Isocheck ULTIMO

Acoustic floor system: for timber or concrete floors
The Isocheck ULTIMO system is designed to reduce sound transmission through traditional joisted timber floors, where access to ceilings may be limited.


Isocheck ULTIMO consists of 5 – 6mm Isofiba resilient layer bonded to 10mm fibre reinforced gypsum board, with a bonded top layer of 9mm thick t&g moisture-resitant board.


When installed as part of a complete sound reduction system, it enables a timber floor to meet the sound transmission regulations of Approved Document E 2003 and subsequent amendments in 2004, 2010, 2013 and 2015.

View more technical information and downloads

To be used directly over existing floorboards in conversions, new build and listed building projects. Suitable for projects which include directly-fixed or low-mass ceilings, for example, flats over commercial properties or timber frame flats. Could be installed as illustrated or approved by Isomass (on application to for our free acoustic detail design service ).


Treated floor with:

Isocheck ULTIMO on 18mm floorboards

R,w+ Ctr
DnT,w+ Ctr

Site results (in red) for Building Control approval.
Laboratory results (in blue) for comparison.

Overall size: 1200mm x 600mm x 24mm
Resilient layer thickness: 5 – 6mm
Resilient layer material: Isofiba
Weight: 18.6kg/m2  (13.4kg per sheet)

Isocheck ULTIMO acoustic flooring, supplied by Isomass Ltd. Units 10 & 11, Avenue Business Park, Elsworth, Cambridgeshire CB23 4EY and installed in accordance with manufacturer’s instructions / recommendations.

Full installation instructions for Isocheck ULTIMO are available as a pdf to download. Go to the Downloads tab on this page.

  • Isocheck ULTIMO acoustic flooring.
  • floorboards.
  • 200mm x 70mm timber joists @ 450mm centres.
  • 100mm 45g/m3 insulation between joists.
  • 25mm o/a double boarded ceiling or Lath & Plaster ceiling (min 20kg/m2) fixed to timber joists.
  • acoustic flanking band reduces impact vibration leaking via structural walls and assists in reducing airborne sound paths.
Isocheck ULTIMO acoustic floor system
Isocheck ULTIMO acoustic floor system

Isocheck ULTIMO Installation instructions

Isocheck ULTIMO product data sheet

Get in touch

Call us on 0845 838 33 99 or get in touch for more information