Acoustics and Strata Buildings
By Serafina Froio – Strata Project Management
The acoustic performance of a strata building is important and can be easily eroded though seemingly minor changes, creating disturbance and disquiet, or even open warfare, among residents and owners.
According to the Owners Corporation Network NSW, “noise problems are not just the bane of apartment living. Noise is the fastest growing area of complaint and disputes in urban Australia. As well [as neighbourly noise] there maybe noise from the common property aspects of the building itself, pipe, water, or buildings services.”
For the purpose of this article I’m going to ignore building noise and focus on the kind of neighbourly noise – footsteps, scrapping of furniture and dropping of objects – that’s often created or made worse through renovations, but can be avoided with forethought and good management.
If you think of acoustic performance as a core amenity, an intrinsic part of a building and a form of common property, the owners corporation is, in effect, charged with maintaining it. The aim should be to avoid anything that diminishes acoustic performance. That means maintaining a good level of performance where it already exists, and even improving it where the need or opportunity arise.
The trend away from carpet toward harder, and inherently noisier floor coverings, like timber, vinyl and tiles is not going away any time soon. Aesthetics aside, many allergy suffers and pet owners prefer to steer clear of carpet. The pressure is on to find solutions that meet user needs, but don’t diminish acoustic performance. There are lots of useful guides and information about acoustics on the internet including the Association of Australia Acoustical Consultants (AAAC) website http://www.aaac.org.au, but it is a field of engineering so can get very technical!
To keep things simple, when thinking about alternatives to carpet, there are a few important things to be aware of with underlay and insulation. We’ve all heard “the guy in the shop said this underlay is ok”, and it probably is for a house, but not necessarily in your apartment building, where there are ramifications for getting it wrong.
Most underlay products will have a performance rating which is a measure of the noise insulation it provides from the floor to the room below. If it’s an FIIC rating, generally, the higher the number the more insulation it provides. The National Construction Code or NCC (formerly the Building Code of Australia or BCA) now uses an LnTw rating. In this case, generally, the lower the number the more insulation it provides. Some underlay products still use the older FIIC rating and others have adopted the current LnTw rating, so take note of which is being used.
In either case, the manufacturer rating is usually determined in laboratory conditions, which, if you read the fine print, often relates to performance if laid on a concrete floor of a certain thickness with other conditions and construction materials that are probably not the same as your building. So what performs to insulate noise to the right level in the lab, will not on your floor. This could mean your new floating timber floor will not meet your strata’s noise requirements and you might find yourself having to remove the floor, cover it with rugs or even re-carpet.
Occasionally owners will look to building code minimums as a justification for not properly dealing with noise. It’s important to understand the NCC (and BCA to the extent it still applies) is a minimum construction standard for new buildings and many acoustic experts believe it’s insufficient. Chances are your existing building already has better acoustics than the minimum and there is no need for you to agree to or permit that to be diminished.
Here are our practical tips for dealing with acoustics in your building.
- Establish the performance of your building now.
Engage a qualified acoustic engineer and do the requisite testing to understand how the building performs now and decide what the objective is for your building. Many newer buildings already have an AAAC star rating which clarifies the level of acoustic performance, so this stage may not be needed, other than possibly to check that rating is correct and is still the case.
- Develop an Acoustic Specification and a By-Law.
This might include different specifications for different floors or wings, depending on how your building is constructed. This approach provides lot owners clarity about what they can do, including any minimum specifications or approved insulation materials, and can even provide complete solutions – which if done correctly can be ‘deemed compliant’. The benefit of a ‘deemed compliant’ solution is there’s no guessing and no costly mistakes for lot owners.
- Do Post-Installation Testing.
This process is done by an acoustic engineer and is very simple – a special tapping machine taps the floor, the sound is measured in the lot below and the floor either meets the level required or it doesn’t and needs remediation. If you have a ‘deemed compliant’ solution and are satisfied it has been fully implemented by the owner renovating, you might be able to skip this step entirely saving everyone time and money.
Acoustics is an area where it pays to be on the front-foot and consult the experts to develop a solution that’s right for your building. Having the information and clear requirements takes all the guess work out of acoustics and makes it easy for owners renovating and management committees. Where an owner’s corporation has been lax there is a real risk of erosion of acoustic performance and ensuing problems, and that’s not good for anyone.