[r-bryan]

Why does a carpenter cut the end off a 10-foot board to get a required 9ft-2in, thereby wasting 8% of the input and incurring dumpster charges? Suppose the architect's design specified the cutlist, to be transmitted to the board "factory", which would cut boards to the required lengths, tagging them with RFID serial numbers indexed to the design, stacking them so the first ones to be used are on the top, and truck to the site without passing through Home Depot?

[bluGill]

The vast majority of the boards and carpenters gets come pre-cut to 92 and 5'8". That is exactly the size you need for an 8' wall. It is only a tiny minority of borders that the carpenter is actually cutting on site. The majority are already pre-cut to the exact size needed.

It would be possible to cut boards to the exact site in a factory. However, you would lose more in the logistics cost of managing all the different possible sizes that you need. Thus two by fours come size multiple of two feet except for the 92 and 5/8's and 104 and 5/8's. Those later too are the extremely common sizes that are used in most commonly.

The truck has to pass through something like Home Depot anyway because all those boards come not on a truck they come on a railroad car and then they'd have to be transferred to trucks to get them to wherever. That Home Depot-like place is also a good place to stage things if you actually are building you'll discover that the dedicated lumber yards are very good at breaking apart all the different pallets of lumber and they figure out exactly what you need and they put those all into one group and bring it to you. Yes, you do sometimes have to cut a 10 foot 2 by 4 and 9 foot 2 inches. However, you are never in the situation where you have a 12 foot 2 by 4, you have to cut to that size because Lumberyard has already figured that out and gotten you the closest to the right size for you. Having been in construction, I can inform you that there are very few boards that actually return to the lumber yard at the end of the build. They are generally right on and getting you the exact amount of lumber you need from the blueprint

[nradov]

All but the cheapest new residential construction has moved to 9'+ walls. Buyers like higher ceilings.

[bluGill]

104 5/8 2x4s also are readily available. Drywall also comes in the correct size to fit 9 foot walls. Home depot stocks it.

[Markoff]

I wonder if someone explained to them difference in heating/cooling expenses + how much the extra 30-50 cm adds also to construction materials

[dlcarrier]

Going from 8 ft to 9 ft ceilings adds 12.5% more volume. For an 1,800 square foot house, in a 30x60 ft form factor, that increases the surface area exposed to outside air by 5.55%. This would create a small increase in the heating and cooling price per square foot, but a similar decrease in the cost per cubic foot.

[bluGill]

You missed something important: many people are moving from a much older house with poor insulation. They can double their surface area and yet see their HVAC bills go down by a lot because modern houses are so much better.

[nradov]

People like to live in nice homes and the cost difference is tiny over the life of the structure.

[Markoff]

construction cost maybe, heating/cool expenses difference won't be so tiny, quite the opposite and it's not only about expenses, lower ceiling is also faster to cool/heat, so you have to wait shorter time

I can really understand high ceiling (in new residential buildings) only for people who use fake built-in second floor (dunno the word in English, maybe mezzanine by my quick research) for like bed or something, but what's the point then and why not build proper separated 2nd floor if you are building new house

[bluGill]

In a modern house insulation is very good (in general) and so your heating cooling expenses are not that high over a lifetime.

[nradov]

I always find in funny when NH users try to claim that consumers like the wrong things.

[bombcar]

You can buy kit houses that basically do what you're describing, up to and including entire log cabins that go together like Lincoln logs of yore (which end up being MORE expensive because they literally build the house at the "factory" and then disassemble it, put it on a truck and reassemble it onsite).

The big problem with kit homes ends up being what happens when (not if) you @#$@ something up.

And the big builders are already bypassing Home Depot, they buy from suppliers that you've never even heard of (the smaller ones buy from suppliers you've heard of, but when you went in everything was 5x the price of Home Depot, because they don't want you as a customer - they want the builders who buy on account and get 80-90% discounts on "list price").

[trollbridge]

Lumber is transported from sawmills via rail cars to some depot where it will then get trucked to places like Home Depot.

There are some large-scale lumberyards that still have a railroad siding and will get lumber by the carload.

A delivery of lumber for a typical house is a full load (or more than one) via truck, and obviously a train isn't going to come to a construction jobsite. So the llumber at the construction site is already hand picked...

It's no big deal at all to cut off ends to make it fit exactly, but when framing most of the 2x4s, etc. are already the exact size you need. You just trim off the top and bottom plates at the edges of the rooms.