Do you live in a cardboard box ffs?
Purpose built block of 36 flats. Hopefully building standards have improved since the mid 80s, but decent soundproofing is very expensive, and flats are built for investors these days, not the people who have to live in them, so I'm not confident. Basically it's safe to assume that If you live in a flat you live
with your neighbours in the same way you live with your family in a normal house. It's just less acceptable to yell at them.
In France & Germany a lot more people live in flats, but the culture is quite different to ours in most areas. There is an unwritten code of conduct which means just about everyone appreciates the fact that you have to be considerate. Here the attitude (displayed in many similar threads over the years) often seems to be very much along the lines of "it's my flat and I'll do what I want with it." And it doesn't take many people like that to cause widespread problems.
Perhaps that's why the UK has such awful stats when it comes to complaints about noise. Of course it's not all down to people living in flats, because a terraced property can be no better, and having a semi or even detached place doesn't protect you from antisocial neighbours.
It's not a bad start though. Ten feet of solid granite would probably be best unless your neighbour's hobby is juggling nitroglycerin.
Andrew McP
PS FWIW in the 10+ years I've been here and partially involved in managing the block,
all the complaints we've had about noise have come from the minority of flats which are rented out. That's not a slur against all, or even most renters, because many -- like the OP here -- are very considerate. But there is a "knack" to sharing a home or living in a flat which many people take time to learn. And some never do.
Personally I've never wanted a big house (big house, big running costs), but I would like a very small one in the middle of a large field.