US houses are notoriously not as well built as in other places in the world. Where I live at the moment for instance is concrete all around, including the roof. I would be surprised if this falling on it would do anything at all and surely wouldn’t penetrate.
Where I live, the common construction for houses is to have reinforced concrete slabs as the floors and ceilings, with the walls being brick except for the load-bearing reinforced concrete columns. The ceramic tiled roof (when there's one) goes above the reinforced concrete ceiling. More than once, I've read about accidents in which Brazilians fell (sometimes to their death) through the ceiling of a USA home, and that's because we simply don't expect the ceiling to be so fragile; our intuition is that the ceiling is as strong as the floor, and that we can walk normally over it.
To those from countries with a similar building culture, USA houses feel really fragile; for instance, what do you mean you can punch a hole in a room's internal wall? We expect these walls to be made of brick.
I have no idea how fast it was going when it hit, but as it is more than 10x the mass of a 50 cal, I wouldn't rely on the assumption that protection from the latter is also protection from the former.
Sure, but that concrete would break up in case of earthquake and kill a lot of people with debris. US houses are much safer in case of earthquake which is much more likely than space debris.
There are places in the US that that type of build is the norm.
Beyond that, “better built” in what sense? I’ve lived in the places that are built like bunkers (literally; Guam builds for direct typhoon hits). They are fine, but aren’t built for earthquakes, energy efficiency, or any other metric that’s more relevant in other parts of the world.
