Acoustic Sealant for Soundproofing: Pros & Cons

Acoustic sealant being applied to plasterboard

Last updated: July 26, 2021 at 9:31 am

Acoustic sealant is essentially sealant which offers soundproof qualities. Using this type of sealant can add extra sound dampening to rooms, especially when using it along with acoustic plasterboard.

But does it really make a big difference or is it negligible?

In this article, we take a look at the pros/cons of acoustic sealant, which type is the best, and if there are any alternatives you could be using instead.

What Is Acoustic Sealant?

Acoustic sealant is a type of caulking very similar to the kind used in bathrooms and around windows. The difference is that acoustic sealant is specifically designed to block sound waves and convert them into heat.

It works in an identical way to green glue soundproofing compound, but their formulations are slightly different. Green glue is meant to be used on a large scale and is a soundproofing solution on its own; acoustic sealant is not.

How Is It Different to Normal Sealant?

The main difference is that it doesn’t dry out and so it remains flexible. If you’ve ever used regular sealant that been applied for a while, you’ll notice it’s gone hard and dried out. That would leave a gap that sound could slip through, so acoustic sealant is designed not to do this.

The other difference is that you can paint acoustic sealant, whereas you can’t do this with the standard variety.

Rockwool Acoustic Intumescent Sealant 310ml
  • Acoustic Intumescent Sealant 310ml

Last update on 2021-09-20 at 14:53 / Images from Amazon Product Advertising API

Advantages of Acoustic Sealant

Blocks Sound

Let’s start with the obvious one; it blocks sound. Similar to green glue, acoustic sealant will block sound waves and convert it into heat. By completing your soundproofing project by ensuring all remaining gaps are filled with acoustic sealant, you’ll notice a marked reduction in the amount of noise that gets in or out. Some experts estimate that you can reduce the noise penetration by 15% by using a proper sealant.

Doesn’t Shrink

Because you’re trying to plug all gaps and the sealant shrinks, you may as well not bother. Acoustic sealant has a formula designed not to shrink. So, if you sealed one window with acoustic sealant and one with regular and compared them in a few years, you’d notice the acoustic sealant looked almost completely unchanged. The normal caulk, however, would be shrunken and letting air and sound through.

Easy to Apply

Other soundproofing products are available, but what makes acoustic sealant useful is that it comes in a tube and applied with a gun through a thin nozzle. This means that it’s easy to apply with precision exactly where you want it. You should also find it simple to slide the nozzle into tight spaces where you’d struggle to fit a trowel or other application method.

Apply It to Almost Any Surface

Unlike regular caulking, you can apply acoustic sealant to a variety of surfaces, including wood, metal, plasterboard, and concrete. As a result, it’s very versatile, which means you don’t need to go to the expense of buying a range of different products depending on the area you want to seal.

Some Brands Are Weather Resistant

When combined with the previous point, this means you can use it anywhere. So if you’re soundproofing a room and there are gaps around the window frame outside, you can use it here too. It will adhere to the brick and the frame and form a tight seal. It will achieve its primary purpose of blocking sound, but it will also help keep in the heat and stop water from getting in.

Non-Flammable, Non-Toxic, and Water-Based

It’s understandable to be wary of the products we add to our homes, but acoustic sealant is pretty safe. Being non-flammable, there’s no increased fire risk. It’s non-toxic, so there’s no need to be wearing a mask while you apply it. As it’s water-based, you don’t need to worry about weird chemicals in your home. Finally, it’s not got a strong odour, so you won’t need to leave your windows open for hours to get rid of the smell.

Long-lasting

Because it’s designed not to shrink, acoustic sealant will go on doing its job for a lot longer than a non-acoustic caulk without the need to replace it.

Easy to Clean

As with most caulking, you can clean acoustic sealant easily with soap, water and a little elbow grease. No specialist products are required. This also means you can keep it looking good, so you won’t need to replace it often.

You Can Paint It

As you should apply the sealant around light switches, windows, sockets, and to seal the gaps between bits of plasterboard, it’s good to know that acoustic sealant handles paint well. When you’re painting a room, this will ensure you can paint everywhere and still get a nice even finish. Of course, some brands are better than others for this, so do read reviews before you buy.

Cheap

As soundproof product go, acoustic sealant is pretty low cost. It’s worth it for the soundproofing qualities, not to mention the added benefit of better insulation.

Disadvantages of Acoustic Sealant

Not a Complete Soundproofing Solution

Let’s be clear, acoustic sealant will not soundproof your room, or your home, on its own. It’s meant to be a complementary product that you use to seal any remaining gaps left. You may choose green glue compound, which is itself an acoustic sealant, but it is designed to be used on a much larger scale between two pieces of plasterboard.

You could also consider mass-loaded vinyl, acoustic plasterboard, acoustic blankets, and double-glazed windows. Once the main soundproofing is done, check for gaps and fill these in with the sealant.

Takes a Long Time to Dry/Cure

Drying times vary between different brands of sealant, but some can take as much as 48 hours to dry completely. Bear this in mind as it could create a significant delay in moving on to the decorating phase.

More Expensive Than Regular Sealant/Caulk

There’s no getting away from the fact that the upfront cost is higher, which may be an issue if you’re performing a complete renovation. However, remember that you don’t want to spend all that money only for small gaps to negate the benefits. Also, as it’s longer lasting, you shouldn’t need to replace it for a long time… much longer than with standard caulk.

You May Need a New Caulking Gun

Although acoustic sealant comes in tubes (like standard sealant) some brands make their tubes a fair bit larger than normal. If you already own a caulking gun, it’s possible it won’t fit, and you’ll need a bigger one. However, if you do your research into sizes ahead of time, as well as looking at costs per ml, you can decide to look for a smaller tube if it works out better.

Wolfcraft 4355000 Mechanical Caulking Gun
  • For processing almost all materials in 310 ml cartridges, such as...
  • Robust construction of fiberglass reinforced plastic

Last update on 2021-09-20 at 14:53 / Images from Amazon Product Advertising API

Some Brands Attract Dirt

Reviews of some brands say that they seem to attract dirt and look grubby much more quickly than the previous caulking did. If it’s not a high traffic area of your house, this might not be an issue for you, but if you’re worried about the appearance of dirt, then make sure you check out which brands look best over time.

Some Brands Cannot Be Painted

Although being able to paint acoustic sealant was listed as an advantage, be aware that some brands can’t be painted at all, and others don’t accept paint well. If you’re planning to use wallpaper or use the sealant in an area that you don’t plan to paint, this is fine. If painting is important, though, make sure you choose a brand that looks good when painted.

Rockwool Acoustic Intumescent Sealant 310ml
  • Acoustic Intumescent Sealant 310ml

Last update on 2021-09-20 at 14:53 / Images from Amazon Product Advertising API

Conclusion

If you’re completing a soundproofing project, it’s always a good idea to use acoustic sealant. There are gaps in every room, no matter how new, and if you don’t seal them, your soundproofing will not be as effective.

If you’re not doing a complete soundproof and are just replacing your caulking, it’s not as cut and dry. No, it won’t soundproof your room, but it should still reduce the sound a bit, so if that’s not your primary goal, this may be enough. Acoustic sealant also lasts a lot longer, so although it may be more expensive up front, it should save you money long-term.

You May Also Like

About the Author: AJ

AJ writes about living a quieter life, soundproofing tips and recommending the best quiet products here on Quiet Living.

Leave a Reply

Your email address will not be published. Required fields are marked *