Lumber is cheap because there's lots of land where we now farm fast growing trees.
Wood frame houses are cheap today because of the invention of the stamped metal framing connector, which has enabled large elements to be made off site in high volume. It's also why houses typically don't have attics anymore.
That's really strange to me, every house I've ever lived in (5 houses since 1991 , all in the southeast, all new construction) has had an attic and I can't even imagine what a house without an attic would look like. (I guess a flat roof, but only weird modern houses and apartments have flat roofs and there are not many modern houses)
In a lot of contemporary construction it is an uninhabitable space between the eaves and roof. An analog to a crawl space.
In contemporary construction, habitable attics usually get listed as bonus rooms.
The GP is thinking of something reached by stairs. Nonhabitable attics usually are accessed by ladders or ladder like objects.
(Edit: to be clear this is for residential construction which tend to be small 1-2 story buildings.)
There are things called attic trusses:
* https://design.medeek.com/resources/truss/trussgallery.html
You can also use (vaulted) parallel cord truss:
* https://www.dimensions.com/element/truss-vaulted-parallel-ch...
See also various other configurations:
* https://www.menards.com/main/buying-guides/building-material...
https://www.youtube.com/watch?v=3oIeLGkSCMA
Ninja'ed
I would guess the decline in livable attics in new construction is mostly attributable to changing consumer preference.
Yes, it is. It doesn't have to be usable to be an attic. It just needs to be a space between the ceiling and roof.
Unless you use attic trusses:
* https://design.medeek.com/resources/truss/trussgallery.html
Or (vaulted) parallel cord truss:
* https://www.dimensions.com/element/truss-vaulted-parallel-ch...
As someone who framed houses as a job and designed and built three of my own I disagree with your take on attics.
It is common for houses not to have an attic because builders must build cheap to compete. Attic space can be cheap square footage, but it has to be part of the plan from the beginning and is difficult to make it an option to pick.
You can indeed have an attic with "attic trusses". They are still built out of dimensional lumber and stamped connectors - the bottom chord will be much larger. I've seen them span 36', not sure what the limit is.
On one house, to do a partial attic was only $2000 extra for the trusses. Attics present other problems/expenses too, like additional stairs. (Many plans didn't have a place where extra stairs can be added as an option AND work with the truss layout.
HVAC is another issue. You either end up with a second system for the attic or need to have space in the floor below to run ducts to the attic space. Again, most of your cookie cutter plans didn't leave a space for this. When walking my HVAC guy through my house to plan ducts he asked how much of this closet he could have for ducts. I told him "as much as you need to make it work correctly". From the look on his face you'd think he won the lottery. He replied "no one ever says that!".
Attic spaces require different insulation techniques, they aren't difficult, but cookie cutters don't like different.
I've used attic trusses on 2 of 3 houses. The one where I didn't was because stairs, HVAC and I didn't need more space (full extra height basement, daylight windows - that was enough).
https://www.nytimes.com/2024/06/08/headway/how-an-american-d...
"What may ultimately force the adoption of industrialized housing in the United States is a skilled labor shortage. This has already affected one area of home-building: roof trusses, the structural timber frameworks that support a roof. Trusses require precisely cutting angles, a skill few workers possess, and so the structures are now mostly made in factories."
Lumber is not timber. Lumber can be moved about by a single pair of hands and fastened with nails...American construction takes advantage of the industrial revolution and uses commodity nails.
Worth noting that where Americans use concrete and brick, they also use steel reinforcing so that their buildings don't collapse brittle collapse from earthquakes and wind.