Our neighbours (3-bed 1930s semi) can somehow generate severe vibrations in our property that travel across the party wall, up from the floor into bigger items (e.g. the sofa, bed, etc) and make you jump/move uncontrollably. I know it sounds crazy but it happens numerous times daily as they enjoy terrorising us (waking us up, etc). It seems they get some kind of indication where we are in our property so they can always target us successfully.
The noise is everything from conversations to foot steps to sockets to crockery in cupboards to doors closing (these can be like explosions). It started after their water tank burst and flooded down the party wall for days as they were on holiday.
Prior to this the soundproofing was nearly 100%. Very rarely heard a thing and felt nothing. It developed into vibrations after their building work (2 years after flood) but those vibrations were in response to heavy footsteps or door slams next door - nothing like it is now.
I have talked to surveyors, noise consultants, builders - nobody has been able to help. I know nothing about building, DIY etc but from years of research, etc it sounds like we have shared joists and maybe these have become loose or something (at the party wall - flood? building work?) so weight on our side cause them to rise (e.g. floorboards slightly?) in the neighbouring property (see-saw type effect?) ? Then they stand/jump on this making them knock our floorboards causing these vibrations? No idea if this is even possible but desperate to find out what is happening in order to stop it!!
So - sorry for the long post - if anyone has any ideas, come across this kind of thing before or could recommend what kind of expert we need to investigate (e.g. structural engineer?) it would be very much appreciated.
There seems to be some similarities with this post :
(...joists span both hallways ... impact noise transmits straight across the shared joists into my house ... whole of my hall floor creaks really loudly when they walk about...)