I totally forgot about this but I used to live in a flat in a terraced house; that dated from c.1910, there were massive gaps in the floorboards as it seemed they had been built from reclaimed wood or something, so much so that in places you could see right through to the downstairs flat if you put an eye to the floor. The sound insulation between my flat and the downstairs flat was non-existent and also between the property my flat was in and next door; though no-one lived in either next door most of the time as the owners just came back now and again to do a bit of work on the houses in order to sell them on. I also lived in a very tiny 2up, 2 down ( was told they used to be 1 up, 1 down) and that also had poor sound insulation problems, the couple next door would have blazing rows and we'd hear every word and also every word and note of the 80s Eric Clapton song they would play on a constant loop when the other walked out of the house. I think that terraced houses that were more 'slummy' in the past as opposed to being built for the middle classes tend to be less solidly built. xx