I’m certainly no Bob Villa. I’ll even admit to sitting at a desk in my day job. But if you do a bit of reading on home construction topics, you realize that there is a central theme to it called “common sense”. Gravity is trying to pull everything down, heat travels from warm areas to cold areas, electricity will follow the path of least resistance, etc.
Unfortunately, Horace Greeley was right: “Common sense is uncommon.” Old homes are often great demonstration grounds for this sort of thing. Decades of hacked solutions to immediate problems layer onto neglect and complacency .. perhaps some pictures sum it up best: