Sound insulation

We have all been there. Hearing what is being said on the other side of the wall, ceiling or floor. When this happens, sound insulation is poor. But how do you stop sound from spreading through the building? Learn more about sound insulation and its solutions.

Impact sound insulation

Impact sound insulation relates to the reduction of footstep sound from people walking on a floor structure. It is determined by the impact sound level in the room below.

A suspended ceiling system can be used to improve the impact sound insulation and therefore reduce the impact sound level. Improvements are always linked to a specific type of floor structure. 

Impact sound level values

Improvement of laboratory value ΔLn,w according to ISO 140-8 and ISO 717-2.
Improvement Product

 9-11 dB


14-15 dB


15-18 dB

Combison Uno / Combison Duo / Combison dB

22-28 dB

Combison Uno / Combison Duo / Combison dB + Combison XR

The improvements are linked to a homogenous concrete floor of normal thickness (160-200 mm) and with a plastic carpet.  

Vertical airborne sound insulation

The airborne sound insulation of a floor structure can be improved by means of a suspended ceiling system. Measured sound insulation is the same independent if you measure from the room below to the room above or the other direction. Improvements are always linked to a specific type of floor structure.

Vertical airborne sound insulation values

Improvement of airborne sound insulation measured in laboratory ΔRw  according to ISO 140-3 and ISO 717-1.

Improvement Product

4-5 dB


6-9 dB


7-11 dB

Combison Uno / Combison Duo / Combison dB

12-16 dB

Combison Uno / Combison Duo / Combison dB + Combison XR

Installations in the void between the structural soffit and the suspended ceiling, such as piping and ductwork systems, can give rise to noise.

In such cases, a sound insulating suspended ceiling system can be used to reduce the noise to acceptable levels in the room below.

One-way sound insulation values 

Laboratory value Rw according to ISO 140-3 and ISO 717-1.

Product Laboratory value Rw

Combison Duo A

32 dB

Combison Duo E

33 dB

Combison Uno A

27 dB

Combison Uno Ds

28 dB

Combison db A

21 dB

In order to determine the noise level generated by a source in the void, you should ascertain the frequency spectra of the suspended ceiling's sound insulation and the noise source.

Room-to-room insulation

If partitions do not reach the structural soffit a horizontal transmission path for the sound via the void over the suspended ceiling is created. Therefore, traditional acoustic ceilings often provide insufficient sound insulation. In these cases special acoustic ceiling systems are required which offer additional sound insulating properties.

The continuous suspended ceiling is chosen in order to achieve maximum flexibility. However these constructions will give lower sound insulation compared to constructions where the partitions are allowed to penetrate the suspended ceiling or reach all the way up to the soffit. 

When estimating the airborne sound insulation:

  • consider the whole structure

  • note that on site values are lower than laboratory values

Laboratory value/site value

In practice on site, the room-to-room sound insulation (R′w) can be estimated to be 5-8 dB lower than the lowest value in laboratory for the suspended ceiling and partition respectively. This is due to the fact that flanking transmission might occur and some installation details might not be perfect.

Room-to-room sound insulation values

Laboratory value Dn,f,w  according to ISO 10848-2 and evaluation according to EN ISO 717-1.

D n,f,w

Product and size

43 dB

Combison Duo A, 600x600 mm

39 dB

Combison Duo E, 600x600 mm

43 dB

Combison Uno A, 600x600 mm

41 dB

Combison Uno Ds, 600x600 mm

42 dB

Combison A, db 42, 1200x600 mm

28 dB

Master A, 1200x600 mm

29 dB

Master E, 1200x1200 mm

31 dB

Master Ds, 600x600 mm

Improvement of laboratory value Dn,f,w when adding Combison Barrier or Combison XR.

Improvement Product


Combison + 1x40 Barrier


Combison + 2x40 Barrier


Combison + 2x1200 XR


Combison + 100% XR

 Note that site result will be 5-8 dB lower than laboratory value.


Different transmission paths between rooms.

In order to provide reasonable privacy we recommend that normal offices have sound insulation between adjacent rooms of Rw = 35 dB. This requires a suspended ceiling with a laboratory value Dn,f,w  > 40 dB.

The general approach is to combine a sound insulating suspended ceiling with partitions that offer at least the same sound insulation value in a laboratory. Other transmission paths, i.e. ventilation systems, should have an even better sound insulation value.

The values used for the suspended ceiling and the partition should also include possible installations into them, such as lighting and ventilation units or doors and windows. It’s crucial to prevent leakage due to e.g. incomplete sealed junctions between separating wall and flanking surfaces, continuous cable tray or openings around different construction details.