Soundproofing ceiling treatment should only be considered if is not possible to treat the floor above. Acoustic treatment for a floor is generally easier and more effective than treating a ceiling. However, a reduction in both airborne and impact noise through a ceiling can be achieved by the resilient bar system described in this leaflet. This has the effect of isolating the new ceiling from the existing structure, and introduces dense layers of acoustic membrane.
DIAGRAM A: A basic example of how to upgrade the acoustic efficiency of your ceiling without doing anything to the floor above and without adding anything into the cavity space first. Performance would, however, be greatly improved if it is possible to also improve both, or at least one, of these areas (see Diagram B on p.2) sting structure, and introduces dense layers of acoustic membrane.
If you are suffering from noise problems travelling through from your ceiling above it would be wise to firstly try to do something to the upstairs floor before undertaking the installation of a false ceiling. The diagram above shows a basic example of how it looks when you uprate your ceiling without doing anything to the floor above and without adding anything into the cavity space first. If these points are addressed as well, the performance would be greatly enhanced. (see diagram at bottom of page).
The simplest and most effective option for ceiling soundproofing is a system incorporating flexible resilient bars to isolate the new ceiling so that the new ceiling is NOT physically attached to the existing structure. Now there are resilient bars, and there are resilient bars. Cheap resilient bar copies may well be cheap, however they will likely be too stiff to provide the same performance that Robust Detail Approved versions, and actually sound tested versions (like ours) should provide. There are also claims that resilient bars are easily shorted or that they are ineffective but will careful installation you should not have any real issues and pound for pound they will give you the best results for minimal outlay.
Ideally, remove the existing plasterboard and put Acoustic Mineral Wool* in the cavity space before fixing resilient bars to the joists. (If it is not possible to remove the existing plasterboard, add battens to the existing ceiling, incorporating our 5mm-thick neoprene strips between the battens and the existing plasterboard.) The battens should not be thinner than 50mm. Under no cirumstances should you screw resilient bars direct into an existing plasterboard ceiling. Two layers of 12.5mm plasterboard (preferably thicker) should be attached to the resilient bars. The second layer of plasterboard should be offset from the first layer (so that joins are not in the same place) for improved performance. The edges of the plasterboard must NOT touch the existing walls. The small gap should be filled with acoustic sealant. If you want to improve things further then stick a layer of acoustic membrane between the two layers of plasterboard
Additional improvement can be obtained by fixing a layer of our T50 or VL-65 acoustic membrane in between the two sheets of plasterboard. These products greatly damp the plasterboard as well as adding additional mass. The resilient channel system approach can add up to 5–8dB improvement to the overall performance because it reduces the structure-borne vibrations.
If there are restrictions on the work you can undertake to improve your ceiling, a very minimal improvement can be obtained by sticking a layer of T50 acoustic membrane to the existing ceiling, then screw a 19mm sheet of plasterboard on top. This should give around 6dB increase in performance for airborne noise, but will not make much improvement for impact noise. Adding 60kg/m3 Acoustic Mineral Wool slabs between the joists can give a further 3dB improvement, or use our 2FtexPLUS in the joist cavity instead of the mineral wool for further improvement.
You must identify the position of the joists so that you can fix the materials firmly to the ceiling. You will also need to ensure that the perimeter and seams are well sealed with acoustic sealant. This work can more than double the performance of your existing ceiling (depending on the original construction).
If it is difficult to manoeuvre heavy plasterboard sheets into your property then you could use 3 layers of lighter 9mm plasterboard with acoustic membrane sandwiched between each layer.
Our High Grab adhesive is ideal for sticking the soundproofing membrane to the plasterboard before securing the plasterboard to the ceilings. If the joists are at 450mm centres, it may be easier to use 900mm wide plasterboard rather than 1200mm wide sheets, as the edges of the board will coincide with the joists better.
DIAGRAM B: High Performance Floor/Ceiling Solution. This is a guide only. Many installation and site factors will vary, and will affect the results obtained.
The results will depend on workmanship, materials used and methods used, but can sometimes be limited by ‘flanking noise’ this phenomenon is where a percentage of the noise may not only be transmitted directly through the wall but also via adjacent walls touching the separating floor and this can vary from one project to another. It often depends on the existing structure.
For example, if the floor is a concrete floor slab built correctly into the wall then the floor acts as an added resistance to the sound trying to ‘flank’ through the wall; but if the floor slab is not built in but butted up to the wall and the wall leaf is continuous between houses, there will be excessive flanking transmission and it will be necessary to treat not only the floor and/or ceiling, but also the walls. (Diagram C)
Another typical example of bad building conversion is where the end joists run parallel to the party wall. Insulation may even have been installed in the past, but the gap between the end joist and the wall was left unfilled. This may have been because someone thought it wouldn’t make much difference; however, this is not the case – it can make a huge difference.
In situations like this there may be hidden problems which will again limit the improvements that would otherwise be achieved. Without taking things apart to investigate, there is no way of identifying the specific problem. (See Diagram D).
DIAGRAM C: Flanking Noise
Another typical example of bad conversions is where the end joists run parallel to the party wall. Insulation may have even been installed in the past but the gap between the end joist and wall was left. This may have been because someone thought it wouldn't make much difference: wrong, it will! In sitations like this, without taking things apart to investigate, there may be hidden problems which will again limit the improvements that would otherwise be achieved.
DIAGRAM D: Example of poor workmanship, demonstrating lack of understanding and knowledge of, and no attention to, acoustic issues