Timber floors are often installed in high rise and unit developments where it is necessary to reduce to acceptable levels the noise transmission through to the dwelling below. due to this, timber and other similar hard flooring products are often laid on an acoustic underlay. ( This is also recommended for upper floors in houses).
There are two main types of noise to be considered.
The first is the higher frequency noise from music, phones ringing, people talking , televisions and the like. This type of noise is controlled by mass and and with timber floors over concrete slabs, the mass of the slab generally provides sufficient control for this not to be a problem.
The second type relates to the noise associated with the lower frequency vibrations. This includes foot fall noise and particularly from stiletto heels but also from sub-woofers in entertainment systems.
To control the low frequency vibrations, shock absorbing acoustic underlays play an important role to reduce noise transmission to an acceptable level. However, the choice of underlay and system used will also depend on many factors including the type of flooring, slab thickness, ceiling heights and the type of ceiling system beneath.
Sound pressure is measured in decibels (dB) and an increase or decrease is perceived by us as a change in loudness. Most of us would notice a change of 3dB and a reduction of 10dB would sound about half as loud. The lower the figure the better the attenuation and the better the result.
The Building code of Australia (BCA) requires the LnTw (plus a modification factor Ci) to be not more than 62 dB for floors separating dwellings.
Strata Management Requirements
Although the above provides the necessary guidelines for construction to meet BCA
requirements, we must also consider the Strata Schemes Management Act. This act permits an apartment block to have its own set of by-laws which owners must comply to and as such these can add additional restrictions and in some instances the requirements are much less
well defined than the BCA requirements.
Oakland Timber Floors provides many types of timber floor underlayment to meet our clients' requirements and We can help guide you through the perils of acoustic requirements. The process, usually begins by talking to your strata management and gathering the information about your building (subfloor construction and thickness, celling information, by-law ratings, previous tests etc.). We then take this information to the acoustic divisions of our manufacturers and find a system that should meet your requirements. Sometimes, previous tests will give enough of an indication that the rating will be met (for example, if there is a test with 5mm rubber in a building with similar factors to yours, then a similar result could be expected for your floor). If no previous test exists, then we might need to employ the services of an acoustic engineer to find a suitable system.