desired that effectively eliminate all sound travel between rooms.

I'd speculate that a well-build modern wood-and-sheetrock house is probably more energy efficient and quieter than an early 20th-century double- or triple-brick house.

Also, wood-and-sheetrock is a lot easier/cheaper to replace than brick when a tornado comes along and knocks the house down, which is possible in 75% of the US.

There are significant areas of the US where I suspect it's actually illegal to build an all-brick house (as opposed to just quite expensive).

The UK is basically tectonically stable, which means those brick houses aren't likely to collapse into a multi-ton pile of bricks when the mortar crumbles or cracks in an earthquake. The same cannot be said of many areas in the USA, and it only takes one earthquake every few decades to drive that point home.

No, please no concrete for the walls. I have lived in an an apartment that had concrete walls in Bangalore and it's just terrible. Concrete amplifies both hot and cold weathers. So you are spending a ton of money on air-conditioning and heating as well. Admitted, in Bangalore you don't need heating but I can't imagine a concrete house in the northern hemisphere. Like others have stated, solid bricks, stones or even clay bricks are a better alternative. You still need to use cement but that's alright.

Concrete walls are rare in Bangalore. Cement bricks seem to be common these days.

Even until a few years back it was all clay bricks.

Agree with you. Full concrete homes are basically the furnace and freezer experience.

The thermal mass in construction is like adding inductors and capacitors to a circuit. It has to be tuned to the local climate. The best you can do with thermal mass alone is an interior that is always the local mean temperature (like in a cave).

So in a thermal wall, you should match the rate at which heat conducts through the wall to the thickness of the wall, such that it takes about (12 + 24n) hours for heat applied to the exterior of the wall to radiate from the interior of the wall, and vice versa. You're trying to eliminate the daily temperature variation, so that the heating or cooling load will be more stable.

Adding phase-change materials to the concrete mix would help, but for the most part, the traditional building method in the region has been tuned by trial and error. If you build an adobe house in New Mexico, you make the walls from local materials, with the same thickness as the traditional homes. Or you get an engineer to do the thermal calculations.

Most houses built in the US just stick to the building code, which is generally good enough to accommodate local weather conditions without breaking out the calculators.

Right. Writing code to estimate the optimum thickness was one of our homework problems in modeling and simulation class, back in the day. I expect running that sim on a PC would be trivial today, but back then it took a significant amount of time on a fast SPARCstation.

(the basic idea was to model the wall as extremely thin slices so the heat transfer between slices can be approximated easily. How thin? You kept making them thinner until the model stabilized).

The wall thickness we derived was very close to the wall thickness traditionally used by the indigenous people of the area. What are the odds? :-)

Possibly the difference he's noting is using wooden studs vs. metal studs? which definitely feel more hollow.

No, literally all the internal walls in my house are built from two solid layers of red bricks. There's no wood or metal involved. This is normal in most of the west outside America.

Oh, ya not sure if I've ever even seen that. I live in an old (by American standards) 1950's apartment building with plaster walls, but pretty sure still hollow underneath.

Seems like that would make it harder to frame a new subdivision in under a week.

Yes you can't slice-and-dice it like I'm sure you can wood. But they last forever. Houses here are routinely hundreds of years old where in the US the approach seems to be to knock down the wooden houses and build them again before they get that old.

> But they last forever.

At least until the next earthquake, which is a real possibility in much of the US. Light frame houses survive earthquakes pretty well. The brick chimneys on them don't.

> Houses here are routinely hundreds of years old where in the US the approach seems to be to knock down the wooden houses and build them again before they get that old.

Well, yes and no. The US isn't that old. There weren't a lot of homes here hundreds of years ago so obviously there aren't a lot of 200-year old homes now. But yes, there's also a fair bit of demolishing of 50-year old homes.

I live in a four-story condo building that's about 100 years old and entirely wood-framed, all the way down to massive wood beams in the basement that anchor the entire place to the foundation. There's been some moderate renovations of exterior walls because of water damage before, but it's worth the hassles of that kind of thing to know that if an earthquake comes along the building will ride it out without any serious damage.

> There's been some moderate renovations of exterior walls because of water damage before

Yeah, I don't understand the comments in this thread that talk about water damage. Do people in Europe just not bother maintaining their roofs? You can get hidden water damage from a leak into a hollow wall, but it's really not that common. Typically there's visible water staining and severe damage only comes from willfully ignoring that signs.

I know plenty of people with houses over 100 years old in the US, so it's not like the houses aren't lasting that long. Naturally, it's not as large of a portion of the houses as in the UK because the US's population has more than 200% in the past 100 years while the UK's only went up by 50%, so the US needed to do a lot more construction since then.

Brick is very dangerous in an earthquake.

This. You wouldn't catch me in a brick house in Northern California.

Or even in the midwest.

https://en.wikipedia.org/wiki/New_Madrid_Seismic_Zone

It's going to be an ugly, ugly thing if another major quake hits there. The last time the region was sparsely populated. Now there are cities all over the place and and the seismic codes are far more lax than they are in California (if said codes even exist).

Full brick :)

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