Spent five minutes googling (so now I'm an expert! /s). So much spam on this topic. The most reasonable answer I found so far kindof matches up with your answer

Spent five minutes googling (so now I'm an expert! /s). So much spam on this topic. The most reasonable answer I found so far kindof matches up with your answer: https://www.quora.com/How-hard-would-it-be-to-build-tornado-proof-homes-or-even-fortify-existing-homes-against-tornadoes/answer/Steven-Barnes-151 https://www.quora.com/How-hard-would-it-be-to-build-tornado-... So first off, to survive the wind speeds of an F-5 tornado wouldn’t be hard to build. This issue is more about price than difficulty. Add extra fasteners, sturdier materials, etc. Once you get the foundation properly anchored and the frame reinforced, the rest is very simple. The real issue is with the debris. Imagine a tree being tossed into the house. Even IF you built the walls to withstand it, which would be insane in a residential structure, you still have doors, windows, etc. Unless you build underground, or spent 5x more for a tiny house, it would be near impossible. Your best bet is to not build in the middle of a tornado-prone area.