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How to achieve a AAAC 6 Star rating for your hard flooring

By April 28th, 2022Blog

Achieving a AAAC (Association of Australasian Acoustical Consultants) 6 Star (LnT’w 40) acoustic impact rating in most apartments is possible. However, there are certain things you need to be aware of to ensure compliance.

There are several requirements with regards to floor coverings and their acoustic ratings. To better understand the context and meaning of the requirements, we provide this overview of apartment flooring and how impact noise relates to apartment owners.

Impact noise from people walking in their apartment, is one of the few noise issues that almost exclusively affects someone other than the person generating the noise

The following factors determine how impact noise is perceived:

  1. What is the impact source and is it on carpet or hard flooring? Are people wearing heels? Is the impact heavy? Does the apartment above have hard flooring throughout which means impact noise could be audible anytime someone is walking around? Or does it have hard flooring in only a small area.
  2. The flooring type and what is the underlay, e.g., carpet, timber, tiles etc. What is the quality of the underlay under the hard flooring (there are many different types)?
  3. What is the thickness of the concrete slab?
  4. Is there is a ceiling void below – and how big is it?
  5. What is the ceiling suspended from? Is this a lightweight steel grid system or timber battens directly fixed against the concrete slab?
  6. What is the ceiling type? Is this solid plasterboard, timber or a perforated ceiling?
  7. Are there penetrations or other weaknesses in this ceiling? For example, supply & return air grilles, downlights, bulkheads with lower performance, access panels etc.
  8. Is the receiver space very quiet? This would result in everything you hear sounding louder than if your apartment was next to a busy road where some of the impact noise is masked by traffic noise. The time of day is also important. At night when there is less noise outside, impact noise will sound more prominent.
  9. How sensitive is the person below to impact sound? What is the expectation of the acoustic amenity?

Strata By-Laws: 

Each apartment building will have its own strata plan and associated by-laws. Often older by-laws may have a simple clause such as “any new floor should be covered or otherwise treated to an extent sufficient to prevent the transmission from the floor space of noise likely to disturb the peaceful enjoyment of the owner or occupier of another lot.” These types of by-laws can be difficult to access as subjective interpretations of sound can vary greatly. 
By-laws can also include clauses that specify particular sound level performances for floors, as well as different criteria for various rooms.

For example, “An owner of a Lot must ensure that all floor spaces within all Bedrooms of the Lot is covered or otherwise treated to an extent sufficient to achieve a minimum AAAC (Association of Australian Acoustical Consultants) 6 Star rating.” 
When the by-laws require a AAAC 6 Star rating, an acoustic impact test should be conducted by a qualified acoustic engineer that is from a member firm of the AAAC, prior to purchase and installation of a new floor system.

How do acoustic underlays make in the proposed floor system and what are the differences between them?

There are a lot of different types of underlays available, standard 2-3mm foam or rubber-based underlays that are used simply as an intermediary layer to provide a stable base under the flooring, to acoustic underlays that treat impact noise with various effectiveness.

Acoustic underlays can also be made of foam or rubber, but the typically don’t have the superior acoustic performance of polyester-based underlays such as AngelStep by Acoustica.

AngelStep underlays made of polyester have a higher rate of absorption of impact noise than foam or rubber alone which only spreads the impact noise. This allows the AngelStep underlays to achieve a higher acoustic rating such as LnT’w 40 (AAAC 6 Star) in most applications.

AngelStep is available in various formats that are suited for different flooring types with some that have an integrated acoustic barrier for controlling airborne noise as well as impact noise making them suitable for timber sub-floors rather than concrete slabs.

Most underlay manufacturers 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.

AngelStep underlays are regularly testing in-situ, which means that the resulting test performance is a more accurate indication of how they treat impact noise in real-life conditions.

Angel Step acoustic underlays

AngelStep acoustic underlays are widely known in the market, from acoustic consultants, architects and flooring specialists as the best performing underlay for use in multi-residential applications.

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. This is where the expert team at Acoustica can assist in choosing the correct version of AngelStep to ensure compliance with the required acoustic performance rating.

Contact Acoustica at or give us a call to discuss on 1300 722 825,

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