Understanding Decoupling

What Is Decoupling?

Decoupling means mechanically separating the two sides of a wall to make it difficult for vibrations from sound to pass through the wall or ceiling. Here is a simple example of decoupling two sheets of drywall.

And below is a simple sketch of how wood studs couple the conventional wall, and how products like resilient sound clips (GenieClips) can decouple it and improve performance to levels higher than any other product including damping compounds and mass layers.

Coupled Assembly The stiffness of wood studs couples the two sides of a conventional wall. As a result, sound can easily pass from one side, through the studs, to the other side. Sound can pass through this type of wall without going through the air and the insulation, so insulation has only a limited effect on the single wood stud wall.		Decoupled Assembly By including a resilient isolation clip, the sound that tries to pass to the other side via the structure is thwarted by allowing the sound vibrations to flex within the hat channel and clips rather than passing through the structure. Because sound cannot easily pass through the structure, it has to pass through the air cavity, and insulation becomes far more effective.

Invaluable Decoupling Tips

• Use as much mass as possible on each side of the wall. A double layer on one side over single layer is a huge improvement.
• Use as deep an air space as possible.
• Use insulation. Fluffy fiberglass insulation is as good as anything out there. The soundproofing insulation may provide a good boost in a standard framed wall, but once your decoupled wall reaches the low 60s in STC the soundproofing insulation impact will be much less noticeable.
• Select modern sound clips such as GenieClips over resilient channel (lower resonance point)
• Utilize viscoelastic damping (Green Glue Compound) in conjunction with a decoupled assembly.

Decoupling Walls Through Framing

These should be helpful to anybody wondering what the difference is between a standard, staggered, and double stud wall.

Conventional Wall	Staggered Stud Wall  Shown is 2x4 studs offset on a 2x6 base plate.	Double Stud Walls Two separate rows of studs with drywall only on the outside.

Using Resilient Sound Clips

Resilient sound clips are devices that screw to the studs of your wall. Metal furring hat channel is then inserted into the clips, and drywall is screwed into the hat channel. Clips provide decoupling by suspending the drywall on furring hat channel channel about 1.5" from the studs and improve decoupling performance because of the minimal number of connections with clips. The increase in performance by using resilient sound clips (GenieClip, Green Glue Clip, or RSIC-1) is better than the performance of a staggered stud wall with similar construction and equal to the performance of a double stud wall with a 3" gap. Resilient sound clips also provide an affordable alternative to acheive a high rating in a decoupled ceiling without actually setting up inependently framed joists (i.e. room within a room design).