Noise pollution a growing concern for strata developments
Willow Aliento | 5 October 2017
SPECIAL REPORT: Whether it’s the sound of partying neighbours, constant banging of footfalls overhead or the roaring of traffic heard whenever balcony doors are opened, noise is compromising health and quality of life for many apartment dwellers.
One of the major issues is that the National Construction Code’s impact sound insulation requirements for floors are simply not adequate, according to the Association of Australasian Acoustical Consultants (AAAC).
The association is calling for more stringency, particularly as there’s now a trend for owners and builders of apartments to install hard flooring such as timber, polished concrete or tiles.
Principal of PKA consulting Peter Knowland says there is no other acoustic issue his clients have had that has resulted in “tears running down their faces”.
The noise caused by impacts such as footsteps or chairs being moved on the floor above is, for some, simply unendurable.
AAAC treasurer Richard Haydon says the NCC needs to change and that the Australian Building Codes Board has been ignoring pleas for over a decade.
“We’re seeing more and more owners corporations having to engage in costly litigation to deal with complaints and disagreements as occupants report unbearable noise levels,” Haydon says.
“Apartment occupants are entitled to peaceful enjoyment of their space. Instead, their stress levels increase and neighbour relations are strained, as poorly insulated hard flooring is installed, which would otherwise be acceptable, based on ever increasing reliance on the NCC standard.”
Knowland has lodged a submission to have the standards changed to reflect the AAAC’s Guideline for Apartment and Townhouse Acoustic Rating.
He says this change would result in 12 decibels of additional insulation and be more akin to residents’ expectation of acoustic comfort.
“The Australian Building Codes Board has enacted many wise acoustical measures in the last decade, including sound transfer through walls. We believe that a revaluation of the impact criterion will have a dramatic improvement on people’s quality of life.”
Knowland told The Fifth Estate that the discontinuous construction now used for apartments, coupled with acoustic insulation specifications for party walls, “solved a whole basket full of problems”.
Discontinuous construction means that one apartment’s kitchen does not back onto someone else’s bedroom. Bathrooms are also separated from the neighbour’s bedrooms.
Before this change, he says, one of the biggest noise issues reported was annoyance caused by people washing dishes at night, with neighbours being disturbed by the clattering of cutlery and other washing up sounds.
Now it’s impact noise is the biggest problem, he says.
There are other issues as well, however.
Where apartment buildings are as close together as 18 metres, there are greater noise impacts from adjacent blocks and privacy concerns.
Ideally from an acoustics point of view, blocks would be 40 metres apart, but then the whole discussion about needing to house as many people as possible and needing to maximise returns from sites arises.
When thermal performance and acoustics fight
Thermal performance and acoustic performance can also end up in a stoush.
For example, double glazing is recommended in many climate zones as part of the thermal performance solution. But the double-glazed units that work best for thermal performance, with a 12mm air gap, can actually worsen acoustic protection, particularly for low frequencies such as passing trucks.
The best double glazing unit for acoustics is one with at least a 50mm gap between the glazing panels. Knowland says Section J energy modellers argue that this gap reduces thermal performance as it allows air to circulate within the gap and therefore transfer heat or cold. Apparently there’s butting of the heads going on over this on some projects.
Another controversial topic is whether only heavyweight construction, such as concrete or masonry, can deliver acoustic protection.
This discussion reared its head when the ABCB upgraded acoustic requirements for walls – part F5 in the Building Code of Australia – in 2004.
“There were some arguments that lightweight walls wouldn’t [perform], and that [upgrading requirements] would be more expensive.”
But the industry adjusted to the change, and Knowland says that research has since shown that a 145mm thick lightweight wall can actually improve acoustic performance compared to a 400mm thick brick wall.
The advantage for developers and builders of the lightweight walls is gaining more floorspace within the building envelope, he says. The walls are also cheaper to build.
“Brick with plasterboard is a recipe for disaster.”
No thermal benefit to floor insulation
GW Environmental Solutions director, Gary Wertheimer, says that when the acoustic performance of an apartment is originally assessed, any carpets are factored in as part of the sound insulation.
Remove that, and it will not be performing as specified.
As to whether there would be a thermal benefit from increasing insulation between floors, Wertheimer says no.
Because most people keep their apartments at around the same temperature, 21 degrees, there is very little heat gain or loss vertically, he says. It’s the insulation in external walls that is key for thermal performance.
And insulation at the edge, where the floor and wall both meet the exterior facade probably “overperforms” acoustically in terms of requirements.
Renovations creating hell for neighbours
Beyond new builds, renovations are a problem. When an owner decides to take up the carpets and either expose timber, or add timber, they are making life hell for their neighbours, Knowland says.
At a recent strata meeting, he says, one owner was claiming that if they wouldn’t be able to sell their apartment if they didn’t put down a timber floor.
“But if they do, in 10 years time they won’t be able to sell it.
“The consequences of impact noise are significant – it’s the only area of acoustics where people are in tears about it, because they can’t put up with it anymore.”
He says the solution – if owners simply must install or reveal timber floors – is to lay carpet or other acoustic insulation under the timber.
This can be a significant cost increase, he says.
But it also means that owners will be abiding by the strata bylaw that says every resident has the right to “peaceful enjoyment” of their unit.
Noise becoming an increasing problem
Strata Communities Australia national chief executive Erik Adriaanse says noise is increasingly becoming a problem in strata communities.
One of the reasons is strata multi-residential has a mix of downsizing older owner-occupiers, and young single people “upsizing”, he says.
The younger residents, whether renting or owning, are more likely to want to play music, stay up late and have parties compared to downsizers.
Adriaanse says the challenge is to build something that can accommodate both lifestyles.
That means paying attention to sound-proofing.
In terms of managing noise, he says that while strata corporations can write to residents in response to complaints such as a barking dogs or noisy gatherings, people being complained about are “not always going to take it well”.
We need to raise standards, but again it’s developers in the way
Part of the solutions is to increase the impact sound insulation requirements in the National Construction Code.
“But it’s a question of whether anyone can make it happen,” he says.
“If the requirement for acoustic insulation goes up, then costs will go up and developer profits will go down.”
There is also the vexing question of who actually decides a project has achieved a specified standard, he says.
“Is it a private certifier or a public one?
“We’ve got the same issue with cladding. There are a lot of very nervous people out there.”
Adriaanse points out that many people have borrowed 90 per cent of the cost of their apartment, and if they need to find $30,000 as their share of the cost of remediating flammable cladding, the bank is not going to be impressed.
The value of the building – and each apartment – also goes down.
Building standards – and how to control them – need to be put “right in front of the government’s face”.
Adriaanse says when people are looking to buy an apartment, whether built or off-the-plan, they should query the sales agent on the acoustic insulation specifications.
“If consumers can become aware they can ask the question.”
The same goes for things like cladding – if the sales agent does not have the information, they need to go to the builder and obtain the specifications to show the potential buyer.
Where an existing building has noise issues, for example from being near a busy street, owners corporations can look at mitigation strategies such as introducing greening to create an acoustic dampener.
“The executive committee should look for answers that make for better community living,” Adriaanse says.
Why noise is a big deal beyond annoyance
According to the Australian Academy of Science, exposure to prolonged or excessive noise has been shown to cause health problems ranging from stress, poor concentration, productivity losses in the workplace, communication difficulties and fatigue from lack of sleep, as well as serious issues such as cardiovascular disease, cognitive impairment, tinnitus and hearing loss.
In 2011 the World Health Organization released a report titled Burden of disease from environmental noise that showed at least one million healthy years of life are lost each year in Europe due to noise pollution from sources including environmental noise from planes, trains and vehicles and other city sources.
The Academy makes a range of recommendations to combat noise pollution in terms of urban planning and improved building design.
- using dead-end streets and car-free malls as sites for residential complexes
- depressing freeways and arterial roads below the level of adjoining residential areas
- using roadside noise barriers
- creating maximum separation between roads and new buildings
- siting high-rise buildings at the front of a development, thereby providing acoustic shielding for any low-rise buildings behind them
- using natural topographic features to the best acoustic advantage
- Sealing of windows and doors will reduce leakage of sound into a building
- Solid cored doors are most effective at blocking noise from the outside world