Introduction to Building Acoustics

While an interest in acoustic science and the properties and behaviours of sound are not areas that will fascinate everyone, most of us have at least some interest in building acoustics. That is because we live and work in buildings where unwanted noise can be a real problem. In fact, according to many councils, complaints about noise are the most common cause of neighbourly disputes. Loud noise from a party, TV or even just heavy footsteps can have a serious impact on the quality of life of many people. Different buildings have different acoustic properties and an example of how different surfaces can affect sound comes in the rising popularity of laminate flooring. Previously, fitted carpets were the norm and a good carpet with underlay is an effective sound insulator. When laminate flooring became more popular, these carpets were replaced and all of a sudden the clatter of footsteps and other intrusive noise became a real problem. In fact, the problem was so great that some councils and housing associations banned laminate flooring from their properties.

Understanding sound

To tackle the problems associated with noise requires an understanding of building acoustics. Sound absorption, for example, refers to the amount of reverberation in a room and how that in turn affects sound quality and intelligibility. This is an important quality when designing concert halls, theatres and cinemas. Sound insulation, on the other hand, describes the process of reducing the sound that travels from one area into another. This transmission of sound occurs through airborne and impact, or structure borne, noise. In most buildings airborne sound is created by common sources such as TVs, hi-fis or voices. These sounds travel through the air and are then transmitted through the building’s structure, typically a wall or floor, and emerge into another room. Impact noise comes most often from feet on floors or from dropped objects and moving items.

Tackling the problem

The success of any solutions that are attempted to reduce no