Acoustic hybrid flooring: beyond the star rating

Hybrid flooring is often shortlisted for an apartment because its timber-look boards and attached backing appear to make the specification straightforward. The acoustic paperwork deserves just as much attention as the finish.

An attached pad, board thickness and a star on a brochure tell you different things. Read them together with the installation guide and the complete test report before deciding whether the system belongs in your home.

What is acoustic hybrid flooring, and why is it sold for apartments?

A hybrid plank is a rigid board that clicks together. It has three parts: a waterproof core, a printed decor under a clear wear layer, and a thin pad bonded to the back. Godfrey Hirst’s CodeMark certificate describes its core as “a composite of calcium carbonate and PVC”, which is what SPC (stone plastic composite) means, with a 1.5 mm acoustic backing and a wear layer of 0.3 mm or 0.5 mm. Preference Floors sells a WPC version, Iconic, with an attached 1.5 mm pad.

On a hybrid, “acoustic” almost always refers to that pad. The pads we found were IXPE foam (a cross-linked polyethylene), cork, rubber and unnamed foams, from 1 mm to 2 mm thick. Woodland Flooring’s Highland range has a 1 mm IXPE pad. The Nouvelle Acoustic data sheet lists a 1.5 mm cork back layer. Hybrid Floors Australia describes a 1.5 mm rubber pad on its 6.5 mm range and a 2 mm pad on its 9.5 mm range.

Makers give practical reasons to use hybrid in apartments. It floats, so nothing is glued to the slab. It can go over many existing hard floors, such as well-bonded ceramic tiles. The core is waterproof. Godfrey Hirst says all of this on its hybrid page and in its installation instructions.

The pad matters because a hybrid often replaces carpet. The ABCB sound handbook (section 5.1.1) warns that when carpet is replaced with a hard floor, this “can result in as much as 25 to 30 dB extra sound transmission”. That extra footstep noise is what a flooring by-law is written to stop.

Do you need a separate underlay under a hybrid with an attached pad?

Every hybrid we checked is designed to float on its own pad. People usually ask about a second underlay after a committee asks for a better number. The makers do not agree on this, so follow the rule in your maker’s installation guide:

• Signature Floors: “no additional underlay is allowed. Use of an additional underlay will void the warranty” (installation guidelines, revision 05).
• Australian Select Timbers (Nouvelle Acoustic): any additional underlay voids the warranty unless the maker approves it first. For apartment jobs, you need “a formal letter of authorisation from the manufacturer” (installation instructions, data sheet).
• Preference Floors: no extra underlay in a house. In a multi-residential building, you can put a rigid cork or rubber mat of “1.5mm > 3mm maximum” under the attached pad. A thicker underlay, or a soft foam one, voids the warranty (installation guide, July 2024).
• LICO: no extra layer is needed. If you add one, it must have a compression strength of at least 200 kPa (installation manual).
• Godfrey Hirst: we found no rule either way in its August 2026 instructions, so ask the company in writing.

The reason for these rules is the click joint. Signature’s guidelines say soft underlays “will diminish the products inherent strength in resisting indentations & lock integrity”. Preference’s guide says an extra underlay in a house “will compromise the click system and void the warranty”.

Does a second layer help? Two field tests published by one supplier give different answers. Preference’s Iconic plank measured L’nT,w 39 on its own pad. With a 3 mm Regupol mat added, it measured 34. Koikas Acoustics tested it in a Liverpool (NSW) building in 2021 (summary sheet). The Aspire 8 mm plank measured 42 on its own and 43 with a Regupol Sonus Multi 3 mat. Contrix tested it in a Zetland building in 2024 (full report). So the second layer gave 5 points in one building and no gain in the other.

What changes between 6.5 mm and 9.5 mm hybrid?

Hybrid is often sold in 6.5 mm and 9.5 mm total thicknesses. Hybrid Floors Australia publishes both build-ups. Its 6.5 mm range is a 5 mm core plus a 1.5 mm pad. Its 9.5 mm range is a 7.5 mm core plus a 2 mm pad. Both have a 0.5 mm wear layer. So most of the extra 3 mm is core, with a pad that is 0.5 mm thicker. The wear layer, which decides how the surface lasts, is the same.

Koikas Acoustics tested both on site, on slabs of about 200 mm with a suspended plasterboard ceiling below. The 6.5 mm plank took a bare floor in Belfield, NSW, from L’nT,w 60 to 47 (2022 report). The 9.5 mm plank took a bare floor from 58 to 41 (2023 report). The thicker plank improved its floor more: 17 points against 13. But the tests were 14 months apart, over bare floors that measured differently, and both used a sample of about 1 m². So they cannot show how much of the difference comes from thickness alone.

Thickness is not the largest variable. Godfrey Hirst’s 5.8 mm, 6.3 mm and 6.5 mm planks all measured L’nT,w 47 on the same 270 mm slab, according to its CodeMark certificate. The same certificate gives Day Design’s predictions for one 6.5 mm plank: 54 on a 200 mm slab with no ceiling, 49 with a 10 mm plasterboard ceiling, and 46 with R2.5 insulation added above that ceiling.

Signature Floors’ acoustic guide shows the same pattern for its 6 mm hybrid. The guide labels its predicted figures Ln,w. They go from 60 on a 120 mm slab with no ceiling down to 35 on a 200 mm slab with two layers of plasterboard and insulation. The slab and the ceiling below you change the number more than a few millimetres of plank.

A thicker plank does not change three things: you still need the perimeter gap, you still follow the maker’s underlay rule, and your by-law is still judged on the floor as laid in your building.

What do “5 star” and “6 star” hybrid claims mean?

Star ratings come from the Association of Australasian Acoustical Consultants’ Guideline for Apartment and Townhouse Acoustic Rating. For floors, the rating is the on-site L’nT,w of the finished apartment. 5 star is less than 45 and 6 star is less than 40. The guideline says the star system “measures the actual installed performance”. So a star belongs to a floor in a building, not to a box of planks.

A “6 star acoustic hybrid” claim should be supported by a report identifying the complete tested construction. The label alone does not establish that the evidence exists or applies to your building. Some sellers publish that test. Wonderwood publishes a one-page field sheet for its 9 mm plank. It shows L’nT,w 36 in a Wolli Creek apartment, measured by Contrix in November 2022, over a slab estimated at 200 to 220 mm and a plasterboard ceiling. Other sellers publish only the claim. For example, we found no report behind the “6 Star AAAC” claim on Flooring Works’ 6.5 mm range page. For how the stars compare with the building code, see acoustic ratings explained.

Who can issue an AAAC star rating?

The guideline says: “Only a AAAC member firm may issue a AAAC Star Rating Certificate” (AAAC guideline, section 2.0). The AAAC does not rate products. Its explanatory note 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”. The note also says the finished floor should be tested for certainty. So a plank or an underlay alone cannot hold a star rating.

Many test sheets still print a star line. Read it as the tester’s comparison of one measured result with the AAAC table. The Wonderwood sheet says it “is not an acoustical certification of the tested products”. If your by-law asks for a star certificate, look up the testing firm on the AAAC’s member firm list.

Is the figure on the spec sheet a lab or a field result?

Look at the symbol. Ln,w and ΔLw are laboratory figures. L’nT,w (also written LnT,w) is measured in a real building. The NCC Part F7 uses Ln,w for its laboratory rule and LnT,w for its on-site rule (62 or lower for both), and AAAC stars use the on-site figure. ΔLw is defined in AS ISO 717.2 as the improvement a covering gives on a standard bare heavy floor. So you cannot subtract a ΔLw from your own building’s figure.

Hybrid spec sheets use both kinds of figure. Signature Floors quotes a ΔLw of 19 dB and an Ln,w of 58 for its 6 mm hybrid (acoustic guide). LICO quotes about 17 dB of impact sound reduction to EN ISO 717-2 (data sheet). The Nouvelle Acoustic data sheet quotes an on-site L’nT,w of 39. Godfrey Hirst gives both: an on-site L’nT,w of 48, and a ΔLw of 19 dB calculated from the same site test (CodeMark certificate).

In a field test, a standard tapping machine drops five hammers 40 mm onto the floor, again and again. A microphone in the room below records the sound. This is described in a published Vipac field memo that tested two 6.5 mm hybrids with built-in underlay. They measured 48 and 49 on a 180 mm slab with no ceiling.

How do you read a hybrid acoustic test report?

A full report has several pages. The ABCB sound handbook (Appendix D.3.3) lists what a field report should state. This includes who tested and who paid for the test, the standards used, the test rooms, the positions of the tapping machine and microphones, and the frequency results. Koikas Acoustics adds a warning: its ratings “are indicative of a 1 m2 sample”, and a floor laid wall to wall “typically” rates up to 3 points worse (2023 report). Several reports also give slab and ceiling details as “estimated”, for example the Aspire report. The prediction tables from Godfrey Hirst and Signature Floors show why the slab and ceiling lines matter.

Acoustic hybrid brands: what each one publishes

These are the ranges people search for, and what each maker or seller published on its own site on 25 September 2026. It is not a ranking. A published report is more useful than a claim alone, but no report proves how a floor will perform in your building.

Sources for the table: Berkeley Acoustic from the Carpet Court range page (archived copy of 10 August 2025, because the live page blocked access on 25 September 2026) and its warranty. The “6 Star” row uses Wonderwood’s test sheet and Flooring Works’ range page. Nouvelle Acoustic uses the data sheet and installation instructions. LICO uses the data sheet, manual and LICO’s own article, which says its ranges “shouldn’t be classified as hybrid flooring”. Signature uses its acoustic guide and installation guidelines. Woodland uses its Highland, Australian Heritage and Acoustic Timber pages. Godfrey Hirst uses the CodeMark certificate and installation instructions. Preference uses the Iconic page, Iconic summary, Aspire report and installation guide.

What will a strata committee ask for with a hybrid floor?

Rules differ between buildings and states, so start with your by-laws and our guide to strata flooring rules. In NSW, installing hard flooring is a minor renovation that needs approval. NSW Fair Trading says that for flooring you should include “an acoustic certificate to show sound insulation” with your request.

Published NSW tribunal decisions show why a certificate is only the first step. In Jiang v Sui, a supplier’s certificate gave L’nT,w 44 (5 star) for laminate on a foam underlay. The owner’s own test after installation measured 51 and 54. The tribunal ordered the owner to reach at least 5 star or put carpet back, and then to arrange a test by a qualified acoustical consultant. In Kim, a floor approved “for a 5 star rating” measured 60 and 61 on site. The owner was ordered to treat it to 50. Both floors were laminate, not hybrid, but a hybrid approval uses the same kind of certificate.

In a post-installation test, a consultant puts a tapping machine on your new floor and measures the sound in the apartment below. So you need your neighbour to give access. In Jiang v Sui, the tribunal ordered the neighbours to allow access on 7 days’ written notice.

Before you order, ask the committee in writing:

• which figure applies (an L’nT,w number or a star level) and in which rooms
• whether you must supply a test report before approval, and a test after installation
• which test report they will accept for the plank you want.

Our strata flooring checker lists what to ask for in your state.

Which installation details change the acoustic result?

A floating floor is only as quiet as its edges. A 2014 Queensland field study found that poor installation at the perimeter is a common problem. A floor that touches a wall or skirting becomes a path for sound (Inter-noise 2014). Koikas Acoustics’ reports say the floor “must not make contact with any walls or joineries” (2023 report). The rules below come from the Nouvelle Acoustic instructions, Godfrey Hirst’s instructions and the Preference Floors guide.

• Leave the maker's perimeter gap at every wall, column and pipe: 10 to 12 mm for Nouvelle Acoustic, at least 10 mm for Godfrey Hirst, 8 to 10 mm for Preference Floors.
• Fix skirting and scotia to the wall, never to the floor.
• Do not fill the gap with silicone or caulk where the maker bans it. Godfrey Hirst, Australian Select Timbers and Preference Floors all do.
• Keep kitchen islands, cabinets and heavy fixed items off the floating floor. Cut the floor around them and leave a gap.
• Put expansion joints at doorways and wherever a room is larger than the maker's limit: 15 m by 12 m for Nouvelle Acoustic, 20 m by 15 m for Godfrey Hirst.
• Never glue, nail or screw a hybrid down. Do not lay it over carpet, a cushioned floor or another floating floor.
• Do not add a second underlay unless the maker approves that product in writing.
• Make the subfloor flat to the maker's tolerance. Godfrey Hirst says an uneven subfloor can make the floor sound drummy.

One difference to know: Koikas suggests filling the edge gap with a mastic-type sealant or an offcut of underlay (2023 report). Godfrey Hirst and Australian Select Timbers ban silicone and caulk in the gap (Godfrey Hirst, Nouvelle Acoustic). Follow your maker’s rule, because the maker’s rule decides the warranty.

How do you decide between the alternatives?

Compare a hybrid system with the actual alternative on your shortlist, rather than with a general description of timber or vinyl. Note the finished height, approved backing and test construction for both. Keep aesthetic preferences separate from claims that need a report.

Our comparisons cover hybrid vs laminate, hybrid vs vinyl and hybrid vs engineered timber.

How do you decide between the alternatives?

Compare a hybrid system with the actual alternative on your shortlist. Note the finished height, approved backing and test construction for both. Keep aesthetic preferences separate from claims that need a report.

Our comparisons cover hybrid vs laminate, hybrid vs vinyl and hybrid vs engineered timber.