How Does Green Glue Soundproofing Work?
When it comes to soundproofing a room, the key is to minimize vibrations. This is particularly important in timber-based construction projects—the norm for America—where lightweight dry walls often struggle to provide adequate noise insulation on their own merit, at least compared to projects that use heavier materials like concrete or masonry.
Green Glue soundproofing technology was developed to address this common problem. By layering the viscoelastic damping compound between two sheets of drywall, builders discovered they could decrease vibrations, which reduced sound transmission from one room to another. This results in more privacy, reduced flanking sound, and a superior acoustic environment overall.
But does Green Glue soundproofing work? If so, how and why?
Read on to learn more about Green Glue and how to use it.
What Is Green Glue?
Despite its name, Green Glue isn’t an adhesive. It doesn’t possess the sticky properties of typical glues, nor does it ever fully harden and set. As a result, it’s effectively useless as a binding agent. However, where Green Glue truly shines is in its role as a damping agent, especially when combined with other fixing materials.
Green Glue is a liquid, waterborne, viscoelastic damping compound. Its unique formulation is specifically intended to enhance a structure’s damping properties, thus enabling it to more effectively dissipate energy over time or distance. By sandwiching the flexible acoustic glue between two rigid layers of drywall or using an acoustic sealant on gaps and seams, Green Glue creates an acoustic-dampening effect that creates better sound insulation.
Green glue is particularly effective in reducing flanking noise paths, which are indirect routes that sound waves travel, typically via adjoining walls, ceilings, and floors. Its viscoelastic properties enable it to absorb and then dissipate vibrational energy, thus reducing structural borne noise transmission from these indirect paths.1
How Does Green Glue Work?
What’s the science behind Green Glue? A viscoelastic substance has a fluid’s viscosity and the elasticity of a gel or a solid. In other words, it has the thickness and flow characteristics of a fluid and the ability to deform and recover its shape like a gel or a solid. That said, a viscoelastic material’s unique characteristics are influenced by various factors, including:2
- Dynamic strain rate
- Static preload
- Time effects like aging, creep, and relaxation
With green glue, these characteristics make it especially useful at blocking and absorbing sound, thus reducing the transfer of noise between rooms or various parts of a building.
Here it’s important to remember that, at its essence, sound is simply frequency vibrations that travel through the air or solid materials. When sound waves encounter a hard surface, they can either pass through it, be reflected, or be absorbed.
In the context of soundproofing a room, the ultimate goal is to reduce the transmission of sound waves from one surface to the other, ideally, by reflecting it back toward the source. And Green Glues’ special properties enable this:3
- Viscosity – Green Glue has high viscosity properties that, when applied between two rigid surfaces, create a viscoelastic layer, which converts sound energy into heat energy through internal friction.
- Damping – The viscoelastic properties of Green Glue allow it to effectively dampen vibrations. When sound waves hit the insular layer of Green Glue, it resists that motion and dampens the amplitude and intensity of the sound waves.
- Decoupling – When applied between two surfaces, Green Glue creates a flexible and resilient barrier that disrupts direct sound vibration transmission from one surface to another. This decoupling method breaks the mechanical connection between two objects, thus minimizing airborne and impact noise.
Benefits of Green Glue for Soundproofing
In the context of soundproofing, Green Glue is the best product available to the construction market. Benefits of using this damping or noiseproofing compound include:
- Effective damping and noise reduction – Green Glue highly versatile solution capable of addressing different noise types and frequencies, enabling it to minimize both airborne and impact noise.
- Cost-efficient – Green Glue provides a better cost-to-performance ratio compared to other damping products, with approximately 16 sq ft per tube at full coverage. Damping requires less material per application, which reduces the materials portion of a soundproofing project’s budget.
- Versatile – Green Glue is remarkably tolerant to real-world application conditions, making it the reliable choice for any project or environment. The noiseproofing compound works to reduce both mid- and low-frequency noises.
- Sustainable – Green Glue is non-toxic and made with eco-friendly materials that are safe for the consumer and the environment. And the green glue tubes are made from 100% recycled materials, which can contribute towards LEED credits as environmentally preferred products.
- Easy application – Soundproofing with Green Glue products is fast and simple. There’s no measuring, troweling, or mixing required. And the caulk gun application takes precision out of the equation. This reduces worker fatigue and accelerates the soundproofing process.
How to Use Green Glue for Soundproofing
Have a soundproofing project in the works? Here’s how to use Green Glue products:
Step 1: Select Your Materials
Before you begin, you’ll need to have the right materials for the job. Green Glue has two primary product offerings:
- Green Glue Compound – Designed for use between layers of building materials.
- Green Glue Sealant – Designed for sealing gaps and seams towards the end of a project.
Let’s say, for this example, you’re damping drywall. In that case, you’ll need both products. In addition to that, you’ll also require a drill, screws, utility knife, and, of course, drywall.
Step 2: Attach Initial Drywall
Using your drill, attach the inner layer of drywall to the studs. Be sure to use the proper screws according to local building codes.
Step 3: Apply Green Glue
Using a standard quart-sized caulk gun, apply the Green Glue randomly to the back of a new sheet of drywall, with a 1- to 2-inch border around the edge of the sheet. For optimal performance, experts recommend that you apply two tubes of green glue noisproofing compound per 4×8 drywall sheet.
Step 4: Attach the Next Drywall Layer
After the Green Glue Compound is applied, lift the drywall into an even position with the initial layer and press firmly to ensure proper contact between the two layers. From there, use screws or fasteners to secure the new layer of drywall in place
Step 5: Seal the Seam Between the Sheets
Seal the seams between the drywall sheets, using a sealant or drywall mud. Make sure to keep it even.
Step 5: Seal the Sheets
Apply the Green Glue sealant to the perimeter of the sheets and around the outlets. Seal cracks, seams, or any other area where sound could escape from.
Step 6: Let the Product Cure
Soundproofing benefits won’t happen immediately since the soundproofing product must cure first. Be patient and don’t disturb the drywall. The curing process could take up to 30 days, depending on climate and conditions.
Does Green Glue Work?
Green Glue provides a damping effect, and it’s one essential part of the soundproofing system—one extra insular layer that helps keep sound out. And the additional mass provided by the new layer of drywall further protects a room against airborne noises.
That said, various factors can impact the effectiveness of green glue, including:
- Building material – As mentioned, this type of solution is useful for lightweight, wooden construction. But, it would have practically no effect if it were slathered onto brick or stone walls. These denser materials are already more sound-resistant than plasterboard, so adding Green Glue would have a minimal impact on their soundproofing capabilities.
- Application – Be sure to follow the recommended application methods and instructions. The compound must be evenly distributed, properly applied, and allowed to set and cure.
- Room design – The design and layout of the space will impact how effective Green Glue is. The presence of doors, windows, and adjoining walls can all impact sound transmission.
How Long Does Green Glue Last?
If you have extra Green Glue, remember its shelf life will expire eventually. It should be effective for at least a year, though if you keep it cool and out of the sun, the product could last much longer.
Before you apply it, check to see if the glue’s consistency is clumpy. If so, the product has gone bad.
Soundproof Your Space with Acoustical Surfaces
Soundproofing a room is a comprehensive process that typically involves several layers. Green Glue is just one piece of the noise-canceling puzzle.
Looking for soundproofing solutions for your business?
At Acoustical Surfaces, we’re leading experts in soundproofing, acoustics, noise control, and vibration control. We offer sound-damping products and the professional expertise you need to design a room built to accommodate your exact acoustic specifications.
- Acoustical Surfaces. The Impact of Green Glue. The Impact of Green Glue on Structure-Borne Sound https://www.acousticalsurfaces.com/wp-content/uploads/The_Impact_of_Green_Glue.pdf
- Nature. Viscoelastic Properties and efficient acoustic damping in confined polymer nano-layers at GHz frequencies. https://www.nature.com/articles/srep33471
- Roush. Viscoelastic Damping 101. https://www.roush.com/wp-content/uploads/2015/09/Insight.pdf
- Acoustical Surfaces. Soundproofing vs Sound Absorbing. https://www.acousticalsurfaces.com/
- University of Northern Colorado. Using Smartphone Apps to Measure Impact Noise. https://digscholarship.unco.edu/
- University of Calgary. Sound. https://energyeducation.ca/
- United States Department of Energy. Double-Stud Wall Framing. https://basc.pnnl.gov/