Got one of those odd problems that occurs when you live in a house that's been altered a bit in it's 100+ years. I live in a victorian semi detached house and the two houses were built by two brothers (bare with me, it's relevent). At the back of the house was originally one big room that ran the width of both houses with no wall in between. There was a sash window about half way along this room. About thirty years ago this room was seperated by adding a concrete block wall and that's how it was when we moved in. The block wall runs in at 90 degrees to the window and arrives right in the centre of the window (which has never opened). There is a bit of polystyrene insulation stuffed in between the end of the block wall and the window glass which stops one house being able to see round to the other. Obviously this isn't ideal from the point of view of stopping fire getting from one house to the other.

We are modernising that part of the house and would like to sort this out. We will be removing the big sash window and replacing with two smaller windows (one each side like in a normal house). I guess I could extend the block wall (with stone rather than concrete block) so that it reaches the outer surface of the house and then windows in either side. Then fire can't get round and it would be like a 'normal house'. I don't mind doing that but wondered if there are any other solutions that would still provide adequate firestopping between the two houses maybe just with timber or metal windows side-by-side.

Many thanks for any help.

Jules

Many thanks for this. Yes - you're quite right about the sound. We have an attic room with brick party wall and I hadn't spent much time up there previously. Went up there a few months ago and someone was playing the guitar (badly) just the other side of the wall. It was like they were sitting right next to you (which they basically were). Have now got soundproof board on it and it's made a huge difference.

Will do the last little bit in block and then it'll need a new stone mullion on the end of the wall which will split the current sash window in two and create a proper masonry division between the two houses.

Will be tackling the attic after this. Probably got the same problem but much trickier to access the outside of the window. Thanks again!

https://www.noisestopsystems.co.uk/shop/wall-soundproofing/noisestop-2-panel/

Incredibly heavy for the size but seem effective.