IAC AcousticsThailand · since 2009

What is mass loaded vinyl (MLV), and when is it the wrong material

Updated 2026-08-15

The short answer

Mass loaded vinyl (MLV) is a limp, high-density sheet used to add mass to lightweight construction so less sound passes through it. BlastBlock BB830, supplied in Thailand by IAC Acoustics (Thailand), is nominally 5 kg/m² at about 3 mm. It blocks sound transmission; it is not acoustic foam, which only reduces reverberation within a room.

What mass loaded vinyl is

Mass loaded vinyl is a flexible sheet in which a mineral filler is loaded into a vinyl carrier to raise its density. The result stays limp and rollable, which matters acoustically, but weighs several times what a sheet of the same thickness would otherwise weigh. It is a barrier material: its job is to stop airborne sound passing from one space to another.

BlastBlock BB830, the grade held in stock in Bangkok, is nominally 5 kg/m² at about 3 mm. Quote the mass first and the thickness second. Mass is what blocks sound; thickness is packaging, and a buyer comparing 3 mm against 3 mm without looking at areal density is comparing the wrong number. A full 5 m² roll weighs about 25 kg.

The mass law, and why density is the number that matters

Sound transmission through a single limp panel is governed by the mass law: every doubling of mass per unit area buys roughly 6 dB more transmission loss, and transmission loss also rises with frequency at about the same rate per octave. Two consequences follow, and both are practical.

  • Low frequencies are the hard part. Bass and machinery hum pass through a wall far more easily than speech, which is why a neighbour’s conversation becomes a mumble long before their subwoofer does.
  • Doubling matters, not adding. Going from 5 kg/m² to 6 kg/m² is worth about 1.6 dB, which is close to inaudible. Real gains come from decoupling and cavity depth once mass alone runs out.

Transmission loss by frequency for BB830, according to the manufacturer’s datasheet, reference BB830/20/v2. These are laboratory values for the material alone; field performance in a finished wall is normally lower.

BlastBlock BB830 transmission loss in dB, manufacturer data, laboratory values
Frequency (Hz)BB830 at 1 mmBB830 at 3 mm
125516
250925
5001534
10002136
20002634
40003445

MLV is not acoustic foam

This is the most common and the most expensive confusion in the subject, and it costs people money every week. Acoustics has two entirely separate problems. Blocking sound stops it travelling from one room to another. Absorbing sound reduces reverberation within a single room. The materials are different, the units are different, and neither substitutes for the other.

Barrier materials and absorptive materials do different jobs
AspectBarrier (MLV)Absorber (foam, mineral wool facing)
PurposeReduce sound reaching the next roomReduce echo within the same room
MechanismMass and densityPorosity and air friction
Measured bySTC, Rw, transmission lossNRC, absorption coefficient α
Where it goesInside the wall, floor or ceiling build-upOn the exposed room surfaces
Fixes a noisy neighbourYes, if the wall is the pathNo

Where MLV is the wrong answer

MLV is oversold, and specifying it into the wrong problem wastes the budget that would have fixed it. These are the cases where we will tell you not to buy it.

  • The wall is already heavy. A 150 mm concrete or dense masonry wall carries 250 to 400 kg/m². Adding 5 kg/m² to that is a rounding error. Spend the money on the door, the windows and the penetrations instead.
  • The problem is footfall from the floor above. Impact noise travels through the structure. Mass on a wall does nothing for it, and mass on a ceiling helps only as part of an isolated, resiliently hung build-up. Treating the source floor is usually cheaper and works better.
  • The problem is echo, harshness or poor speech intelligibility inside one room. That is absorption, not a barrier.
  • The dominant path is a door, a window, an air-conditioning penetration or a duct. Fix the path that is actually carrying the sound before you add mass to the surface next to it.
  • You cannot get access to seal the perimeter. An MLV layer that cannot be sealed at its edges will not deliver a result worth paying for.
  • The target is very low frequency, below roughly 125 Hz. Mass alone is weak there. Cavity depth, decoupling and a double-leaf construction do the work; MLV contributes but will not carry the job on its own.

What STC the material carries, and what that does not tell you

The material alone is STC 32 at 3 mm and STC 19 at 1 mm, according to the manufacturer’s datasheet, reference BB830/20/v2. Both are laboratory values. Treat them as a way of comparing barrier materials against each other, not as a prediction of what a finished wall will achieve.

STC is a property of an assembly, not of a material. The same 3 mm sheet inside a single-stud partition and inside a double-stud partition with mineral wool produces very different results, because most of the performance comes from the construction around it. A double-stud assembly with mineral wool reaches up to STC 68 according to the manufacturer.

The grades, and what has to be bought with them

BlastBlock grades held in stock in Bangkok. THB including 7% VAT, excluding VAT in brackets
ItemUsePrice
BB830Standard grade, nominally 5 kg/m² at about 3 mm1,122 /m² (1,049)
BB830FRWhere a fire requirement applies1,288 /m² (1,204)
BB830LFFormulated for low-frequency work1,761 /m² (1,646)
BA890 sealantSealing perimeters, joints and penetrations321 /cartridge (300)
BA990 adhesiveBonding the sheet to concrete, steel, timber or plasterboard428 /cartridge (400)
BA650 putty padBacking socket and switch boxes385 /pad (360)

MLV is sold in whole 5 m² rolls only. A sheet without sealant is an incomplete system, and the sealant is the part that decides whether the rest of the spend was worth making.

Fire performance

BB830FR has been tested by an independent third party. Under AS/NZS 1530.3:1999, SGS report AJFTS26000525R01_EN dated 3 February 2026, it returned indices of 0/0/0/7 for ignitability, spread of flame, heat evolved and smoke developed, and none of the six specimens ignited. That is a laboratory result issued by a testing house, and it is the one figure on this site that does not depend on the manufacturer.

Who makes it

The compound is engineered in the Netherlands and manufactured in Asia. BlastBlock is a brand of BlastBlock BV, the Netherlands, which owns the trademark and the product specification. IAC Acoustics (Thailand) Co., Ltd. is the reseller of BlastBlock in Thailand. We are currently the only BlastBlock supplier in Southeast Asia. It is ordered from here or not at all, and stock is held in Bangkok.

The exact formulation is proprietary and is not disclosed, as with any specialist compound. What is published in full, without a registration form, is the datasheet and the independent fire test report, which is what a specifier can actually use.

Buying in Thailand

Stock is held in Bangkok and dispatched within one working day of cleared payment. Delivery is free nationwide on orders over THB 20,000 excluding VAT; below that it is THB 500 to Bangkok and the surrounding provinces and THB 900 upcountry. Delivery is within Thailand only.

Frequently asked questions

How thick is mass loaded vinyl?
The standard grade, BlastBlock BB830, is nominally 5 kg/m² at about 3 mm. Mass is the figure that matters; thickness is a consequence of it. A 1 mm grade exists for weight-critical work, but its transmission loss is far lower — STC 19 against STC 32, according to the manufacturer.
What is the difference between MLV and acoustic foam?
MLV is a barrier: it adds mass so that less sound passes through a wall. Foam is an absorber: it reduces reverberation inside a room. They are not interchangeable. If the problem is a neighbour, foam will not help.
How many decibels will MLV give me?
There is no single number, because the result belongs to the whole assembly and to the quality of sealing, not to the sheet. Published figures are laboratory values and field performance is normally 5 to 10 dB lower. Ask for an assessment against your actual construction.
Does MLV stop bass from a neighbour’s sound system?
Partly, and less than people expect. Mass is weakest at low frequency, so a 3 mm sheet on its own will not solve a subwoofer through a party wall. That case needs cavity depth, decoupling and mineral wool, with mass as one component of the build-up.
Is MLV fire rated?
BB830FR was tested by an independent third party to AS/NZS 1530.3:1999, SGS report AJFTS26000525R01_EN of 3 February 2026, returning indices 0/0/0/7 with none of the six specimens igniting. The standard BB830 grade carries manufacturer flammability data only; specify BB830FR where a fire requirement applies.
What is the minimum order?
MLV is sold in whole 5 m² rolls. A pre-cut 1 m² trial piece is available if you want to test a fixing detail before committing to a project quantity.

Related

Want this checked against your own project?

Send the construction build-up and a description of the noise, and we will tell you where the material helps and where it does not. Stock is held in Bangkok and dispatched within one working day of cleared payment. Delivery is within Thailand only.

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