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*Please Note: PhoneStar was previously branded as Phonewell

Soundproofing exposed timber ceilings with PhoneStar acoustic insulation is a relatively straightforward task and gives excellent results at reducing both airborne sound and impact sound through timber ceilings. This system will surpass building regulations for sound and it will only reduce room height by a minimal amount. This is a very popular ceiling soundproofing solution when there is no access to the floor from above, but the existing ceiling lining has been removed.



Soundproofing Exposed Timber Ceilings


43.5mm – 94mm



Simple, slim solution offering a high performance with absolute minimal loss of living space, where the existing ceiling has been removed. If the lining has not been removed, timber battens can be screwed under the ceiling lining and this will be treated in the same way.



  • Ceiling where existing lining has been removed
  • 100mm x 45kg/m³ density mineral wool fitted within cavity


  • 48mm x 48mm timber battens with 50mm x 45kg/m³ density mineral wool in void
  • 16mm standard Resilient Bars
  • 15mm PhoneStar Acoustic Insulation
  • 12.5mm or 15mm sound resistant plasterboard
  • Second layer of plasterboard may be needed to meet the fire regulations

Materials List: (available from our stockists)

  • 100mm x 45kg/m³ density mineral wool fitted between joists if accessible
  • Optional 48mm x 48mm timber battens if existing plasterboard is in place
  • Optional 50mm x 45kg/m³ density mineral wool between battens, if used
  • Resilient Bars (3m x 75mm x 16mm)
  • Drywall screws to secure resilient bars to joists or battens
  • PhoneStar Acoustic Insulation (1200mm x 800mm x 15mm)
  • Drywall screws (25mm length) to secure PhoneStar to resilient bars
  • Sound resistant plasterboard (2400mm x 1200mm x 12.5 or 15mm)
  • Drywall screws (38mm length) to secure plasterboard through to resilient bars
  • Flexible mastic or Acoustic sealant.


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


Brief Instructions: (have you considered Flanking Noise?)

1. Make existing ceiling sound by removing any loose material.

2. If access to joist cavity, fit 100mm x 45kg/m³ density mineral wool.

3. If using 48mm counter-battens (due to not being able to gain access to the joist cavity), secure them at 400mm centres and perpendicular to the joists. Fill the void between the battens with 50mm x 45kg/m³ density mineral wool.

4. Secure the resilient bars at 400mm centres and perpendicular to joists (or battens if used) using drywall screws. 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.

5. Screw PhoneStar into the resilient bars with 25mm drywall screws which must not make contact with the timber structure, being careful to leave screw heads just below the board surface. Do not leave any gaps between or around the PhoneStar layer. See Cutting and Taping PhoneStar.

6. Screw plasterboard through PhoneStar into the resilient bars with 38mm drywall screws, being careful to stagger joints and leaving a 5mm perimeter gap around the perimeter walls. Optionally add second layer of plasterboard with staggered joints.

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

8. Finish plasterboard as required.

9. Consider treating any identified flanking walls with PhoneStar.