Acoustic Batts: Which One for Walls, Partitions, Floors and Ceilings

Pick the acoustic batt by the building element, then by density, because density is the acoustic specification and R-value is not. A 90 mm internal stud wall takes R2.5 SoundScreen at 88 mm or R2.7 Soundbreak at 90. A steel framed commercial partition takes Pink Partition or Acoustigard at the grade the system names, 11, 14, 22, 24 or 32 kg/m³. A timber floor takes the 140 mm polyester blanket.

This page is about which product, not why. Density rather than R-value, what an Rw belongs to and flanking are in acoustic insulation versus thermal insulation. What follows is the published figures, side by side.

Start with the building element

Most wrong orders start with the word "acoustic" rather than the element being built. The element narrows it to one or two products before a number is read.

A party wall is a fire separation as well. R2.7 Pink Soundbreak is the catalogue batt for that work and the rest sits in insulation in party walls and apartments.

What the data sheets publish

Two measurements are worth reading off an acoustic data sheet and neither appears on a product title. NRC averages absorption coefficients across the bands, tested to AS/ISO 354 and rated to ASTM C423. Flow resistivity, in Rayl per metre to ASTM C522, tracks density far more closely.

Bradford publish no kg/m³ for SoundScreen and Fletcher publish a range for Soundbreak, so flow resistivity is the stand in for both. Acoustigard reaches R2.5 in two grades, which acoustic insulation versus thermal insulation works through; the figure that article does not carry is the flow resistivity, 4,173 against 10,600 Rayl/m at an NRC within 0.05. At 14 kg/m³ and 50 mm Bradford declare 9,680 Rayl/m against Fletcher's 4,040, both to ASTM C522 but by different laboratories, so a spec naming a density has not named a brand.

Internal walls in a house

Internal walls are framed at 90 mm most of the time, which is why R2.5 SoundScreen at 88 mm carries most residential acoustic work, at NRC 1.10 and 14,130 Rayl/m. Fletcher's answer at that depth is R2.7 Pink Soundbreak at 90 mm, dyed green so it can be identified once it is in the wall, at NRC 1.1 and 16,001 Rayl/m. At 70 mm the two land almost on top of each other, 12,760 against 12,860, and at 110 mm they separate, 15,460 against 12,760.

Bradford state that R2.0, R2.5 and R3.1 SoundScreen will not compress, and that forcing one into a shallow cavity risks deforming or detaching the rigid lining. Width follows the framing, 430 to 450 mm centres and 580 to 600 mm, which is general Australian building practice rather than a manufacturer specification. One correction we owe the reader: our R2.0 Pink Soundbreak variants read 75 mm where the Fletcher sheet lists 70 mm nominal, so build to 70 mm.

Commercial partitions and pack counts

On a steel framed partition the number in the product name is the density in kg/m³, and that is what a tested system quotes. Pink Partition comes in 11, 14, 22, 24 and 32, friction fitted to metal framing, mostly 1200 mm long in 450 and 600 mm widths with seven lines at 2700 mm. Acoustigard covers the same ground in rolls at 11, 14 and 24, plus one batt at 14 kg/m³.

• The 24 grade starts at 25 mm, at R0.65, NRC 0.65 and 14,400 Rayl/m, the thinnest section in Bradford's Acoustigard table. Fletcher have a 25 mm line too, Pink Partition 24 at R0.7, at 600 x 2700 mm.
• Dense grades will not compress. Bradford give that warning for Acoustigard 24 and 32, Fletcher for Pink Partition 22, 24 and 32.
• Acoustigard coverage is per pack, not per roll. A 13.5 m x 600 mm listing at 16.2 m² is two rolls.

Fletcher list the Pink Partition range for partition walls in multi-residential buildings and commercial fit-outs including offices, schools and shopping centres, so which grade a job needs comes from the system report rather than from us. Pink Partition 32 is the densest glasswool we carry, 20,840 Rayl/m at 50 mm, and Fletcher hold CodeMark CM 30006 on the range with indices of 0, 0, 0, 1 and BAL Low to Flame Zone. The 22 kg grade is an order in line for us rather than a stocked one, and our own 32 kg listings carry the 24 kg coverage figures by mistake, so order that grade off the sheet.

Same wall, same batt size, 2.7 times as many packs at 50 mm when the spec moves from 11 to 24 kg/m³. That is why a substitution to a lighter grade keeps getting proposed. A substitution that has to survive a superintendent needs the grade, the density and the document named in the package, which is the ground of specifying insulation for a tender.

Timber floors and midfloors

The floor product is the R2.5 Martini Polyester Acoustic Floor Blanket, a 10 m roll 430 mm wide and 140 mm thick covering 8.6 m², CSR code 127824. It rolls out along a joist bay instead of being cut batt by batt. What it does not come with is data: no manufacturer sheet is attached, so we hold no density, NRC, flow resistivity or fire index for it. The R2.5 is declared to AS/NZS 4859.1.

A floor is usually specified on impact sound, Ln,w or L'nT,w, and none of the manufacturer documents behind this article publishes an impact figure. That belongs to the whole build up tested together: flooring, underlay, joists, insulation and the ceiling below. For a midfloor in a house, Fletcher name midfloors among the uses for R2.7 Pink Soundbreak.

Ceilings and plenums

A ceiling batt does the same work in the joists that it does in a wall, and Bradford document SoundScreen for wall, floor and ceiling. The other ceiling job is the void above it.

Flanking over the top of a partition is covered in acoustic insulation versus thermal insulation. The product for it is the Martini Polyester Easy Baffle, 1200 x 600 x 100 mm, eight to a pack for 5.76 m², CSR code 129188, at NRC 0.85 to AS/ISO 354. Laid flat above a suspended ceiling instead, the product is Martini Polyester MAB, 11 to 60 kg/m³ and 25 to 100 mm, as 610 mm rolls and 2400 x 1200 mm sheets. MAB publishes no absorption coefficients, no NRC and no flow resistivity, so a report naming an NRC cannot be matched to it from CSR's own document.

Mass barriers

Wavebar and Quadzero are mass loaded vinyl, so they block rather than absorb. They look interchangeable on a shelf. On the documents they are not.

Read the Rw row with the row beneath it. The figures are identical because the testing was done on Wavebar, and Pyrotek say so in a footnote under their own Quadzero table. Quadzero earns its place on the fire and facing rows, and even its Group 3 result carries an asterisk naming the black foil version while the product we stock is silver. Wavebar runs 2 to 10 kg/m² at Rw 21, 25, 28, 31 and 34, so doubling from 4 to 8 buys 6 Rw points.

Which coverage number to order on

Bradford print two coverage figures for the same pack, and so does Fletcher on the Soundbreak sheet. One is the batt area, the pieces multiplied out. The other allows for the framing the batts sit between, and Bradford's assumes a single batt between 35 mm joist framing. The Pink Partition sheet prints one figure only.

Estimate on the smaller figure, the one our product pages carry. On the 1200 mm SoundScreen sizes for steel frame the two match, because there is no timber to allow for. Quote the code as well. Bradford are moving the whole SoundScreen range to SoundScreen Comfort Touch Technology from May 2026 and every line gets a new one: R2.0 becomes 493921, 493922, 493934 and 493935, R2.5 at 88 mm becomes 493930, 493931, 493936 and 493937, and R3.1 becomes 493932 and 493933. The 1200 mm R3.1 sizes, 490101 and 487764, go at the same date.

Frequently asked questions

Sources

Product selection information, current at September 2026. It does not decide compliance. An Rw, an Ln,w or a Group number belongs to a tested system and to the project's acoustic report, so the consultant and the surveyor take priority. Where our catalogue and a manufacturer document disagree, this page follows the manufacturer. Codes and pack sizes change, so confirm the current sheet before ordering.