[jtriangle]

It's a flawed solution based on a misunderstanding of how houses are actually built/designed/engineered. Most of what you see being built today is dimensioned based on available timber. It's part of why all the houses look the same, because it's the most efficient way to build. Everything structural gets built with 2x4's or prefab trusses (which are also made of 2x4's), windows are all standard sizes, as are cabinets and flooring, and siding, and trim, and if you weren't terribly concerned with building homes that were interesting to look at, you could probably optimize all of this further on the design side of things and then prefab things like walls and door frames then lego them together and wind up with something much nicer and likely cheaper than what they're doing.

The premise isn't terribly flawed though, prefab everything into 4x8ft panels, standardize your roof trussing, standardize your layout, and you can probably dig up a little more margin for builders to put directly in their pockets, and have perfectly cookie cutter houses with no regard to the environment they're placed in. Not really a neighborhood I'd like to live in, but, also not too dissimilar from what most of america lives in, so, I suppose it's tolerable.

[kyawzazaw]

That's not how we build in my country though

[omnimus]

Yeah most countries in the world dont have 2x4s

[alkonaut]

We do in some sense but we call it something else like 45x120 or similar. That's not 2x4" but nor is a 2x4 actually 2 inches by 4 inches generally.

But what we definitely don't do is stick build homes using 2x4s apart from interior walls. An exterior wall where I live would probably use 45x220mm studs and probably more wood as well for a total depth of 350+ mm.

[aredox]

We don't use that wood to build houses. The US is special in that respect.

[jtriangle]

Realize we have a very, very large country, and it's chock full of forest, so plenty of lumber resources to do such things. Other places use different materials/techniques/etc which are mostly based on what resources they have easy (read: cheap) access to.

Also not all of the US uses timber framing, for instance, in costal florida, it's not uncommon to have concrete walls that are framed with sheerwall inside, so they can survive a hurricane.

[manfre]

2x6 is becoming more common for framing walls. The extra depth allows for more insulation.

[jtriangle]

To be fair, we don't technically have 2x4's either, they're a fair bit smaller in reality...

[PaulDavisThe1st]

> Everything structural gets built with 2x4's or prefab trusses (which are also made of 2x4's)

Neither of these statements are true. 2x6's are commonly used for a variety of reasons in vertical placement. 2x8/2x10 and even 2x12 are still common for floor joists where manufactured beams (e.g. I-beams) are not used. Trusses are not always built with 2x4s either.

I'd also mention (as a recently certified firefighter) that the use of trusses in modern construction causes real headaches for the fire service: a minor failure in one part of one truss can lead the entire roof surface to become a collapse hazard. They are efficient uses of lumber but have few other merits as a construction technique.

[elihu]

If one wants to go the "lego things together" route, ICF and AAC are also options that exist already.

[orthoxerox]

AAC is great, but

- I don't think it's super common in the US - it's a high-tech product that quickly loses its legolike value if quality controls get sloppy (you have to spend hours sanding down each row or switch to mortar) - it's just walls, you still need a system for building foundations, floors, ceilings and roofs.

[elihu]

I think AAC is pretty rare where I am (Oregon) but apparently there's a company in Bend that specializes in it. They're a Hebel distributor.

https://northwestaac.com/

AAC floor and roof panels do exist.

My impression is that ICF is a lot more common in my area than AAC, though it's still not super common compared to, say, stick frame construction. I'd guess that's probably because with AAC you'd need to add additional insulation, whereas with ICF you wouldn't -- but maybe there are other reasons.

[orthoxerox]

AAC doesn't always require additional insulation. The rule of thumb is that a wall X mm thick made of AAC with density X kg/m3 has a metric R-value > 3, which is sufficient for Central Russian climate (which I am told is similar to Vermont, colder than the PNW). I have no idea what kind of blocks are sold in the US and how to convert between metric and imperial R-values, but online calculators suggest that a 300mm thick D300 block should have an imperial R-value of about 18.

Northwest AAC claims even higher values: "[f]or example, the R-value of a typical <...> 12-inch wall is R-29", so either I'm converting the wrong values or the measurement standards are very different across the countries. Xella (Hebel) claims their blocks are warmer than standard blocks, but 50% more sounds like too much.

[lucideer]

> based on a misunderstanding of how houses are actually built/designed/engineered. Most of what you see being built today is dimensioned based on available timber. It's part of why all the houses look the same

It's worth pointing out that this is a UK-based project (where typical houses are concrete construction). A lot of the comments dismissing it are suggesting it should conform to American standards on the assumptions that those standards are universal.

As an open-source initiative it should certainly have a broader perspective than being purely UK-centric, but replacing that with a US-centric one isn't the solution.