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Isocheck Underwood

Impact & airborne improvement system for laminate and wood flooring

The Isocheck Underwood system is designed to be used under laminate and wood flooring. It is designed to provide resilience, durability and support to protect the floor covering against undue stress.

Isocheck Underwood is a lightweight, 3.5mm thick layer of recycled rubber crumb (mainly vehicle tyres) bound together in a unique latex formulation. This high content of recycled raw materials ensures that the product has strong environmental credentials.

Isocheck Underwood's integrated metalised scrim ensures good resistance to moisture transmission thereby eliminating the need for an additional polythene sheet.

  • Thickness: 3.5mm minimal build-up for height-restricted applications
  • Environmental: Made from recycled rubber crumb, mainly vehicle tyres
  • Moisture Protection: Integrated metalised scrim eliminates need for additional polythene sheet
  • Performance: Achieves up to 26dB ΔLw in laboratory conditions
  • Versatile: Suitable for use with underfloor heating systems
  • Applications: Ideal for refurbishments, conversions, and listed buildings requiring minimal structural change

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To be used over floorboards or concrete floors for conversions, refurbishments or listed buildings requiring minimal structural change.

Isocheck Underwood is particularly suitable for projects where minimal height build-up is critical and where environmental credentials are important. The system works effectively with both timber and concrete substrates.

For advice on treatment of services and penetrations, consult our brochure or visit our website. 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.

Isocheck Underwood will typically achieve up to 26dB ΔLw in laboratory conditions.

The system provides effective impact and airborne sound reduction while maintaining minimal build-up height, making it ideal for refurbishment projects with height restrictions.

Overall size: 1000mm x 10m roll
Resilient layer: 3.5mm recycled rubber crumb
Weight: 12.6kgs per roll (1.2kg/m²)
Composition: Recycled rubber crumb (mainly vehicle tyres) bound in latex formulation
Moisture protection: Integrated metalised scrim

The acoustic floor shall be Isocheck Underwood, supplied by Isomass Ltd. Unit 14 Papworth Business Park, Stirling Way, Papworth Everard, Cambridgeshire CB23 3GY and installed in accordance with manufacturer's instructions / recommendations.

  • Lay Isocheck Underwood over the entire level floor with all joints butted
  • Most t&g or interlocking laminate panel floor finishes can be laid directly onto Isocheck Underwood. If in doubt please contact us with the floor specification
  • Finished timber floors should be isolated from the skirting using Isocheck Acoustic Flanking Band
  • Isocheck Underwood is also suitable for use in underfloor heating systems

Full installation instructions are available and must be used in conjunction when laying this floor system.

Timber floor construction:

  • Laminate or wood flooring
  • Isocheck Underwood
  • Floorboards over 200mm x 70mm timber joists @ 450mm centres
  • 100mm 45kg/m³ insulation between joists
  • 25mm o/a double boarded ceiling (min. 20kg/m²) fixed to timber joists
  • Acoustic flanking band reduces impact vibration leaking via structural walls

Concrete floor construction:

  • Laminate or wood flooring
  • Isocheck Underwood
  • ≥300kg/m² hollow core concrete with 80kg/m² sand/cement screed or 40mm screed
  • Min. 75mm void formed by metal frame suspended ceiling system with ≥10kg/m² gypsum board ceiling

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