Timber construction in NZ utilising effective sound insulation

Spencer Nicholls, School of Architecture, University of Auckland

In NZ today there is increased awareness of:

  • the advantages of using hard floor surfaces such as tile, parquet or timber strip flooring
  • The implication of higher density living in apartments adjacent to the CBD
  • the power output of the modern stereo system and the prevalence of bass notes in a majority of modern pop music
  • increased external noise levels from traffic, both land and airborne, construction work and farm machinery .

There is also a growing perception that some houses/homes are being built in a manner that reduces unwanted sound and demand for this enhanced construction is increasing. Timber framed multi-residential buildings have enabled speeds of erection and a sustainability of materials that are desirable in this energy conscious age and there are some examples of existing buildings that demonstrate how improved insulation is achieved. However research must continue in order to identify how to provide even better performance.

The problem is not just sound levels associated with the spoken word. Below this speech frequency range (especially less than 125 Hz) the low frequencies generated by heavy stereo bass notes are particularly troublesome for our present style of lightweight structure. Other difficulties are caused by impacts (even light footfalls) generating low frequencies transmitted both horizontally and vertically from one apartment to another.

These regions of any noise spectrum are not covered by the US single number system (STC and IIC) currently specified in the NZ and Australian codes.

Issue 1 Volume 10

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