Best Soundproof Products Tredaire Colours Red 11.4mm Carpet Underlay £73.97 – £1,479.73 Select options Carpenter Ultimate Living 10mm Carpet Underlay £5.87 – £586.44 Select options Hard Wearing Carpenter Rich Step 9mm Carpet Underlay £4.77 – £477.37 Select options No.1 Sound Reducing Carpenter Deep Step 11mm Carpet Underlay £5.58 – £556.80 Select options