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Comment by coldbrewed | Hacker News Reader

Modern building construction is cheaper and doesn't demand old growth timber, but it's also much less resilient during a house fire. We use smaller dimensional lumber, it has less densely packed tree rings causing it to burn faster, and we use I beams made out of 2x3s and OSB instead of solid lumber. A house made in the 30s could survive a long time before collapse in a fire; what we have now collapses much faster.

There are definite benefits to modern techniques that are less resource intensive and protecting our remaining old growth forests is important, but we're sacrificing a lot of valuable properties as well.

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We've more than compensated for this in other building materials, processes, and codes. Your odds of dying in a house fire are far lower than they were even in the 1970's, let alone the 50's or 20's.

That's probably more because of smoke detectors (and perhaps fewer smokers) than anything else. I'd love to get a sprinkler system retro-fit though, as that would make an impressive difference.

All the lighter-weight joists made with OSB burn far faster than the 2x8s or whatever they replaced, and home furnishings are made with large amounts of flammable synthetics.

At a live-fire course I was on, the scenarios we worked on were fueled by stacks of wooden pallents, lit by an instructor's tiger torch. One of the instructors asked us if we knew the fuel equivalent of a typical love seat with synthetic foam, in pallets. We all figured it was lots, but not the real answer: NINETY.

They've done the research and, well, the newer houses really are just better at having fewer fire deaths. I suppose it's possible the fires that do occur are worse, but on net your death rate is lower in a newer house.

https://www.nahb.org/-/media/NAHB/advocacy/docs/top-prioriti...

> As expected, the coefficient estimate for the percentage of houses built after 1989 (pctpost89) is negative and statistically significant. This implies that, in counties with newer housing stock, all else equal, the fire death rate is lower. Interestingly, when identical regressions to model 1 were run using different cutoff points for new stock, such as the percentage of houses built after 1979 or 1969 or 1959, the coefficients were of roughly similar size, were always negative, and the associated t-statistics were at least as significant.

Interesting paper, thanks. It does make some of the same distinctions I did, around smokers and smoke alarms. Another thing mentioned about newer construction is the improved blocking and stopping. For example, one old style of framing was "balloon frame" construction, where you would have gaps that might run vertically from basement to attic. That gave fire a channel to rip vertically through a structure, and is clearly a terrifying idea once it catches. [Edit] Oh, I forgot to mention, it also discusses what conclusions can't be inferred. "Regrettably, much of the available data is not helpful. For example, no data are collected on the age of the structure where a house fire death occurs, despite the obvious link between the two."

The starting point of this though, was the idea that the materials in the house are actually better than in the past. To the extent that they'll tolerate fire longer before collapsing, they aren't, and the gases from the foam cushions, carpets and drapes are more toxic than ever. The reason this was drilled into our heads is that it means less time to get into a fire, and someone out, before we all have to leave for our own safety.

> Your odds of dying in a house fire are far lower than they were even in the 1970's, let alone the 50's or 20's.

I am very surprised by this.

I'm sure that building codes ensure that the actual houses are more fire resistant. And fire fighting has probably come a long way.

But the typical home is full of processed plastic fabric. Which burns a whole heck of a lot faster than either cotton or wool. Carpet, curtains, clothes, furniture, etc.

I am sure smoke alarms make a big difference and people not smoking. Circuit breakers instead of fuses. Plus all the for fire exits and fire doors in apartment blocks.

Perhaps, but I'm not sure I live swimming through an invisible ocean of fire retardant chemicals that are in all home furnishings and most clothing and so forth. I'm not exactly a California Prop 65 fan, but I do wonder if those are anything any sane person wants near them.

Also, in Japan, they are requiring old growth timber for home construction in certain northern areas for earthquake resilience.

The reasoning is that old growth lumber handles repeated compression better as they are denser, harder, and firmer. New growth timber is squishier due to it being softer with less tightly grouped growth rings.

At first I thought that made no sense, then I realized building a house out of sponges is not ideal. Fighting collapse is sometimes more about rigidity in the correct place rather than absorbing all shakiness everywhere.

Do new building codes account for this? Even given the worse materials, I would expect a house built today to be much safer (from fire, hurricane, tornado, etc.) than one built 100 years ago.

Yes. We now use engineering standards to design houses. Looking at 100 year old houses as an engineering is enlightening (you don't even have to be a good engineer, just look and think). Old houses are often way over built in places where there is no stress and so paper would work - but those places are visible. Meanwhile places that do matter are often under built and it is amazing they are still standing at all - but those places tend to be not easily seen. Which is while people say modern houses are built from cardboard - in many ways they are - but those are all places where strength isn't needed so why waste money.

What you won't see in the above is things that are hidden. Modern code requires you to have a firestop in all walls every 10 feet - old houses were often balloon framed which means the inside of the walls becomes a chimney in a fire and will help feed the fire. New houses the inside of walls do not become a chimney because of that fire stop.

Modern houses also are insulated to much better standards. Something else that often isn't seen but makes a big difference. Even when it is seen nobody thinks about it - those old windows the article is singing the praises of are universally single pane windows that should have been scrapped 40 years ago. Sure there frame is still like new, but the standards for new back then are not acceptable.

The bigger lesson to take from the above: don't build to last too long. What people want out of a house changes over time, and you never correctly anticipate what people will want in the next decade. Eventually that old house will have enough things "wrong" that cannot be retrofitted and the best thing to do is tear down and rebuild from scratch to modern standards.

> The bigger lesson to take from the above: don't build to last too long.

Disagree.

Build to last long, but accomodate modification.

Old houses are built to last a very long time, because they weren't commodities being bought and sold on a 10 year timeframe. But old houses are also very difficult to modify. As you noted, no structural engineering, also lathe & plaster walls are a nightmare to take down, etc. etc.

I don't know which houses you're referring to... or maybe you're conflating survivorship bias with quality... but old houses most definitely weren't built for "a very long time". Even fancy mansions from 100-200 years are all but falling apart in most countries across the world.

I live in a house built before structural codes were made mandatory(1964) - and just yesterday we had to replace a third of the true 2x4s because they were rotten and a corner of the house was liable to just come crumbling down.

If you want more proof - look at the remains of civilizations that built primarily from wood... but there isn't much to look at at all!

You commented further down mentioning "siding", but if I'm following this conversation correctly many of y'all are talking about different periods of construction as if they're all the same, or even linear in quality over time.

For instance, timber framing is a very old practice and the beams used are so thick they do indeed last hundreds of years. However, timber framing refers to the structural beams themselves, not fascia like siding. You could still use OSB and new growth finger boards to do the non-structural framing, and many modern houses do.

Then there's houses like mine from the 1950s. They use solid maple beams, but oak and elm are also common to that time period. They're structurally more load bearing that way. Unlike timber framing they take advantage of both proper joints and things like hangers.

More modern construction doesn't really do much jointing from what I've seen, but I may be wrong or have a limitation of exposure here. They rely mainly on structural forms like hangers.

I'm not sure that any one is better than the other. They do have different considerations though. A timber frame is going to be tough to modify once it's stood up. A house like mine will probably also be tough to modify, but they could by introducing forms. The newer homes are probably the easiest to modify, but probably are somewhat weaker than the frames of my house. Strength like that doesn't really matter until it does, though, imo.

Water intrusion is a maintenance problem, not a quality problem. The old growth framing in my 1950's house feels like it will last forever.

If you have to replace your siding wholesale every 20 years to prevent water intrusion - you're not building for "a very long time".

Selection effect here. Plenty of old houses weren't built to last. You just don't see them anymore because they're gone.

> What people want out of a house changes over time.

Hard disagree. At it's essence, a house is a shelter from the environment. The need for walls and a roof doesn't change.

Engineering a house for longevity isn't hard, all that really matters is water/moisture management.

Any "wrong" things with a house can be fixed. There are very few houses that are unsafe to inhabit and require a rebuild.

A house is so much more than a shelter from the environment. If it were, people would live in garages made of metal plate.

> Any "wrong" things with a house can be fixed.

Fixing anything can be done / is possible. That doesn't mean it is the brightest idea to always do so.

Modern wood houses have very poor noise insulation. I grew up in a brick house. When I came to Canada, and I found I had to keep my voice down at night, while speaking in a closed room was news to me. Not only can other people in the house hear, but so can the neighbors! I don't know how people live like this.

> Modern wood houses have very poor noise insulation

I agree, but this doesn't have anything to do with the woodenness of the construction. Virtually all interior walls in your typical North American single-family home, built with wood or not, are lacking insulation. Code doesn't require it, people don't want to pay extra for it, and builders don't want to convince people to spend the money for it.

That is mostly wall mass and engineering, not anything to do with the use of wood. I have lived in very quiet wood buildings.

Noise isolation is mainly about adding mass. Thermal insulation is mainly about creating a continuous skin and filling the void with something as close to a vacuum as you can get.

Home insulation doesn’t work by making walls close to vacuum. You insulate walls by stuffing more (but not too much) of stuff into them, not by pumping out air or anything silly like that.

Vacuum is a great insulator, because it blocks two fastest ways of heat transfer, conduction and convection, leaving only radiation. House insulation tries to do the same thing: filling up the wall with fluff blocks air from moving around, which impedes convection. Fluff itself is made from materials of low thermal conductivity, like cotton or mineral wool. At the end of the day, though, filling walls with fluff makes them less like vacuum, not more.

> The bigger lesson to take from the above: don't build to last too long. What people want out of a house changes over time, and you never correctly anticipate what people will want in the next decade.

Probably even more applicable to software projects!

Maybe, but most software projects isn't designed for as long as things will last (I'm not sure we even know how to do this!). It is best to think of software as under continuous remodels. Very few houses survive for 40 years without a major remodel - adding rooms, moving walls. (much less "minor remodels" like replacing the kitchen cupboards - and the paint will not last for 40 years no matter how hard you try).

If you continuously remodel your house like software is, then by the time it is 50 years old there should be zero original walls left. But software is a lot cheaper to make changes to.

"The bigger lesson to take from the above: don't build to last too long"

In the world of the Rich Third World, houses are almost always torn down after they're bought. It's actually pretty bad, because those houses are always built to last...but they only really last for about 8-15 years on average. Then it's almost always easier to rip and replace again instead of renovate, because they're built with concrete.

Even something as simple as granite countertops are a good example of that. A stone countertop is hundred of thousands or millions of years old. They would likely last until the planet itself was swallowed up by the sun as it swells with age.

But, granite countertops installed in the 90's and 2000's are considered "old" and "dated" and are being torn out for a different stone often at great expense.

It was a waste that they were ever installed to begin with. Could have installed a laminate countertop that would last 5ish years and look good for 1/10th the cost and then swapped it out 5 times in the same time period for a fraction of the cost and essentially no permanent waste.

Granite countertops sit on top of wooden frames. They're as long lasting as the wooden frames underneath.

> Do new building codes account for this?

Yes. Survivability to fire is explicitly listed as a requirement, and different classes of buildings have strict requirements on survivability (i.e., how long a structure must remain safe while subjected to a fire).

> I would expect a house built today to be much safer (...)

It is, but there are nuances. For example, modern houses have additional requirements on energy efficiency, which mean thermal insulation. Elements used in thermal insulation applications are regulated, but it turned out that some assumptions regarding flammability ended up not being met under some circumstances. Consequently, we've started to see a few incidents such as the Grendell tower fire.

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

Another event was the much recent fire in a Spanish residential complex.

https://en.wikipedia.org/wiki/2024_Valencia_residential_comp...

> Do new building codes account for this?

Yes, we have code about fireblocking, minimum insulation in wall cavities, etc. for that.

Structural code also updates with wood quality testing. In structural charts I've seen, old growth is around 3x stronger for the same size as newer SPF. It's about on par with an LVL product.

Iirc sprinklers are now required in homes in many areas.

And homes are much more resilient to other forms of damage, like actually having to be bolted to the foundation instead of just resting on it, etc.

Metal brackets and hangers required in new construction make new houses much stronger

Do those brackets and hangers make up for the particle and pressboard my stairs are made out of?

Seriously, they could have come out of a flatpak. I assumed cost cutting, because the risers are a different board than the tread.

Using the same material for load-bearing and non-load-bearing parts seems like the definition of overengineering.

Those metal things they use to hold prefab trusses together are hated by firemen, because once it starts burning they just curl off and the strength is gone.

Comparing homes today with that of 100 years ago ignores the fact that in many ways housing quality has been on a decline since the 1970’s due to cost cutting and lazy workmanship from large scale contractors.

In my city, we have entire communities of the city that people avoid buying homes in because of shoddy workmanship.

Greed corrupts and it has hit like a plague in many large neighbourhood projects over the decades.

You can have all the codes in the world, it doesn’t matter if no one follows them.

The 1970s were about the worst of that. While cost cutting has continued, engineering is more involved in standards and so the cost cutting is not possible unless engineering determines that the cost cutting doesn't effect something important.

Note that what you think is important to lay people and what engineering thinks is important are very different things. Engineering cares about fire safety, insulation, and your house standing up to wind. Engineering doesn't care if you kick a hole in your walls - that is your own stupid fault (engineering cares that you cannot get pushed through the walls cartoon style, but a small hole is not a problem). Laypeople often reject great engineering because the marketing on bad engineering is better - old houses is one of those cases.

In some places, the problem is that scammy builders are not building homes to spec.

I'm talking about very serious flaws: not like drywall being thin, but more like joists that are thinner than the engineer specified or incomplete flashing that lets water leak into the insulation whenever it rains.

A few years ago, I worked in a brand new building, and we had issues like windows being installed inside out, pipes not being connected together, and rainwater trickling down walls under the paint.

These builds are poorly engineered -- not by the engineers and architects, but by the builders ignoring the engineers and architects. You can see numerous egregious examples here, for example: https://m.youtube.com/@Siteinspections

Yeah, this is what I’m referring to. It doesn’t matter if you have codes if people don’t follow them because of laziness and corruption.

I’m getting down voted, I guess I touched a nerve of the civil engineering folks.

I came to the knowledge I have from having discussions with my civil engineering friends. They were immediately disenfranchised a few years into their careers when they saw the corruption of the “construction cartels” in my city.

I’m sure it’s not true of every city, but it is in the city I live in here in Western Canada. Also common elsewhere in the world.

Yes, thank you for speaking to the reality on the ground, which a lot of folks in these comments are pretending doesn't exist. We have standards and codes, but I've worked on many new construction sites where nobody gave 2 shits about what, how, or why. They threw shit together, and as long as it looked close enough, it even passed inspections (always another job site to go to after this one after all). I personally know of many $1 Million+ houses in the Chicago area, that house some very shocking surprises inside their walls.

I don't think it's just the marketing. As you said in your earlier comment, old houses overengineer things that are visually obvious to the homeowner but not of actual safety importance. Humans are very susceptible to this visual bias. As you say, they're not inspecting fire stops, insulation standards, sprinkler placement, etc.

Old growth lumber takes longer to start burning but once it takes, it going to be a hotter more resilient fire.

I mean, by the same logic, you could say every house should be built from steel. Of course old growth is stronger, just like steel is, but using them for the majority of cases would be simply ridiculous at scale.

> but it's also much less resilient during a house fire

Mass timber and other new engineered products should be good for this.

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