I work in the construction industry, you did not ask the LLM the right questions.
1) is already the way residential construction works. Conduit isn’t used in homes aside from Chicago and a handful of other jurisdictions but all conduit can be cut with a sub $500 tool called a portaband. Plumbing pipe can be cut with a portaband. There are multiple power tools that can be used to cut sheet metal. Fittings for the electrical, plumbing, and HVAC trades are commoditized and standardized.
2) Drywall and drywall finishing is the cheapest labor on a building site aside from the cleaners and maybe the insulators. The framers, finish carpenters, equipment operators, flooring workers, and MEP trades all make more than the drywallers, mudders/tapers, and painters.
3) Raised seam metal roofs are great and last longer than asphalt shingles, but it’s more expensive up front.
4) Solar roofs have far too many terminations/connections to be reliable, the upfront cost may possibly never be paid back. That could change, but it’s a tricky problem.
> That leaves the foundation + architecture / engineering work as the hard part. Most of the design work for that stuff could be automated. Let the homeowner and builder boss an LLM around, and then run the LLM output through code compliance + simulation gates. The latter is really important because most local code is hazard or climate dependent, and having good deterministic vetting of designs would let the construction process apply to multiple climates.
The architect and engineer design the construction documents to adhere to the codes in the jurisdiction the structure is being built in, no LLM needed. Most jurisdictions just adopt one of the standardized codes for general code like the IBC and then various trade codes like the NEC.
Things like roof load calculations for areas with snow make designing a house that works in both California and Minnesota not worth it unless you want to overengineer your roof for California.
There’s an entire massive industry focused on shaving costs to increase margins that have been working on these problems for a long time.