Green Glue vs. MLV – Which is Better for Soundproofing?
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When researching soundproofing products, you’ve likely come across both Green Glue and MLV (mass loaded vinyl). If you’ve wondered which is better, Green Glue vs. MLV, here’s a quick answer:
In terms of performance for Green Glue vs. MLV, there isn’t really a competition, as both do different things. MLV is used for blocking sound by adding limp mass to a structure, while Green Glue is used for dampening sounds and reducing vibrations. You should really use both in a project.
To understand why these 2 products don’t really compete with each other, it’s first necessary to understand what they actually do. Here are some quick definitions of each product.
Also read: Is Green Glue Worth It For Soundproofing?
What is Green Glue?
Green Glue is a viscoelastic compound, similar to caulk. It’s used for dampening vibrations before they become sound waves.
It does this by never fully drying, meaning it retains a level of elasticity even after it’s fully cured. In turn, it prevents vibrations from passing through a structure because they can’t make the product vibrate.
Much like acoustic foam, Green Glue converts sound waves into heat energy. This happens because the sound waves make contact with the product and expend their energy trying to make it vibrate.
As energy can’t be destroyed, it’s converted into heat energy instead.
In a soundproofing project, you should use plenty of Green Glue on surfaces to reduce the level of sound transfer through a structure. It does this pretty well, which is why it’s a popular choice.
What is Mass Loaded Vinyl?
MLV is a thin material made from vinyl. It’s very flexible, but it’s also very dense and limp. MLV is what’s known as limp mass, which you can understand in more detail by watching this video.
In short, limp mass doesn’t vibrate when sound waves make contact with it. This essentially blocks sound waves from passing through a structure.
Also, MLV simply helps to add more mass to a structure. This is a benefit because the more mass a structure has the less it can vibrate anyway.
So, MLV is helpful for 2 reasons. It’s a popular choice for soundproofing walls, floors, and ceilings, and comes in several weights.
MLV’s mass is measured in pounds per square foot. Generally, you’ll find 0.75lbs, 1lb, and 2lb versions.
Obviously, the greater the mass the more it’ll prevent a surface from vibrating.
As you can see, it’s not really possible to compare MLV and Green Glue because they both perform different functions within soundproofing.
MLV adds mass while Green Glue dampens vibrations. They both cover different aspects of the key principles of soundproofing.
The STC of Green Glue and MLV
Perhaps the only way to really compare the 2 products is to understand their sound transmission class (STC).
STC is defined as how well a structure isolates sound. The higher the number, the better the structure isolates sound.
For example, a normal stud wall with 2 sides of 5/8” thick drywall will have an STC of around 40-45, depending on other factors.
Adding a layer of MLV into the wall can improve its STC to around 50.
However, adding in 2 tubes of Green Glue between 2 sheets of drywall, on each side, can raise the STC to around 55.
I think it’s fair to say that both products have a similar STC, as the Green Glue includes 2 extra layers of drywall. But using them both together will result in an STC of around 60, which is much better.
Of course, for best results, I’d always recommend using both MLV and Green Glue as part of a number of other methods.
Green Glue vs. MLV – Which is Better?
When it comes to deciding on the performance of both products, it’s worth considering more than their STC.
For example, I also recommend considering things like price, ease of application, and the frequencies of sound they work against.
Here’s a list of my pros and cons of both products to make it clearer.
Pros of Green Glue
Easy to apply
Green Glue is pretty easy to apply. It either comes in a tube or a bucket. If you choose the second option, you’ll need a dispensing gun (Amazon link).
To apply it, you just need to squeeze it all over a surface. I recommend using 2 tubes per 16 square feet for the best results.
Works against low frequencies
Many soundproofing products are most effective against high and medium frequency sounds. After all, this is what you’ll primarily be working against if blocking out sounds like TV, music, and voices.
But Green Glue is great against low frequency sounds too. This makes it a useful addition to soundproofing projects because it fills in for weaker areas.
Useful for blocking gaps
Sound works much like heat: it can escape from event he smallest gaps. As Green Glue is applied as a liquid, it’s ideal for fitting into really small gaps.
Cons of Green Glue
It takes a while to cure
Green Glue takes around 30 days to fully cure, meaning you won’t get the best results until then.
While this isn’t a massive issue, it’s worth bearing in mind when planning your project timeline.
It’s quite pricey
Green Glue isn’t cheap. But if you buy in bulk, such as this 5 gallon bucket (Amazon link), you can save around 20%.
Pros of MLV
Easy to apply
For the most part, MLV is pretty easy to apply. It can be very heavy when working with the whole roll, but it’s fine when cut into smaller pieces.
The easiest way to work with it is to buy a large roll of MLV (Amazon link) and then fix it to a sheet of drywall.
You can then put this drywall up as usual (sealing everything with Green Glue of course).
Performs well in most conditions
The benefit of MLV is that it performs really well in almost all conditions. This is because it’s a pretty simple product: it’s just a heavy material.
Providing you’re able to apply it properly to a surface, you should notice a great reduction in sound transmission almost immediately.
It’s not too expensive
Considering it’s a specialist product, MLV isn’t too expensive. Bear in mind that you’ll have to pay more for the heavier versions.
Cons of MLV
Can tear quite easily
MLV can tear fairly easily if not supported properly during and after installation. This is mainly due to its weight.
To fix this issue, you just need to hold it in place with some screws and washers spaced evenly across the product. Every foot or 2 should be fine.
Off-gassing
MLV smells when you first unpack it. To overcome this, unpack it well ahead of time and give it a while to air out before you start the installation.
Some Final Thoughts
When it comes to Green Glue vs. MLV, I wouldn’t consider it to be an either/or situation.
I’d recommend using both as part of your soundproofing project because they offer different benefits.
Hopefully, this article has explained why and has put you in a good position for creating a fully soundproof space.
