Under Floor Insulation

Suspended Timber Ground Floors

Knauf Insulation Suspended Ground Floor Insulation Glass Mineral Wool


In a suspended timber ground floor, insulation is placed between the joists and supported on netting (e.g. polypropylene) or timber battens.

In this application, an important consideration is the thermal and acoustic performance of the insulation.

Our Mineral Wool insulation solutions for suspended timber ground floors ensure that the product used fills all gaps between joists to prevent air movement which can lead to unwanted heat loss.



Installed from below


Installed from above

While Knauf Insulation offer various insulation products into suspended ground floor applications, we would emphasise that site specific conditions should always be considered on a case-by-case basis and any generic product recommendations must always be subject to an onsite evaluation.



  • Mineral Wool provides the best combination of thermal, fire safety and acoustic performance.
  • Mineral Wool is easier to install correctly than other insulants such as rigid boards because it adapts to any slight imperfections in the substrate and knits together, eliminating any air gaps. Evidence shows the absence of air gaps is crucial to achieving real performance in the relevant application.

Download our Solutions Guide Download U-value Tables

Use our online condensation risk analysis tool for an assessment before you start work on your under floor insulation.

Try our Online Condensation Risk Analysis Tool

Technical Support Team

For any U-value calculations for alternative construction build-ups, please contact our Technical Support Team on 01744 766666.

For written U-value calculations, please complete our contact form by clicking here, including details of your full through construction build-up and we will respond accordingly to meet your requirements.