Isocheck 28T, 24T & 15T

Acoustic floor systems: direct to timber floors
Isocheck 28T, 24T & 15T are high performance acoustic floor systems designed to reduce impact sound transmission through traditional timber floors where no additional precautions are required for higher domestic loads in bathrooms and kitchens.


Isocheck 28T and 24T consist of a 6mm layer of Isofiba bonded to 22mm or 18mm P5 V313 moisture resistant chipboard, whereas Isocheck 15T consists of a 6mm layer of Isofiba bonded to 9mm moisture resistant medium density fibreboard.


When installed as part of an Isomass approved separating floor construction either system enables a traditional timber joisted floor to meet the sound transmission standards of Approved Document E 2003 and subsequent amendments in 2004, 2010, 2013 and 2015.

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To be used over existing floorboards for conversions, refurbishments or new build with a decoupled ceiling as illustrated or approved by Isomass (on application to for our free acoustic detail design service ). Isocheck 15T has also been tested for use over water-fed underfloor heating systems.


Treated floor with:
R,w+ Ctr
DnT,w+ Ctr
Isocheck 28T
Isocheck 24T
Isocheck 15T

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

Overall size: Isocheck 28T
Isocheck 24T
Isocheck 15T
2400mm x 600mm x 28mm
2400mm x 600mm x 24mm
1200mm x 600mm x 15mm
Resilient layer thickness: 6mm
Resilient layer: Recycled Isofiba
Weight: Isocheck 28T
Isocheck 24T
Isocheck 15T
23.0kg per sheet
19.0kg per sheet
5.2kg per sheet

Isocheck 15T has been independently heat-flow tested and showed the following ratings:

Thermal conductivity: 0.069W/mK
Thermal resistance: 0.203m2K/W


Isocheck 28T, 24T or 15T 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 28T, 24T and 15T are available as a pdf to download. Go to the Downloads tab on this page.

  • Isocheck 28T, 24T or 15T acoustic flooring.
  • floorboards.
  • 200mm x 70mm timber joists @ 450mm centres.
  • 100mm 45Kg/m3 insulation between joists.
  • 20kg/m2 double boarded 25mm o/a plasterboard on resilient bars @ 400mm centres perpendicular to joist direction.
Isocheck 28T and 24T application section - perimeter
Isocheck 24T Application visual

Isocheck 28T, 24T & 15T Installation instructions

Isocheck 28T, 24T & 15T product data sheet

Get in touch

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