In my former BCO patch of New Malden, SW London, we did find
a late Victorian cottage with cavity walls and flat iron ties,
but most spec builders will still using 9" external walls
throughout the 1930's. Party walls though were almost invariably
9". In my BCO days (1976-84) party walls were sometimes solid,
sometimes cavity: both complied.

Also, is a modern party wall much more sound proofing that the 9"
brick ?

Workmanship has far more to do with it, also whether or not the
wall is wet plastered.


I am sure a cavity party wall would cut down a lot of the impact noise
on solid party walls - kitchen cabinets, fitted wardrobes, even joist
movement noise. Also, noise from a TV next to the wall is transmitted
by resonance of the wall at some frequencies - like high-bass booming.

If so, this could be a factor in future home purchases.
Unfortunately you cannot tell how well the wall has actually been
built. Some of the 30s walls are very dodgy when you remove the
plaster, since they were never intented to be seen.

I've told the story about the house built of 1/2 bricks. For a party wall
the vital thing is that the mortar joints are properly filled so that
there are no air leakage paths.


This could be improved if both neighbours were doing a complete
renovation.
Also, the hardness of the bricks will make a lot of difference. But I
suppose
it is a balance of sound absoption and mass. I very hard brick wall
could
actually propogate more sound, despite being heavier.
I wonder if some kind of injectable fluid could be invented that would
make a brick wall more sound isolating ... and there goes the patent
possibilities !

Check out the ODPM website for the current regs (tightened up because
of perceived failings in this area)

http://www.odpm.gov.uk/stellent/grou...ge/br0046.hcsp

One thing I heard - not from reading the regs myself, is that internal
walls between e.g.
bedrooms will have to have good isolation. This makes a joke of the
cardboard partition
walls in a lot of new houses upstairs. Will builders have to go back
to much
more solid internal walls ? This was one good thing about a lot of the
older houses.

Simon.