- What is Green Glue & how does it work?
- How does constrained layer damping work?
- How is Green Glue applied?
- Can I use Green Glue with only one layer of drywall?
- Do I use nails or screws in conjunction with Green Glue?
- Should I use conventional adhesive along with Green Glue?
- How thick is the Green Glue layer?
- Can Green Glue be used in floors?
- Can I treat just the ceiling, or should all surfaces be dealt with?
- Can Green Glue make a high performance wall without decoupling?
- Can Green Glue be used in conjunction with decoupling techniques?
- Will Green Glue perform even better in between drywall and soundboard?
- How does Green Glue compare to other techniques?
- Is Green Glue toxic?
- Is Green Glue a fire hazard?
- How much does Green Glue cost?
- How much do I need?
Sound travels as a wave through the air. It’s an airborne vibration. The waves hit a wall or ceiling and the energy becomes structure-borne. Unless the wall or ceiling material is damped, the vibration will travel through the building framing and exit somewhere else as sound again.
In a constrained layer damping system, sometimes referred to as CLD, a damping material is sandwiched between two other (usually stiff/rigid) materials. For example, Green Glue sandwiched between two layers of drywall. Damping occurs when the viscoelastic center of the “sandwich” is sheared (see right).
When bent, shear forces pull and stretch on the damping material. Under these conditions, the unique polymeric construction of Green Glue very efficiently converts this mechanical energy to heat. The vibration energy is not isolated, it’s dissipated and gone.
Green Glue comes in 29 oz. tubes. You can use any quart size caulk gun, available at most hardware and building material stores. It is very fast and easy to apply. No special skills whatsoever are required. Application Instructions.
No. Green glue needs to be a constrained layer, meaning that Green Glue is sandwiched between to rigid, dense layers of building material. There is no limit to how many drywall / Green Glue layers you can utilize, and performance will improve as the # of layers goes up. You can save valuable $$$ by using slightly less Green Glue in each damping layer if your walls are to have more than 2 layers of drywall. For floors, you can use any common materials (cement board, OSB, plywood, etc.)
Yes. Audio Alloy recommends the use of screws in accordance with local building codes. Screws assist with the compression of the Green Glue layer into a thin film.
No. The presence of rigid, low-damping materials alongside Green Glue between layers is not desirable.
About 0.5 mm.
Absolutely, in fact when used in floors, Green Glue yields a double benefit – it helps with both impact (footstep) noise and airborne sound, and is very effective at both. Green Glue may be used between layers of subfloor, between subfloor and tile backer board, and between thinset mortar and the surfaces below. You may be able to use 2 layers of thinner subfloor if convenient.
If you have a situation where you want, for example, to stop sound from moving upstairs, the most logical path for the sound is through the floor/ceiling into the room above, this is called the direct path. However, sound can make its way upstairs through the walls (or even floor) as well in the form of mechanical vibration. Sound in your room vibrates the walls, this vibration makes its way up where it creates sound by vibrating the surfaces of the upstairs room. Sound making its way through these indirect paths is called flanking noise.
An analogy that is sometimes used when discussing sound isolation is that of an aquarium. If your aquarium has a hole in any of the 5 sides, then the water can spill into the floor, regardless of how tight the other 4 are. The same applies to sound.
For best results, you should consider treating all the surfaces of your room. You may also have to pay attention to other sound paths, such as noise going in and out of doors, and noise making its way through ductwork. Read more about how sound can travel along non-linear paths.
Yes, without a doubt. In fact, Green Glue has performance advantages in many applications relative to some decoupling schemes.
Yes, and better performance can be had. For walls the preferred decoupling methods are double studs > staggered studs > modern sound clips > resilient channel. For applications where low frequency isolation is important, resilient channel is not recommended.
No. Soundboard is far lighter than drywall and isn’t preferable in any ceiling or wall assembly.
We have same-lab, 3rd party data answering this question directly. See our technology page for the details.
No. Green Glue is water based, non-toxic, non-carcinogenic, and very low in VOC (<5grams per liter / compliant in all 50 states and worldwide). As with all products, paints, glues, and so forth, you should use proper precautions and read the MSDS before using Green Glue. Green Glue has a mild odor, typical of latex products. This odor is not dangerous and will dissipate completely given time.
No. Green Glue has been fire tested, and can be utilized in fire-rated walls without affecting the rating of the wall.
About 80 cents per square foot, making a layer of Green the most economical sound isolation product around, as well as one of the best.
Recommended application is 2 tubes of Green Glue per 4′ x 8′ area – 2 tubes per standard sheet of drywall. If you are not on a budget, utilizing 3 tubes per sheet will improve performance. Each case of Green covers about 192 square feet, or 128 square feet if used at the 3 tubes coverage rate. Do not use more than 3 tubes per 4′ x 8′ sheet as performance will actually decline above 3 tubes per sheet. You are just wasting your money!