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*Please Note: PhoneStar was previously branded as Phonewell

Soundproofing timber floors with PhoneStar acoustic insulation is a relatively easy task and gives excellent results at reducing both airborne sound and impact sound through timber floors. This system will surpass building regulations for sound and it will only reduce room height by 15mm. This is the Ideal Solution for Soundproofing a Timber Joist Floor, and it requires access to the floor above as well as to the ceiling below. If access to the ceiling below is not available see our other options in Soundproofing Floors.

Ideal Soundproofing Solution



Will meet and exceed Building Regulations for the Passage of Sound for New Build, Change of Use, Remedial and Refurbishment projects. This is a simple, slim solution which offers ultimate performance.
Sound Test Results: Airborne 60dB(-6) Rw (–Ctr) & Impact 53dB Ln,w


  • Finished floor surface or top-deck
  • 15mm PhoneStar Acoustic Insulation
  • 18mm chipboard / OSB / floorboards
  • 235mm solid timber joists
  • 100mm deep x 10-45kg/m³ mineral wool
  • 16mm standard Resilient Bars
  • 15mm Sound Resistant Plasterboard
  • Note: A second layer of 15mm sound resistant plasterboard is required for New Build or Change of Use Separating Floors between dwellings for fire regulations, as shown.

Materials List: (available from our stockists)

  • If existing floorboards or plasterboard have been removed, fill cavity with 100 x 10-45kg/m³ mineral wool
  • 18mm chipboard / OSB / existing floorboards (seal if necessary)
  • PhoneStar Acoustic Insulation on Floor (1200mm x 800mm x 15mm)
  • PhoneStar Eco-tape (50mm x 50M)
  • Resilient bars (3M x 75mm x 16mm deep)
  • Drywall screws to secure resilient bars to joists
  • Sound resistant plasterboard (2400mm x 1200mm x 12.5 or 15mm) – 1 or 2 layers
  • Drywall screws (25mm length) to secure plasterboard to resilient bars
  • Drywall screws (38-42mm length) to secure 2nd layer of plasterboard to resilient bars
  • 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?)

Floor Above

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

2. 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.

3. Ensure the floor surface is clean and even.

4. 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.

5. 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.

6. Install the finished floor surface as per Fitting Floor Finishes over PhoneStar.

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

Ceiling Below

8. On the ceiling below, secure the resilient bars at 400mm centres and perpendicular to joists using drywall screws. Existing plasterboard does not need to be removed. Ensure bar ends do not touch the perimeter walls – leave a 5mm gap. Note: the first and last bars should be approximately 50mm clear of the nearest walls.

9. Screw plasterboard into the resilient bars with 25mm drywall screws, which must not make contact with the timber structure, and leave a 5mm perimeter gap around the perimeter walls. Optionally add the second layer of plasterboard with staggered joints, using 38mm drywall screws (see note above).

10. Seal 5mm perimeter gaps with flexible mastic or acoustic sealant.

11. Finish the plasterboard as required.

12. Consider treating any identified flanking walls with PhoneStar.