Most common walls are built with a frame…metal in commercial settings / wood in residential settings…with drywall affixed to both sides of the frame. With or without the batting insulation lined between the studs, the framing becomes the equivalent to a string pulled tight between two coffee cans. As air borne sound waves from room A touch the common wall, the framing pulls the vibrations through the assembly and delivers air born sound to the adjoining room.
Old school contractors think to stuff batting insulation or insert “blow in” insulation into a wall cavity. The reality is that this treatment ignores the primary path the noise is actually traveling. The structure born connection points are the culprit, regardless of what is introduced as a potential sound insulation between the joists. Understanding this, how noise travels through a common surface, is your first step in understanding how to defeat it.
The goal with any common wall is to add a combination of “density” and “disconnection” to the assembly. Density impedes vibration, disconnection forces the collapse of the sound wave. Let’s address density first. Think of a wine glass, a guitar string, the face of a drum or a tuning fork. If any of these objects are allowed to vibrate, they will produce sound waves. But if you place your hand on any of them, the vibrations die and so does the sound. Adding density to a surface impedes vibration and kills resonance. Your wall is the same as these objects…by adding density to the wall, you impede its ability to accept and conduct vibration. This density comes in the form of thin weighted vinyl, called dB-Bloc. The material is shipped to your project site in 30′ rolls measuring 54″ in width. The layering technique, for new build or existing/finished walls is featured online at www.controlnoise.com.
The “disconnetion” part comes next. After stapling up the dB-Bloc to collapse the vibrations against the wall, a furring strip system is run horizontally up the wall, criss crossing over the studs inside the wall assembly, to force a disconnection between your new and final drywall layer, to the existing assembly. By placing a 5/8″ drywall layer to the face of these furring strips, you create a dead air gap within your assembly, forcing the collapse of the sound wave. Much like snipping the string pulled tight between two cans.
Now you know how to sound insulate your wall…..stapled up dB-Bloc, add your furring strip system, and then a 5/8″ drywall finish to the face of your strips. The technique is time tested, over 20 years of success, takes just 1.25″ of depth out of the room, and can be applied to new builds or existing/finished surfaces. Tear nothing out, just add to. Need help? Cal for questions to NetWell Noise Control at 1-800-638-9355.