In article , Ian_m wrote:
An old cottage I once worked on had egg boxes filled with crushed
cockle shells between the floors to deaden sound, it worked well.

The Hampton Court fire revealed that Sir Christopher Wren had used
crushed shells for this purpose 300+ years ago. I stand to be corrected
but would guess that shells have a fairly porous surface which probably
does a much better job of soaking up sound than mineral wool does.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm
[Latest version QSEDBUK 1.10 released 4 April 2005]