Underlay Recommendations

DJM_4

We are looking to recarpet the communal area of a three storey block of converted flats (stairwell and halls), five flats in all.

Stuck on the pro's and con's of which underlay to choose between these two - Waffle rubber (100lb weight) or PU (Cloud 9 Cirrus - 9mm).

Sound reduction qualities probably more important than thermal qualities. To be laid on wooden, late Victorian/early Edwardian staircase.

Be grateful for your opinions or thoughts. Thanks.

Edit:

Ps. I am not a rich sod who owns all these flats, I just own one of them (well me and the bank). Just in case you were thinking "Get lost you rich sod, I'm not helping you", or words to that effect.

Heath_Robinson

The 11mm Cloud 9 Cumulus (damn silly names for underlay don't you think??) is well thought of in AV circles for it's sound deadening.

http://www.completelyflooring.co.uk/product_info.php/cPath/99_91/products_id/848
£2.65 a meter there. Not used them before though.
Impact Sound Rating: 43db

Compared to 32dB with the 100lb stuff and 39db with the cirrus.