Acoustic flooring: choosing a quieter floor

A floor changes more than the view across a room. It changes how footsteps sound in the hallway, how a chair moves across the dining area and what the neighbour below hears.

Choose acoustic flooring as a complete construction: the surface you see, the layers beneath it and the building around it. A promising number on a sample is a starting point. The useful question is whether its test describes the floor you intend to install.

What makes a floor “acoustic”?

A floor is acoustic because of a test result, not because of what it is made of. The result belongs to a whole system: the floor covering, the underlay or backing, the slab or joists it was tested on, and any ceiling below. Change one layer and you have a different floor.

The building code works the same way. Clause F7D5 of NCC 2022 Volume One sets its rating for “a floor”, not for a board or an underlay. The only underlay named in the deemed constructions of Specification 28 is carpet underlay, and even that is rated as part of a “200 mm thick concrete slab with carpet on underlay”.

An acoustic flooring claim should identify the tested build-up and its stated result. A board with foam on the back is one part of that system.

Floors deal with two kinds of noise. Impact sound is footsteps, dropped objects and chairs dragged across the floor above. The ABCB sound handbook calls this structure-borne sound and says it is reduced by isolating the vibration with a resilient layer, which is the job of an acoustic underlay. Airborne sound is voices, TV and music, and it is rated separately (Rw in a laboratory, DnT,w on site). Hard floors cause trouble mainly through impact sound: the same handbook (section 5.1.1) warns that when carpet is replaced by a hard floor, the loss of impact isolation “can result in as much as 25 to 30 dB extra sound transmission”.

If your problem is noise from upstairs in general, our guide to soundproof flooring covers what a floor can and cannot fix.

What do “acoustic insulation flooring”, “acoustic rated flooring” and “acoustic floorboards” mean?

These are the same question in different words. “Acoustic insulation flooring” usually means a floor that reduces sound reaching the apartment below; the formal term is “impact sound insulation”. “Acoustic rated flooring” should be supported by a published result for a named construction. “Acoustic floorboards” usually means boards sold with an attached or named underlay.

All three land on the same answer: a number from a test, for a named build-up. Ask which rating it is (a laboratory Ln,w or ΔLw, or an on-site L’nT,w), which build-up was tested, and where the report is. If the seller cannot answer all three, the label tells you nothing about your floor.

Tested systems versus marketing claims

A marketing claim is a number without its conditions. A tested system is the same number with the standard, the build-up, the slab and the tester attached.

What does a real acoustic test report look like?

A real report names the test standard. A laboratory impact test is done under ISO 10140-3:2021 in a facility where sound paths around the floor are suppressed. An on-site test is done under ISO 16283-2:2020, which replaced ISO 140-7. Either result is turned into one number under AS ISO 717.2:2024, the Australian adoption of ISO 717-2:2020. For impact figures, lower is quieter.

Both tests use a standard tapping machine. It has five hammers that drop 40 mm onto the floor, again and again, while microphones measure the sound in the room below, as described in a 2014 Queensland field study. ISO 10140-3 says the machine simulates “human footsteps when a person is wearing shoes”.

The report should then state the result type. A laboratory result is an Ln,w (the whole floor) or a ΔLw (the improvement from a covering or underlay). An on-site result is an L’nT,w, which the NCC and many by-laws write as LnT,w. The ABCB handbook (Appendix D.1) explains why an on-site result can be worse: sound travels around the floor through walls, ceilings and penetrations, and workmanship varies.

The report should also describe the slab and the ceiling, because they change the number a lot. In South-East Queensland field data from the Inter-noise 2014 study, bare 180 mm slabs with no ceiling measured L’nT,w 68 to 76, and bare 200 mm slabs measured 65 to 69. In the same study, one layer of 13 mm plasterboard ceiling improved a bare 190 mm slab by 14 points.

Is an underlay’s ΔLw the same as a floor rating?

No. Under AS ISO 717.2:2024, ΔLw is the difference in impact level measured on a bare heavy reference floor without and with the covering. It is a laboratory improvement figure, and higher is better. Our acoustic underlay guide explains how to read one.

You also cannot subtract it from your building’s figure. In the Inter-noise 2014 case study, the same five underlays under tile improved a bare slab by 4 to 17 points with no ceiling, but by only 4 to 11 points with a plasterboard ceiling. The covering on top matters too: in the same field data, tiles stuck straight to the slab improved it by 0 to 2 points, while floating timber on underlay improved it by 15 to 22 points.

Why is “5 star underlay” not a floor rating?

AAAC star ratings come from the Association of Australasian Acoustical Consultants’ Guideline for Apartment and Townhouse Acoustic Rating (Version 1.0, June 2017). The guideline says the stars measure “the actual installed performance” of a floor in a completed apartment, and only an AAAC member firm may issue a star rating certificate. For floors between tenancies, 5 star means an on-site L’nT,w less than 45 and 6 star means less than 40.

A roll of underlay is not a finished apartment. The AAAC explanatory note (Version 2.0, May 2023) says “it cannot be claimed that any one building product in isolation (especially an acoustic underlay), is guaranteed to achieve a certain acoustic rating or AAAC Star Rating”. It adds that manufacturer claims “should be evidenced by laboratory or field test results and the complete floor/ceiling system build-up clearly listed”. A “5 star” or “6 star” label should therefore be supported by evidence for a named complete construction; the label alone does not prove the claim. Ask for that report, and see acoustic ratings explained for every threshold.

What does NATA accreditation tell you?

NATA, the National Association of Testing Authorities, accredits testing laboratories in Australia. NATA says accredited organisations may put its endorsement on reports only for activities inside their scope of accreditation, and “use of the NATA endorsement is not permitted on reports of testing outside the scope”. You can check a lab’s scope with NATA’s Find Organisation search.

A NATA endorsement tells you the lab was accredited for that test, not that the tested build-up matches your apartment.

What should you ask any acoustic flooring supplier?

Send these ten questions by email and keep the replies.

• Can you send the full test report, not a brochure page or a summary figure?
• Is the figure a laboratory result (Ln,w or ΔLw) or an on-site result (L'nT,w)?
• Which standard was used: ISO 10140-3 in a laboratory, or ISO 16283-2 (or the older ISO 140-7) on site, rated under ISO 717-2?
• What exact build-up was tested: which board, which underlay and thickness, and which adhesive or fixing?
• What slab type and thickness was it tested on, and was there a ceiling below?
• Who carried out the test, who paid for it, and on what date?
• Does the report carry a NATA endorsement, and is the test inside that lab's scope of accreditation?
• If you claim a star rating, which AAAC member firm issued the certificate, and for which building?
• Does the figure include + CI, and is it the same type of rating my by-law uses (L'nT,w or FIIC)?
• Which installation details did the result depend on, such as a gap at the walls or an isolation strip under the skirting?

How do you read an acoustic test certificate?

Certificates differ in layout, but the fields are the same. The table follows the reporting items in the ABCB handbook (Appendix D.3.3) and the statement of results in AS ISO 717.2:2024. The handbook (Appendix D.1) also notes that the NCC dropped the CI term from its floor rating in 2016.

Acoustic flooring by floor type

The figures below are on-site results from published tests in stated conditions: examples, not promises. For a comparison of floors, see best flooring for apartments.

Hybrid

For a rigid-core hybrid proposal, identify the attached backing, any separate underlay and the floating installation method. Request the full acoustic report for that construction and compare its slab and ceiling with your building. An attached pad alone does not establish the finished performance. See acoustic hybrid flooring and acoustic underlay for hybrid flooring.

Laminate

Acoustic laminate flooring is a floating click floor on a foam or similar underlay, sometimes attached to the board. Ask for the report for the exact board and underlay pair rather than assuming a category result. See acoustic underlay for laminate flooring.

Engineered timber

Engineered timber is usually floated over an acoustic underlay, or glued to an acoustic mat on the slab. In a Brisbane tower, floating bamboo and engineered timber systems between 41 and 59 mm thick in total measured LnTw 41 to 52 on a 180 mm slab, in the bedroom of another apartment (Body Corporate for Admiralty Towers II v Johnson [2017] QCATA 29 at [12]). In South-East Queensland field data, floating timber on underlay improved the bare slab by 15 to 22 points (Inter-noise 2014). Check that the fixing method in the test matches yours. See acoustic underlay for timber floors.

Solid timber

Solid boards are fixed down, so acoustic timber flooring in solid boards needs a resilient layer under the boards that suits the fixing method. The published Australian field data we found does not separate solid from engineered boards. In the same Brisbane tower, an owner’s proposed French oak floor on a dimpled rubber underlay tested at about LnTw 51, against a by-law limit of 45 (Admiralty Towers II). Check the tested board thickness and fixing, and read acoustic underlay for timber floors.

Vinyl and LVT

For vinyl sheet, plank or tile (LVT), check the backing, underlay and fixing method together. In South-East Queensland field data, 3 to 9 mm vinyl on underlay improved the bare slab by 8 to 21 points (Inter-noise 2014). Those results describe the tested constructions, not a category-wide promise. Ask the vinyl maker to confirm the proposed underlay and installation system in writing.

Tile

On its own, tile does almost nothing for impact noise: tiles stuck straight to the slab improved it by only 0 to 2 points in the Inter-noise 2014 field data. With an acoustic underlay, the improvement was 5 to 15 points. In the same study’s case study, tile on five different underlays measured L’nT,w 52 to 65 on a 190 mm slab with no ceiling, and 44 to 51 with a plasterboard ceiling. Check the tested tile, adhesive and underlay. See acoustic underlay for tiles.

Carpet

Carpet on underlay is the quiet reference floor. Existing carpet on underlay in the Brisbane tower measured LnTw 33 (Admiralty Towers II at [12]), and the NCC’s deemed construction of a 200 mm slab with carpet on underlay meets Ln,w 62 (Specification 28, S28C8(3)). That is why the ABCB handbook (section 3.2.2) says carpet “should not be replaced with acoustically non-compliant hard floor coverings”. See acoustic underlay for carpet.

Cork, rubber and linoleum

Cork is used as a floor finish and as an underlay. We found no independent published Australian test for cork floors, so ask for the report and the build-up.

Rubber is usually the acoustic layer itself, as a mat under tile or timber, and a finish in gyms. See rubber acoustic underlay, which also covers cork underlays.

Linoleum is glued down in sheets or tiles, and some products have a bonded backing layer. We found no published Australian test for linoleum build-ups, so ask for the report and check the tested build-up.

Where is acoustic flooring required, and by whom?

New buildings: the NCC

For new work, clause F7D5 of NCC 2022 Volume One says a floor in a Class 2 or 3 building “must have an Rw + Ctr (airborne) not less than 50 and an Ln,w (impact) not more than 62” if it separates sole-occupancy units, or separates a unit from a plant room, lift shaft, stairway, public corridor, public lobby or parts of a different classification. Those are laboratory figures. The on-site performance requirement (F7P1, verified under F7V1) asks for LnT,w not more than 62 and DnT,w + Ctr not less than 45.

NCC 2025 keeps the same clause numbers and figures. The ABCB adoption table shows Victoria, Western Australia and the ACT adopted it on 1 May 2026, and NSW, Queensland and South Australia adopt it on 1 May 2027. The Northern Territory has not adopted NCC 2025, and its variation of Part F7 in NCC 2022 asks floors between units for Rw 45 with no impact figure.

The NCC is a minimum. A Queensland appeal tribunal said in McLeod v Body Corporate for Stradbroke Tower and Villas [2015] QCATA 146 at [29] that the BCA “is a minimum construction standard” and “does not set levels for the purposes of good neighbourly relations”.

Existing apartments: by-laws

In an existing apartment, the rules usually come from the by-laws and the committee’s approval. In NSW, “installing or replacing wood or other hard floors” is a minor renovation under section 110 of the Strata Schemes Management Act 2015, which needs owners corporation approval by resolution at a general meeting (see strata flooring rules in NSW). In Queensland, the government’s body corporate guidance says “some bodies corporate have by-laws which say owners need approval for changes to flooring” (see body corporate flooring rules in Queensland).

By-laws can be strict. The Admiralty Towers II by-law asked for LnTw not more than 45 (QCATA 2017), and some Queensland by-laws have used the American FIIC scale (McLeod). Ask a certifier whether your floor change is also building work. Our strata flooring rules guide covers each state, and the strata flooring checker lists what to ask the committee for in writing.

Commercial buildings and gyms

Part F7 applies only to Class 2, 3 and 9c buildings (NCC Part F7). A floor between apartments and a shop, office or car park is still covered, because under NCC Part A6 those are different classifications. In a purely commercial building, Part F7 sets no floor rating.

Gyms need care. The tapping machine simulates footsteps in shoes; ISO 10140-3 uses a separate heavy, soft source for bare feet or children jumping, and ASTM E989 says its rating “does not deal with low frequency sounds below 100 Hz”. So a normal floor rating says little about dropped weights; ask an acoustic consultant.

Who tests and certifies acoustic flooring in Australia?

AAAC member firms are acoustic consultancies. Only an AAAC member firm may issue an AAAC star rating certificate (AAAC guideline, section 2.0), and the AAAC lists its member firms by state. The AAAC explanatory note says that, for certainty, the finished floor should be tested and a certificate of compliance provided by an AAAC member.

NATA-accredited laboratories may put the NATA endorsement only on reports of tests inside their scope of accreditation, which you can check with NATA’s Find Organisation search.

Your by-law may name who can do the test. The Admiralty Towers II by-law asked for a report from “a suitably qualified Acoustical Consultant who is a member of the Australian Acoustical Society” (QCATA 2017). We do not recommend any firm.

How do you compare acoustic flooring quotes like for like?

Compare itemised quotes for the same construction and preparation work:

1. Same build-up. Each quote names the board, underlay, thickness and fixing, and matches a test report.
2. Underlay. Attached, separate, or missing from the quote.
3. Preparation. Old floor removal, slab levelling and disposal are listed, not assumed.
4. Perimeter. The gap or isolation strip the test depended on is included.
5. Testing. If your by-law needs an on-site test, who arranges it and who pays.
6. Warranty. It covers the build-up as quoted.

A cheaper quote that changes the underlay or fixing is a different floor from the one your committee approved.

How should you narrow the shortlist?

Keep the room finish and the technical specification together. Take two or three samples into the home, then ask for a complete floor build-up for each: board, backing, any separate underlay and fixing method. A finish you like is worth investigating; it is not a reason to skip an incompatible layer.

Compare floating floors by construction, use the test report reader to identify the evidence, and confirm the written approval before ordering.

How should you narrow the shortlist?

Keep the room finish and technical specification together. Take two or three samples into the home, then ask for a complete floor construction for each: board, backing, separate underlay if permitted, and fixing method. Compare floating floors by construction, use the test report reader to identify the evidence, and confirm the written approval before ordering.