Soundproofing Concrete Ceilings with PhoneStar

Soundproofing Concrete Ceilings

Soundproofing concrete ceilings with PhoneStar acoustic insulation is a relatively straightforward task and gives excellent results at reducing both impact sound (such as footstep noise or furniture being moved overhead) and airborne sound (such as conversation, television or music) that travels through concrete ceilings.

Solid concrete ceilings usually provide good airborne sound insulation if they are installed correctly but they tend to perform poorly in terms of impact sound. The best method of reducing impact sound is by laying a resilient layer upstairs directly beneath the floor covering to absorb the footstep noise before it gets into the floor in the first place. However, soundproofing your ceiling may be your only option if you have no access to the floor above e.g. in apartment dwellings.

Sometimes, concrete ceilings allow significant airborne noise to pass through them due to various factors, such as being hollow core floors, having cracks or holes for radiator pipes or experiencing Flanking Noise from adjacent areas.

There is only one option for sound insulating concrete ceilings and this should give excellent results.


Option 1 - Optimum Solution

Decoupled Concrete Ceiling Solution

  • Thickness: 69 – 96mm on Ceiling Below

  • Expected Impact Sound Improvement: 14 – 16 dB approx.

  • Expected Airborne Sound Improvement: 12 – 16 dB approx.

This solution incorporates PhoneStar sound insulation boards being installed on to resilient bars which in turn are installed on to timber battens on the underside of the ceiling. We highly recommend filling this empty space with high density mineral wool to reduce echoes and reverberation. The resilient bars are thin, steel channels that absorb vibrations and greatly reduce sound transmission through the ceiling.

While concrete ceilings are heavy and dense, which is generally good for blocking airborne sound, they can vibrate significantly due to their hardness and rigidity. By decoupling the ceiling, we break the path of sound transmission and therefore significantly improve results. This system offers excellent soundproofing performance for concrete ceilings.

Soundproofing Concrete Ceilings - Decoupled Concrete Ceiling Solution

Construction from Top Down

  • Solid concrete ceiling with plasterboard removed
  • 50 x 50mm or 50 x 25mm (WxH) timber battens
  • Recommended: 25 or 50mm high density mineral wool (45kg/m³) in between battens
  • 16mm standard Resilient Bars
  • 15mm PhoneStar TRI Acoustic Insulation
  • 12.5 or 15mm acoustic plasterboard and skim

Have you also considered Flanking Noise? Flanking Noise is important to consider when installing sound insulation.

Please download the full Installation Instructions for Soundproofing Ceilings before commencing work.

Materials List
  • 50 x 50mm or 50 x 25mm (WxH) timber battens
  • Solid substrate fixings to secure battens to ceiling substrate
  • Recommended: 25 or 50mm high density (45kg/m³) mineral wool between battens
  • Resilient bars Ref: RB1 (3M x 75mm x 16mm deep)
  • Drywall screws to secure resilient bars to battens
  • PhoneStar TRI Acoustic Insulation (1200mm x 800mm x 15mm)
  • PhoneStar Eco-Tape (50mm x 50M)
  • Drywall screws (25mm length) to secure PhoneStar to resilient bars
  • 12.5 or 15mm acoustic plasterboard and skim
  • Drywall screws (38mm length) to secure plasterboard to resilient bars
  • Acoustic or Intumescent Sealant
Brief Installation Instructions
  1. Make existing ceiling sound by removing any loose material.
  2. Secure the 25 or 50mm high battens at 400mm centres with solid substrate fixings. Optionally fill the void between the battens with 25 or 50mm x 45kg/m³ high density mineral wool.
  3. Secure the resilient bars at 400mm centres and perpendicular to the battens with 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.
  4. Screw PhoneStar into the resilient bars with 25mm drywall screws which must not make contact with the timber battens, being careful to leave screw heads just below the board surface. Butt each PhoneStar board up tightly to each other and do not leave any gaps between, or around, the PhoneStar layer. Install the boards in a brickwork formation. See Cutting and Taping PhoneStar Guide on last page of Installation Instructions.
  5. 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.
  6. Seal 5mm perimeter gaps with acoustic or intumescent sealant.
  7. Finish the plasterboard as required.
  8. Consider treating any identified flanking walls with PhoneStar.