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*Please Note: PhoneStar was previously branded as Phonewell

It is an easy task to soundproof timber floors with PhoneStar acoustic insulation and it gives very good results at reducing both airborne sound and impact sound through timber floors, while losing very little room height. This system is very popular for reducing noise coming up from the flat or apartment below as well as reducing noise within one’s own home. This option requires access to the floor above and to the joist cavity. For other options please see Soundproofing Floors.

Soundproofing Timber Joist Floors



Should meet Building Regulations for the Passage of Sound for Change of Use, Remedial and Refurbishment projects. Choose where there is only access to the floor above and no access to the ceiling below e.g. in apartment dwellings.


  • Top-deck or finished floor surface
  • 15mm PhoneStar Acoustic Insulation
  • 18mm chipboard / OSB / floorboards
  • 235mm solid timber joists
  • 100mm deep x 45kg/m³ mineral wool
  • 15mm Sound Resistant Plasterboard, second layer for fire regulations may be required

Materials List: (available from our stockists)

  • PhoneStar Acoustic Insulation on Floor (1200mm x 800mm x 15mm)
  • PhoneStar Eco-tape (50mm x 50M)
  • 18mm chipboard / OSB / existing floorboards (seal if necessary)
  • 100mm x 45kg/m³ density mineral wool between joists
  • Flexible mastic or Acoustic sealant

Please download the full installation instructions for soundproofing timber floors before commencing work:

Brief Instructions: (have you considered Flanking Noise?)

1. Fill the void between the joists with 100mm min. x 45kg/m³ density mineral wool, by accessing the void from above.

2. Re-fit the 18mm sub-deck or lay a new floor if appropriate.

3. Examine the timber sub-deck and fill any holes or gaps with flexible mastic or acoustic sealant – tradesmen will often tack down 3mm hardboard sheets to level and seal. Also seal around the perimeter walls.

4. Ensure the floor surface is clean and even.

5. Begin in one corner and lay the PhoneStar boards on the sub-deck, butted tightly up to the perimeter walls. Do not screw or nail the boards down.

6. Butt each PhoneStar board up tightly to each other and do not leave any gaps between or around the PhoneStar layer. Lay in a brickwork formation if possible. See Cutting and Taping PhoneStar.

7. Install the finished floor surface as per Fitting Floor Coverings over PhoneStar.

8. Fit skirting boards ensuring no contact with the floor – leave a 2mm gap.

9. Consider treating any identified flanking walls with PhoneStar.