Acoustic Sealant, also known as acoustic caulk or acoustical caulk, is a product used to seal cracks and gaps in a wide range of construction setups to prevent sound transmission.
As I have often mentioned, sound travels through air and through mediums (such as walls) in the form of vibrations.
Acoustical caulk saves the day by creating an airtight seal that reduces sound transmission in different wall system types.
What is Acoustical Sealant?
As I have already mentioned above, the acoustical sealant is a specialized soundproofing caulk that reduces transmission in all types of wall systems from gypsum, concrete, metal, wood, etc.
It’s one of the cheap soundproofing materials that are non-toxic, flammable, and freeze-thaw stable.
The primary purpose is to improve and maintain a specific Sound Transmission Class (STC) value of walls, floor, or ceilings.
Most acoustic sealants are paintable, adhere to most building construction materials, and easily cleans up with water and soap.
Where Is Acoustical Sealant Used?
Acoustical sealant is used to fill cracks, gaps, and seams to block air and sound transmission.
It’s used around electrical element outlet to protect in a shared wall to protect sound transmission to the next room.
This product is also used to seal any openings around plumbing holes, ductwork, electrical boxes, doors, windows, metal or PVC pipes, etc.
I have been using it to seal the tiny gaps where two walls meet, where walls meet the ceiling or the floor.
This helps prevent noise transmission through the partition.
An acoustic sealant will help block the impact, airborne, and flanking sound transmission in your home.
Is Acoustic Sealant Toxic?
There’s a rant I’ve been keenly following online with some folks complaining on toxicity associated with acoustic caulk.
I’ve practiced DIY soundproofing; I’ve actually handled soundproofing sealant on several occasions.
Through my encounters, I’ve never experienced any sorta a problem with sealants from different brands.
But in one discussion I’ve been following online, a member complained about how the acoustical sealant installer became ill and quit on the first day.
In addition, these sealants often emit strong fumes that can last for a few hours to days, depending on your ventilation system.
While the odor is non-toxic, some people allergic to scents/fragrances will like to develop allergic reactions, including difficulty breathing or headaches when exposed to the sealant’s fumes. (Source)
A-List of The Best Acoustic Sealant for Noise Reduction
Choosing the best sound deadening caulk for your DIY soundproofing project can be a daunting task, especially if it’s your first time.
That shouldn’t worry you anymore, as I have handpicked only the best of the noise-proofing sealants you can get on the market today.
1. Green Glue Noiseproofing Sealant
The best on the market today is the Green Glue noise-proofing sealant.
This product fills the gaps and joints where two walls meet or where the walls meet the ceiling or the floor.
Great for use around switch boxes and any outlet boxes.
For example, green glue is easy to apply and can be painted once dry (after 48 hours)- I’d recommend using soundproof paint for the best results.
This noise-proofing sealant gives the much-needed finishing touch after installing Green Glue Noiseproofing Compound.
It helps improve STC ratings, which is mandatory in LEED-certified facilities.
Additionally, the product is non-hazardous, permanently flexible, and has no odor.
The best part is that independent tests done by Underwriters Labs show that it’s environmentally friendly and meets fire safety requirements.
The manufacturer recommends 0.3 to 0.6 cm (1/8 to 1/4”) gap left for sealing purposes and sealing gaps more than 5/8” isn’t recommended as it doesn’t cure well in such large gaps.
I recommend using a backer rod for gaps deeper than an inch to fill this gap before adding the sealant.
2. Auralex Acoustics STOPGAP Acoustical Sealant
This is a water-based elastic sealant that helps in sound transmission reduction around electrical boxes, perimeter wall systems to improve the Sound Transmission Class (STC) and MTC values.
Once applied, the sealant surface dries up to form a tough film while the inside of the sealant remains flexible.
In addition, Auralex STOPGAP has no residual run-off, meets ASTM E-84 ratings for fire retardancy, non-staining, and is paintable.
To achieve better results, I would recommend attaching an acoustical sound wallpaper to the walls of your house to help significantly reduce sound transmission.
Did you know that:
- StopGap sealant will achieve an STC of 53 if applied as per ASTM C-919. To achieve this, the sealant must be applied as 2 beads of sealant at the bottom, top, and on perimeter edges.
- The 28 oz package covers approx.—32linear ft when a 3/8 per bead.
3. Liquid Acoustical Sound Sealant
Liquid nails are an elastic, long-lasting latex-based sealant designed to reduce sound transmission in every wall system.
The sealant meets ASTM E84 for smoke generation and flame spread.
Additionally, it’s nonflammable and adheres to almost all construction surfaces to maintain specific Sound Transmission Class values.
Cut the sealant nozzle to create a ¼ “6mm opening and insert a cartridge into a caulking gun.
You should then apply 6mm ¼ “beads under runners at the floor and ceiling.
Ideal for any openings, including electrical boxes, cutouts, perimeter joints, and other areas where air infiltration and sound transmission may occur.
4. Quietzone Acoustic Sealant
Just as its name suggests, the Quietzone Acoustic Sealant by Owens Corning absorbs sound vibrations in the wall cavity.
This product stops noise from traveling through the gaps and cracks.
Its great for:
- Electrical boxes/outlets, doors, air ducts, windows, and boots
- Application ideal on gaps between the subfloor and wall stud plates.
- Great for other miscellaneous ceilings, wall, and floor gaps or penetrations.
Here’s a detailed guide video on how to apply Quietzone sealant.
5. Sheetrock® Brand Acoustical Sealant
This is a water-based, flexible fire caulk that’s a no-brainer to apply with simple hand-gun equipment.
The sealant achieves and exceeds all STC/MTC tests.
Additionally, independent tests done at Riverbank Acoustical Laboratories prove that this sealant is in line with ASTM E90 certification and meets STC/MTC partition ratings.
This product is excellent for:
- It’s a compelling sound flanking material
- Permanently flexible even at -18°C (0°F) temperatures
- It has low VOC
- Ideal for usage in sound and/or smoke assemblies
Is Acoustical Caulk Worth It?
If you genuinely value acoustical caulk and would like to deaden the noise from outside from entering your home, the acoustical caulk is genuinely worth it.
Acoustical caulk is one of the many sound-absorbing materials that give the best soundproofing results when combined.
Any hole or gap in your home, even the smallest one, can ruin your overall soundproofing project.
For the purpose of tight sealing the seams and gaps to prevent sound transmission, I would highly recommend you to use an acoustic sealant (caulk).
In conclusion, not only does it help prevent sound transmission, but it also helps improve thermal insulation.
Hi, my name is Todd R. Bressler and I am the founder of this soundproofing blog. I’m a DIY enthusiast from Cincinnati, the city that just beat New York for the City That Never Sleeps Award in 2020. (Original) I have been in the DIY soundproofing industry for close to 5 years, running a YouTube channel and a Podcast show every Saturday. I started Crafty Soundproofing to help you learn the basics of “self defending yourself against noise”
Have an idea worth sharing? Please contact me and I’ll be happy to respond ASAP.