My 63 year old father just built his own 3rd home about 7 years ago. He had a single helper, and of course, we all (direct family) helped. Everything was done by him/us, foundation through roof with exception of the gas line hookup hehe. He started as a commercial plumber, welder, steel worker and machinist. Of course, outside of all of us helping to build his 1st, 2nd, and 3rd home, we all (whole extended family and friends) built each other's houses back in Poland in the 80s and early 90s. It's a great feeling watching your whole family working together while you lay bricks as an 8 year old. :-D So, yes, it's not that difficult to build your own house. You'll know the quirks and the issues that will come based on what happens during the build, and you'll be ready for them. However, it is work, so you should be ready to pay all of your friends and family with plenty of vodka and sausage.
How do you know if the building is structurally safe? I’m all for DIY in general, but with respect to a house, my biggest concern would be having the second story of the house collapsing into the cellar :)
And yes, my grandparents in Europe also build their house like you say. Not being involved in the process (nor other family that I know of), I’m afraid that such knowledge isn’t being passed down.
