mid terrace soundproof/rendering

[stndiy]

We recently bought a 1940's mid terrace house and have discovered since moving in that we can smell what the house on one side is cooking and we can hear them talking and sneezing,etc.
I need advice on what could be the problem, I know we share chimneys with them but the noise seems to be coming through the wall area not the fireplace.
The walls are brick with plaster over it and no plasterboards, I am wandering whether there is a serious problem with the walls as we shouldn't be hearing them as much as we do - they are not loud people.
Can anyone advise me on what the best option is regarding soundproofing or getting the walls checked? we don't want to start putting up stud walls as we can't afford to lose the space. Any advise would be great

 

[Deluks]

Might be voids under the floorboards, where the joists are built into the brickwork? Worth checking.

Other than that not much you can do without increasing the mass of the wall which will definitely mean losing space, the least you'll get away with is about 4".

 

[cmother1]

The cooking smells sound a bit sinister. This suggests an air connection between the 2 properties. Do the neighbours have something like an extractor hood vented into a dis-used shared flue. I had this problem in the last house I lived in. Not easy to fix if there's a gap in the flue between the 2 properties.

 

[joe-90]

I was in a terrace house yesterday and you could clearly hear noise from next door. I guess it's just a 4inch thick wall. Not much you can do once the vibrations are in the fabric of the property.