If you’re researching a soundproofing project, you’ve likely come across the name Green Glue, a type of acoustic caulk. I often get people asking me about the benefits of Green Glue vs. regular caulk, so here’s a quick answer;
The main difference of Green Glue vs. regular caulk is that it’s primarily a sound dampening compound. Unlike regular caulk, Green Glue never truly hardens, and its flexibility allows it to stop vibrations from passing through a structure.
In this article, I’ll cover the important differences between Green Glue and regular caulk, including a comparison chart. Hopefully, by the end, you’ll understand exactly why Green Glue is so useful.
Also read: Green Glue vs. MLV
What is Green Glue?
Green Glue (Amazon link) is a brand name for acoustic caulk. As the term suggests, this is a specific type of caulk designed for use in soundproofing projects.
Read my review of Green Glue.
Acoustic caulk is a latex-polymer based type of caulk that has viscoelastic properties. In simple terms, this means it never fully dries.
Instead, it always retains some level of elasticity, even a long time after application. But why is this useful for soundproofing?
Green Glue helps to isolate parts of a structure because of its elasticity. It acts as a noise dampening compound that prevents vibrations from passing between rigid objects.
For example, in a standard wall setup you’d have the wall studs (made of wood or metal) with sheets of drywall attached.
These materials are all rigid, which means vibrations (sound waves) can pass through them quite easily.
When you add a layer of acoustic caulk, however, it helps to isolate one part of the structure from another. This might typically be between 2 sheets of drywall.
The product’s elasticity means that when sound waves make contact, they simply make it vibrate. But rather than passing the vibrations through the structure, Green Glue converts them into heat energy.
You could look at this as a form of absorption, but that has another meaning in the soundproofing world. It’s better to think of it as a lack of transfer.
Green Glue converts sound energy into heat because the sound waves cause the particles to vibrate. As it’s elastic, the particles just wobble around rather than transferring the energy. The sound waves then expend their energy trying to move the Green Glue, which they’re unable to do.
The results of using Green Glue are surprising and almost immediately noticeable. Lab tests have shown it can reduce sound transfer by up to 90% when used correctly.
When it comes to a soundproofing project, this really isn’t something you can pass up if you want best results.
Green Glue vs. Regular Caulk
So we know some information about Green Glue, but what about regular caulk?
Regular caulk is usually made of acrylic, but can also be latex or silicone. This will depend entirely on its purpose.
Importantly, though, regular caulk is designed mainly for thermal insulation and filling gaps. It doesn’t remain elastic because that’s generally not a useful property to have in these situations.
To make it easier, here’s a quick comparison chart:
|Green Glue||Regular Caulk|
|Main Ingredient||Latex polymer||Latex, acrylic, or silicone|
|Curing Time||30 days||1-10 days|
|Price||Mid-range||Cheap to mid-range|
|Lifespan||6-10 years||5 years|
|Adhesive||No||Yes, depending on ingredients|
As you can see, Green Glue is definitely the winner in soundproofing projects. Regular caulk definitely has its uses and benefits, but it’s not the right product to use if you want to reduce sound transmission.
If you’re considering using regular caulk because you don’t have the budget for a specialist product, I’d recommend just not bothering.
Green Glue might seem pricey, but it’s definitely worth the money. Also, buying in bulk, such as this 5 gallon bucket (Amazon link), will save you around 20% compared to buying individual tubes.
You would also need a dispensing gun (Amazon link), however.
When using Green Glue, there are a couple of things you need to be aware of first. These include:
1. Coverage area
A single tube of Green Glue provides 40-80 linear feet of coverage. The manufacturer recommends using 2 tubes per 4 x 8ft sheet of drywall.
A 5 gallon bucket covers roughly 365 square feet at the correct density and spread.
Bear these figures in mind when working out how much of the product you’ll need to buy.
2. Applicable materials
Remember, Green Glue isn’t an adhesive – you can’t use it for sticking things together. You’d still need to fix 2 sheets of drywall together with screws, nails, or normal glue if using acoustic caulk.
It should only be used on porous, rigid materials, such as:
- Cement board
Avoid using it on things like plastic and material, as it won’t work well.
3. Material thickness
You may already know that mass is an important factor in soundproofing. Therefore, I recommend using the thickest drywall you can find. This would typically be 5/8”.
4. Curing time
Technically, Green Glue never completely cures. This is one of its major differences to regular caulk, which can become dry and crumbly over time.
Green Glue will begin curing within 15 minutes of application, but won’t be considered “fully cured” until 30 days have passed. Factor this into your project timeline.
5. Other soundproofing materials
Green Glue is best when used alongside other soundproofing materials, such as mass loaded vinyl (Amazon link).
However, you can’t apply Green Glue directly to MLV because it’s neither rigid nor porous. Instead, fix the MLV to one piece of drywall and fix this to another sheet with Green Glue in between.
How to Apply Green Glue
Another major area of difference when it comes to Green Glue vs. regular caulk is the application method. Of course, this is because they perform different jobs, but also because you use them in different areas.
Here’s a rundown of exactly how to apply Green Glue in your soundproofing project.
1. Get ready
The first step is to clean the room. Make sure the walls are clean and dry and that the space is well ventilated. It’s a non-toxic, low-odor product, but it’s worth taking this step.
Also, ensure you wear a mask and other safety equipment.
2. Gather your equipment
Along with the drywall that’s probably already hung, you’ll need another sheet (that you’re going to fix up).
Also, you’ll need your Green Glue and applicator, and some screws for security. Remember, Green Glue isn’t an adhesive!
3. Get your tubes ready
You should already know how much Green Glue you need for the space, so get these ready.
Prepare your first one by cutting the tip off the nozzle. If you’re using the bucket and applicator, you can skip this step.
4. Apply the product to the drywall
Simply squeeze the Green Glue over the drywall in a random pattern. Ensure it’s thick enough, as per the instructions. Also, it might help to leave a 2-3” gap around the edges for easier handling.
This will also compensate for any spread when you apply the other sheet of drywall. You can always go in and apply more once it’s hung.
5. Fix the layer of drywall
Now you’ll need to put up the outer layer of drywall by fixing it to the studs. It’s important to follow your local building codes, if applicable, and that the drywall is fixed in place securely.
You shouldn’t need anything more extensive than some screws because drywall itself isn’t heavy.
6. Touch up any areas
If you notice any gaps that might present issues, apply a bit more Green Glue. You don’t need to plug every single gap because it’s not really a sealant, but the better layer you have between the drywall, the more effective it’ll be.
7. Let it cure
You’ll need to wait 30 days before you get the true results. I’d recommend leaving it around 48 hours before you start decorating just to ensure the Green Glue is dry enough that it won’t affect your paint.
8. Treating the rest of the room
Although not technically a sealant, you could also use Green Glue to plug any gaps you might have noticed around the room. These could include:
- Around door frames
- Around windows
- Around HVAC vents
The application process for these jobs is much the same as using regular caulk: you’re simply applying it to fill a small gap. Squeeze it in and wipe away any excess.
In fact, check out this video for how to apply caulk to a crack for some useful tips.
Some Final Thoughts
Hopefully, this article has covered some of the most important points for Green Glue vs. regular caulk.
In short, it boils down to Green Glue being designed for soundproofing projects rather than thermal insulation.
I recommend using it in your next project because the results are quite impressive.
That said, make sure you do plenty of research about your project to ensure it’s going to be the right product for your needs.