Thank you for your enquiry. The easiest and quickest way for improvement with access to the flat above would be to install a layer of our SBM5 to seal the gaps in the existing floor then install our Quietfloor plus insulation. This product is used instead of underlay and carpet is installed directly onto it. I have attached a link to our page on our website for your perusal.

http://www.soundservice.co.uk/quietfl...