It's reused immediately as a waterproofing membrane.

Well concrete is not waterproof (generally) so they are technically also using the form as waterproofing. It's pretty clever IMO but you'd need rebar at the very least for any structure worth building...

Concrete construction without rebar is more durable and worth bringing back.

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

How well does it handle earthquakes?

It doesn't.

Earthquake resistance is increased by strengthening the concrete, but it mainly depends on how the structure is built, not just the shape but additoinal measures used to strengthen the structure. We've been stuck on rebar for so long that research on alternatives has stalled, but there are interesting opportunities and developments in that area. For example, basalt fiber and bamboo have potential.

Sustainable, innovative building structures that don't require energy-intensive and corrosive steel will depend on a convergence of strengthening technologies and archtectural techniques, maybe even including ones like described in the original article.

Considering all the environmental and social problems we have with modern housing and construction, this is a prime area for innovation!

https://www.architectmagazine.com/technology/two-natural-reb...

Isn't there a massive difference in wall thickness between what the Romans did and what we do today?

Modern uses of Roman concrete go beyond what the Romans did. We can create completely different types of structures using the same principles. Here's an example of recent developments in research:

https://www.sciencedaily.com/releases/2021/01/210113090920.h...

Concrete without rebar lacks tensile strength, and Roman concrete is no different. When using materials with insufficient tensile strength, you're severely restricted in the kinds of structures you can build. That's why Roman buildings used so many domes and arches, and why they were massive.

Practical Engineering has a good video about it: https://www.youtube.com/watch?v=qL0BB2PRY7k

It seems like a high amount of complexity. Lots that can go wrong.

I’ll take tyvek and wood :)

Concrete is also super bad for the environment. Wood is renewable and far easier to get locally.

Good website: https://www.thinkwood.com/mass-timber

Another good website: https://structurecraft.com/materials

Insulation might be nice once it gets chilly.

Even worse, it becomes the inside and outside vapor barrier for the entire house. An air tight home lined with phthalate-laden PVC? No thank you.

Dangers of pthalates notwithstanding, you do actually want an airtight home. Ventilation should be controlled and filtered with the HVAC system.

Now, I'm from a place where HVAC is rare, and thus this sounds like a mold disaster waiting to happen. But is that actually best practice where HVAC is common?

A modern, energy efficient house is intentionally very air tight, and ventilation is achieved using mechanical ventilation with heat recovery. That basically gives you the best of both worlds - a highly ventilated house (so low humidity levels) coupled with very little heat loss - MVHR systems can often recovery 90% of the heat in the ventilated air.

Look at Passivhaus for the most extreme version of this. But even regular new build houses in the UK now have to meet air tightness regulations.

Ventilation is not HVAC. Ventilation can be as simple as having openable vents at proper locations in a structure which could be manually operated to provide air exchange on demand.

> Ventilation is not HVAC.

That 'V' in 'HVAC' must have an industry-specific meaning beyond "Ventilation" then.

Ok, let me say it more precisely: You can have ventliation without an HVAC system.

For wood structures air movement is the killer - it lets water vapor into the wood and if it can’t dry out it rots fast.

There’s all sorts of research into how to reduce air movement while still allowing water vapor to escape.

The big problem with the oft repeated "Let the house breath!" is that if you don't bother to control air leakage you're letting that unfiltered, unconditioned air percolate through the insulation which can be a good media for mold and mildew to grow in. Not to mention the fact that you're throwing away energy, even ignoring air conditioning surely you're still heating during the winter.

Ideally you'd have an airtight house and bring in fresh air through an ERV or HRV to save energy and filter it but even if it's just fresh untreated outside air brought in straight from a vent you'd still eliminate the moist air moving through fiberglass batt insulation and the occasional condensation on the paper backing of the drywall. One thing I really like about spray foam insulation is that your insulation is your air barrier and thermal barrier and you don't have to deal with air passing through your thermal barrier and potentially causing condensation. In southern climates the air barrier is always on the outside of the insulation and in northern climates from what I understand they put the air barrier on the inside. Spray foam effectively puts it on both sides so you're not compromising based on what location is more often going to prevent condensation.

Think about what an air filter looks like after a few months. That's what happens inside wall cavities in leaky homes only there's no way to change them and it builds up slowly over decades. There's a lot more surface area, but that only delays the problem, if you look at any renovation photos when a wall is opened up after a few decades they're typically filled with dust and grime. Even if you just had a 6 inch duct with nothing but some louvres separating inside from outside you've still eliminated most of the potential buildup.

I agree that a tight house is desirable for many reasons, but proper ventilation and indoor air quality are areas of building design and construction that are often severely neglected, even in new construction.

And with the amount of ventilation needed to make a PVC lined box into a healthy living environment, your kids will be conducting airfoil research at the dining room table.