Description
How Mass Loaded Vinyl Blocks Sound
There are two different jobs in acoustics and they need opposite materials. Absorption soaks up sound already loose in a room and shortens echo. Blocking stops sound getting from one room into the next. Mass loaded vinyl does the second job, and nothing soft and fluffy will do it for you – if a material is light enough to let air through, it is light enough to let sound through.
Sound crossing a wall does it by moving the wall. Push a partition with a sound wave and it flexes, and that flexing radiates the sound out the far side. Two things stop that:
- Mass. A heavier layer moves less for the same push. This is why a concrete wall is quiet and a hollow door is not, and it is the whole principle behind a mass loaded vinyl sound barrier.
- Limpness. Drywall is stiff, so it has resonant frequencies where it flexes easily and leaks sound badly. MLV is vinyl loaded with dense mineral filler – heavy, but floppy. It has no resonance to speak of, so it has no weak frequencies for sound to slip through.
That combination is why 1/8″ of MLV at 1 lb per square foot outperforms materials many times its thickness. You are not trying to trap the sound; you are trying to make the wall too heavy and too dead to pass it on.
What STC 26 Means for MLV Soundproofing
STC – Sound Transmission Class – is a single number for how much sound an assembly stops. Higher is better, and every 10 points is roughly a halving of perceived loudness.
STC 26 is the rating of the MLV sheet on its own. That number on its own is not what you buy it for, because you never install it on its own. What matters is what it does to the wall you add it to:
- A single layer adds 10+ STC points to a wood- or metal-frame assembly – effectively doubling its soundproofing performance.
- A single stud wall with one layer of mass loaded vinyl and one layer of drywall each side reaches STC 56+, comfortably above code for multi-family and hospitality work.
- It does the work of 3 to 4 layers of drywall for a fraction of the cost, and adds 1/8″ instead of several inches.
That last point is usually the deciding one. Stacking drywall is the other way to add mass, but every layer costs money, eats room dimension, loads the framing and has to be taped and finished. One layer of MLV goes up in an afternoon.
Where a Mass Loaded Vinyl Sound Barrier Works Best
Anywhere sound is getting through a structure rather than bouncing around inside one:
- Party walls in apartments, condos, hotels and student housing – the application the STC 56+ assembly above was built for.
- Home theaters and studios – keep the low end in the room and the rest of the house out of the recording.
- Between floors – footsteps and voices from the unit above. Pair it with AcoustiStep underlayment where impact noise is the problem rather than airborne.
- Mechanical rooms and equipment enclosures – MLV is flexible enough to be wrapped around or molded to the shape of the thing making the noise, which rigid barriers cannot do.
- Ductwork and pipes – wrapping a noisy run is one of the highest-value uses of a roll. See the Pipe Blokker for a purpose-made version.
- Ceilings and floors, not just walls – see Ceiling Blokker and Floor Blokker.
Tell us the assembly and what you are trying to keep out and we will tell you whether MLV is the right answer for it.
How to Install Mass Loaded Vinyl Rolls
Mass loaded vinyl rolls are 4′ wide and 1/8″ thick. A 4′ x 25′ roll covers 100 square feet and weighs about 100 lb, so plan on two people and a sharp utility knife.
- Fix it to the framing – staple or screw it straight to wood or metal studs. Over existing drywall works too, and saves tearing a finished room apart.
- Seal every seam. This is the step people skip and it is the step that decides the result – a gap passes sound as if the barrier were not there at all. Overlap the edges and seal them with MLV seam seal tape, and caulk the perimeter with acoustical caulk.
- Then cover it. A new layer of drywall goes over the top and gets finished normally. The MLV disappears into the wall.
- Do not forget the holes. Outlets, switches and penetrations leak – an Outlet Blokker handles the boxes.
- Worked example: a wall 12’6″ long by 8′ high is 100 square feet, so it takes exactly one roll – two courses of 4′ plus a trimmed strip. Add roughly 10% on longer runs for seam overlap.
For Commercial Pricing on Mass Loaded Vinyl, contact Commercial Acoustics.
Frequently Asked Questions
- What is mass loaded vinyl?
- A thin, heavy, flexible sheet – vinyl loaded with dense mineral filler – installed inside a wall, floor or ceiling to stop sound passing through it. Ours is 1/8″ thick and weighs 1 lb per square foot, supplied in 4′ x 25′ rolls. It is sold as MLV, mass loaded vinyl and mass loaded vinyl sound barrier; they are all the same product.
- What does STC 26 mean?
- Sound Transmission Class is how much sound an assembly blocks, and every 10 points is roughly a halving of perceived loudness. STC 26 is the rating of the MLV sheet by itself. In use it is the assembly that counts: one layer added to a wood- or metal-frame wall lifts it 10+ STC points, and a single stud wall with MLV and a layer of drywall each side reaches STC 56+.
- How much mass loaded vinyl do I need?
- Measure the surface you are treating in square feet – one 4′ x 25′ roll covers 100. An 8′ high wall 12’6″ long is exactly one roll. Add about 10% on longer runs so seams can overlap, and treat the whole surface: a wall that is 90% covered performs like the 10%, not the 90%.
- Does MLV go over or under drywall?
- Either works. Fixed to the studs with drywall over it is the tidiest and what most new work does. Over existing drywall, with a fresh layer on top, gets you the same mass without stripping a finished room back to the framing.
- Is mass loaded vinyl sound deadening or soundproofing?
- Both terms get used for it, and in everyday search they mean the same thing. Strictly, MLV blocks airborne sound transmission and damps vibration in the surface it is fixed to. What it does not do is quieten a room you are standing in – that is absorption, and it is a different product.
- Is this the same as AudioSeal or Soundsulate MLV?
- Mass loaded vinyl is a material, not a brand. AudioSeal is Acoustical Solutions’ MLV and Soundsulate is another company’s; ours is the same class of product. What actually separates one roll from another is the numbers — weight per square foot, thickness and STC — because the mass is what does the blocking. Ours is 1 lb/sf, 1/8″ thick, STC 26, in 4′ x 25′ rolls. Compare on those three and you are comparing the thing that matters.
- Which Wall Blokker should I buy instead?
- Wall Blokker is our branded mass loaded vinyl, in three weights, all as a 4′ x 25′ roll. Wall Blokker Lite – STC 21 min, 0.6 lb/sf, 1/16″ – is for metal studs, where the framing already flexes. Wall Blokker – STC 26 min, 1 lb/sf, 1/8″ – suits metal or wood and is the default. Wall Blokker Pro – STC 26 plus scrim, 1.1 lb/sf, 3/16″ – adds a fused polyethylene scrim worth 3 to 5 STC points, for wood studs, party walls and retrofits over existing drywall.
- Can mass loaded vinyl be used on floors and ceilings?
- Yes. The material is the same; only the fixing changes. Under flooring it is usually paired with an underlayment for impact noise, and overhead it goes above the ceiling finish. Floor Blokker and Ceiling Blokker are the assemblies built around it.
- Will mass loaded vinyl stop echo in a room?
- No, and this is the most common mix-up in soundproofing. MLV stops sound leaving or entering a room; it does nothing for the echo bouncing around inside one, because it is not absorptive. For that you want sound absorbing wall panels or acoustic ceiling clouds. Plenty of rooms need both.
STC 26 · 1 lb/sf · 1/8" Thick
Chelsi Jong –
my client asked that i use the vinyl sound barrier they sell here. We ordered it and got it 3 days later – really pleased with the quality. Truck had a lift gate to help us get it down or i wouldve needed 2-3 guys to help unload the pallet. installed on ceiling/walls/floors – it was quiet before we even put the drywall on! super pleased with customer support and product.
Kim Salling –
We installed this product on metal studs with excellent results! Had a consultant come and test afterward with good stc
Roger Stanley –
The Mass Loaded vinyl is really heavy stuff. It seemed to do the job on our walls well though. We had our contractor put it into the movie studio/theater and the master bed wall, and both of them are really quiet for us now…
Gene upshaw –
we use this in our walls now when we build new. Works fine – good price.
Raj Gupta –
I wanted to calculate the estimated price of soundproofing for walls, ceiling, and fooring, Could you please advise?, how much pressure-sensitive adhesives consumed in MLV sound barrier. What will be the cost of adhesives?
Walter Peek –
In most cases, you should budget an additional $2-$3/sf for soundproofing with Mass Loaded Vinyl. This allows for PSAs (Pressure Sensitive Adhesives) along with labor and material for installing the MLV.
Gordo –
I am looking to use this as a temporary sound proofing measure for a vocal booth in an apartment; however, the reviews here sound like it comes in a quantity that exceeds both my needs and ability to carry into my apartment (one reviewer mentioned needing a truck lift gate and multiple men to lift the pallet). Is my impression accurate? If so, are there any other size/quantity options?
Rachel –
Hi Gordo,
Yes, this material weighs 1 lb/sf and only comes in 4’x25′ rolls weighing 100 lbs total. Unfortunately, we don’t sell this in any other sizes, but the material is easily cut using a utility knife or razor blade, so you could cut the roll into sheets prior to carry it inside.