Plasterboard & Class A Sound Absorption

The difficulty of plasterboard is that it is a hard material and sound bounces on hard materials or to use the technical term it reverberates. Therefore whilst it has flexibility to produce solutions to on site details it is generally not the material of first choice when it comes to creating a comfortable environment needing high acoustic absorption. Perforated plasterboard, the logical solution, helps but generally is seen as having limitations in how much absorption can be achieved and is then disregarded when the highest requirement is necessary. But there is a solution – V-Cut with its partner Vogl can bring a solution that will give a class A rating (the highest).

Sound is very simply vibrations – an oscillating pressure wave. The pressure level of the sound is defined in decibels (dB) and the wave is carried in a frequency range (Hz). The human ear can hear sounds in the decibel range 0 to 120 dB and the frequency range of 20 to 20,000 Hz. Without getting too technical, and acoustics is a highly technical subject, when it comes to the choice of materials EN ISO 11654 defines sound absorption in the classes A-E with A being the highest absorption rating. Essentially each class defines how much of the sound wave is absorbed across the different frequencies and therefore how much bounces around.

The major drywall manufacturers rate the sound absorption of their plasterboard systems between class B, C and D. This may be fine for most applications but there are buildings that require more such as schools and hospitals, for example, where the room’s ambient noise levels heavily influence learning and understanding. In the UK, Building Bulletin 93 (BB93), governing the design and construction of schools, is clear that for large lecture theatres, music rooms, resource areas, libraries, drama studios, public areas and certain other rooms a high absorption rating may be required, up to Class A, and the ceiling represents one of the main approaches to achieving that.

So achieving Class A with a plasterboard ceiling clearly is a challenge if the major manufacturers find it hard. All plasterboard manufacturers approach sound absorption through the use of perforated boards. The perforations allow sound to travel through the board and be absorbed into the linings behind hence the degree of perforation influences the amount of sound that has the chance to be absorbed relative to that which bounces back into the room. With the right amount of perforated area and an appropriate lining behind, we achieve an absorption rating of 0.90 or absorption Class A. In addition, with our acoustic plaster finish, we achieve an even better absorption rating of 0.95 whilst retaining a monolithic appearance. If you need assistance in this area we shall be happy to help.

For more on our acoustic plasterboard and perforation patterns go to our perforated ceilings page.