Isocheck ULTIMO System : overlay platform system direct to floorboards

Isocheck PRIMO & PRIMO HL Isocheck ULTIMO Isocheck 32T Isocheck 37T Isocheck 27C, 23C & 14C Isocheck 28T, 24T & 15T Isocheck RENOVO Isocheck Deep Batten Isocheck Shallow Batten Isocheck Cradle Isocheck Barrier Mat 5 & 10 Isocheck Impact Mat 100, 200 & 300 Isocheck Re-Mat 3 & Re-Mat 5 Isocheck Re-Mat Base 3 & 6 Isocheck Re-Cork 3 & Re-Cork 5 Isocheck Screedcheck XL5 Isocheck Screedcheck XL8 Isocheck Screedcheck XL10 Isocheck Phonewell Isocheck Absorba ceiling & wall panels Isowave System 23 for Walls Isowave System 23 for Ceilings Accessories

product data sheet
installation instructions

NHBC Tested

0845 838 3399


•  Refurbishments
•  Conversions
•  Listed Buildings requiring minimal structural change

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 and 2013.


To be used directly over existing floorboards in new build, conversion 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.

Typical performance expectations (on the construction illustrated)

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.

Product data

Overall size: 1200mm x 600mm x 24mm
Resilient layer thickness: 5 - 6mm
Resilient layer material: Isofiba
Weight: 21.8kg/m2


The acoustic treatment shall be:

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


Lay Isocheck ULTIMO over a structural timber sub-floor, in brick bond pattern, applying Isocheck adhesive to all tongued and grooved panel joints.

Apply Isocheck Acoustic Angled Flanking Band on the edges of the Isocheck boards just before they are pushed against the perimeter walls to isolate the board from the wall.

Install skirting and trim off excess Flanking Band.

Full installation instructions for Isocheck ULTIMO are available to download by clicking on the link to the left of this page. Installation instructions must be used in conjunction with this information and/our information contained in the datasheet when laying the Isocheck ULTIMO floor system.

Please ask Isomass for guidance when considering the weight of any new blocks which will be incorporated in a wall directly surrounding a timber separating floor.


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Isocheck ULTIMO


  • Isocheck ULTIMO.
  • floorboards.
  • 200mm x 70mm timber joists @ 450mm centres.
  • 100mm 45g/m3 insulation between joists
    (total ceiling mass 20kg/m2)
  • 25mm o/a double boarded ceiling or Lath & Plaster ceiling
    (min 20kg/m2) fixed to timber joists.





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