I have terrible problems with neighbour noise flanking through my walls and assumed they must be breezeblock, as I'd read that only those had such issues with flanking. However, having stripped back the plaster layers whilst doing some DIY it doesn't look like breezeblock to me, so I was wondering if anyone could identify what it is?

I've attached a couple of photos. The first is the living room side of the dividing wall between the living room and my bedroom (too much stuff in there to get at the walls that side at the moment) with a section of the two layers of plaster stripped back to show some black/dark-grey stuff underneath.

The second is my hallway wall, where I've dug a hole to remove an old electric cable which was sitting behind a blanking plate (the fuse box was replaced a few years ago and this cable isn't attached to the new one). This gives a better view of the same black/dark-grey stuff that's in the other wall.

 

With no more than there is showing it looks like cinder block to me. What is breeze block and flanking?

is this a condo or duplex? I think the biggest culprit for the noise transfer is the lack of insulation.

 

The OP is in the UK. They have different wording than us!

 

Google shows that breeze block is about the same thing as cinder block but I'm still at a loss as to what is meant by flanking.

 

Well flanking in curtain talk means to lay at the side of the window so maybe it means the noise is right against or laying against the wall.?

 

Seems that breeze block is the UK term for cinder block https://en.wikipedia.org/wiki/Concrete_masonry_unit

I was expecting to see the grey concrete blocks shown on that page but if they're made from cinders then they'd obviously look different.

Flanking noise is just noise that travels indirectly. In my case (I'm in a block of flats), I suspect that neighbour noise getting into the party wall is flanking through the end walls and into the opposite wall (the one shown in the first photo above) as shown by this diagram Flanking sound problems but I guess it's possible that it's also flanking via my concrete ceiling, or via the downstairs ceiling which I presume my walls are resting on, like so Flanking Noise | Green Glue.

If the noise is being carried from the concrete ceiling slabs by the plaster on the walls then in theory just stripping the plaster at the top and bottom so that it's no longer touching the ceilings would fix it. However, if the noise is being carried from wall to wall via the cinder block then I would have to build soundproofed independent stud walls in front of all four walls (and probably strip all the plaster off them first to minimise loss of space) and may still need to soundproof the ceiling if the cinder block is transmitting the noise into that.

If it had been concrete breeze block then I thought I might be able to stop the noise flanking from the party wall into the end walls by stripping the plaster off at the corners and injecting some acoustic foam into the air spaces in the blocks.

 

The best way to stop or reduce noise traveling thru the party wall is to build an insulated stud wall in front of the party wall. I'm not sure what the best cost effective way to stop sound from the ceiling would be.

 

When the blocks are installed..... the holes are up and down so you only see a flat wall. If you could see far enough in the wall you should see the cemented joint.

Filled cinderblocks are a pretty good sound insulator.
They also make an excellent firewall.

If this much attention was used in the wall construction..... it would be doubtful the top of the wall would be "just open."

 

"The best way to stop or reduce noise traveling thru the party wall is to build an insulated stud wall in front of the party wall."

Whilst that's true, because of the flanking problem it will be pointless unless I do the same for all four walls. An analogy I often see is a water leak, where if water is coming out of all four walls plugging the leak in one wall isn't going to stop you getting wet.

The most effective solution for ceilings is supposedly an independent ceiling on joists attached to the walls like this Ceiling Soundproofing Solution 3: Independent Ceiling but I think the walls are the main problem.

 

"When the blocks are installed..... the holes are up and down so you only see a flat wall. If you could see far enough in the wall you should see the cemented joint."

Ah, that explains why I can't see the holes then.

"Filled cinderblocks are a pretty good sound insulator.
They also make an excellent firewall."

I can only assume they're not filled then (I presume you mean they have gaps like the concrete versions that are filled) as whatever I have is certainly not a good sound insulator.

"If this much attention was used in the wall construction..... it would be doubtful the top of the wall would be "just open.""

What do you mean by "this much attention" and "just open"? I don't know if the four walls in the bedroom are all load-bearing (at least one must be as it's an exterior window wall) but I imagine the cinder blocks go all the way to the ceiling and are fixed to it for stability.

 

I disagree, while some noise may be transferred to the adjoining walls, most of it is bound to come from the shared wall. Insulating that wall might not totally eliminate the noise but it should cut down on it considerably.

 

I'm fairly sure (it's obviously hard to be certain) that even if the only noise was coming directly from the other side of the party wall (Flat 7), the noise transferring from there to the other walls would still be sufficient to disturb me, thus for all practical purposes making it a waste of time treating just the one wall.

However the fact that I'm also disturbed by noise from the flat above Flat 7 (Flat 11) and the flats directly below and above me (Flats 14 and 22), which can be heard not just in the bedroom but in the living room side of the dividing wall and in fact sitting 3m away from that wall on the far side of the living room, makes me certain that treating just the party wall would not result in any practical benefit.

 

Maybe you'd be better off focusing your time/money looking for a newer place, one with better insulation/sundproofing between units.

 

Wish I could but unfortunately I'm stuck here for now.